JP5060033B2 - Method for recovering nickel or cobalt - Google Patents

Description

  The present invention relates to a method for recovering nickel or cobalt from oxide ore.

  As a technique for recovering nickel or cobalt from oxide ore, the technique described in Patent Document 1 and the like can be mentioned.

JP-A-60-75536

When recovering nickel or cobalt from oxide ore containing nickel or cobalt, when neutralizing sulfuric acid in a liquid containing nickel or cobalt using calcium in a form such as CaCO ₃ or Ca (OH) ₂ As shown in the following reaction formulas (11) and (13), CaSO ₄ (gypsum) is generated. In addition, a precipitate containing Fe in the form of Fe ₂ (CO ₃ ) ₃ or Fe (OH) ₃ is generated as in reaction formulas (12) and (14), which are formulas showing the reaction of Fe in the liquid. .

H ₂ SO ₄ (free sulfuric acid) + CaCO ₃ (solid) = CaSO ₄ (solid) + H ₂ O + CO ₂ (11)

Fe ₂ (SO ₄ ) ₃ (liquid) + 3CaCO ₃ (solid) = Fe ₂ (CO ₃ ) ₃ (solid) + 3CaSO ₄ (solid) (12)

H ₂ SO ₄ (free sulfuric acid) + Ca (OH) ₂ (solid) = CaSO ₄ (solid) + 2H ₂ O (13)

Fe ₂ (SO ₄ ) ₃ (Liquid) + 3Ca (OH) ₂ (Solid) = 2Fe (OH) ₃ (Solid) + 3CaSO ₄ (Solid) (14)

Precipitates containing Fe, such as Fe ₂ (CO ₃ ) ₃ or Fe (OH) ₃ , were in the form of fine particles because of a fast precipitation reaction. Moreover, since many precipitates containing Fe are produced at the same time as many CaSO ₄ solids are produced, a large amount of neutralization residue is produced. Therefore, there is a problem in the solid-liquid separability between the solid and the liquid after neutralization, the slurry concentration of the neutralization residue that is a solid is low, and a large amount of neutralization residue is generated. Therefore, in order to solid-liquid separate the neutralization residue and the liquid after neutralization, a large-scale solid-liquid separation facility is required, and a large-scale facility for depositing the neutralization residue after the solid-liquid separation may be required. . For this reason, it has been a factor that causes an increase in cost.

  According to the present invention, there is provided a method for recovering nickel or cobalt from a first oxide ore containing nickel or cobalt and iron, wherein the nickel or cobalt is recovered from the first oxide ore using sulfuric acid. Leaching, a leaching step to obtain a sulfuric acid leaching solution containing nickel or cobalt, and a leaching residue, and reacting the sulfuric acid leaching solution containing the leaching residue with magnesium to adjust the pH, and a reaction solution containing nickel or cobalt And a reaction step of obtaining a reaction residue containing iron, neutralizing the liquid obtained in the previous step using a neutralizing agent, and neutralizing solution containing nickel or cobalt, and neutralization containing iron And a neutralization step for obtaining a residue, and including a preliminary neutralization step for increasing the pH of the liquid obtained in the previous step using magnesium between the leaching step and the neutralization step. Features Recovery method is provided.

According to the present invention, magnesium is added before the neutralization step by further including a pre-neutralization step of increasing the pH of the liquid obtained in the previous step using magnesium between the leaching step and the neutralization step. By using it, it is speculated that a residue having good crystallinity and a large particle diameter can be produced. Further, since the MgSO ₄ is liquid is produced by the neutralization reaction of magnesium and free sulfuric acid, it is possible to suppress the formation of solids. Therefore, the separability between the solid material and the liquid generated in the neutralization step can be improved. Therefore, the generation amount of the neutralization residue can be reduced.

  In the present invention, the pre-neutralization step is performed between the reaction step and the neutralization step, and the pre-neutralization step uses the reaction liquid containing the reaction residue and the second oxide ore containing magnesium and nickel. It may be a step of neutralizing and obtaining a liquid containing nickel or cobalt and a residue containing iron. In this way, by using magnesium in the second oxide ore as a neutralizing agent, free sulfuric acid and iron in the reaction solution can be made more efficient without coprecipitation of nickel or cobalt in the reaction solution. Can be removed. Moreover, since the nickel in the second oxide ore can be recovered as nickel sulfate, the nickel recovery rate can be further improved.

  In addition, before the leaching step, a classification step of classifying the first oxide ore into a small particle size oxide ore and a large particle size oxide ore containing magnesium is included. Alternatively, while leaching cobalt, in the reaction step, the sulfuric acid leaching solution containing the leaching residue and magnesium contained in the large particle size oxide ore are reacted to adjust pH, and the magnesium content of the second oxide ore is: It may be higher than the magnesium content of the large particle size oxidized ore. By carrying out like this, the processing cost for removing iron can be reduced more, obtaining a higher recovery rate of nickel or cobalt with a small amount of sulfuric acid used. Moreover, the nickel content of the second oxide ore may be lower than the nickel content of the large particle size ore.

  Further, in the leaching process, sodium or cobalt is further leached from the first oxide ore to obtain a sulfuric acid leaching solution containing nickel or cobalt and a leaching residue, and in the reaction process, leaching is performed. The pH of the sulfuric acid leaching solution containing the residue may be adjusted to obtain a reaction solution containing nickel or cobalt and a reaction residue. In this way, in the leaching process, natrojarosite is generated using sulfuric acid and sodium salt, and in the reaction process, the pH is adjusted using magnesium in the reaction process to precipitate natrojarosite. The iron concentration of can be further reduced. For this reason, in a neutralization process, in order to reduce the iron concentration in a reaction liquid, it is not necessary to use a lot of neutralizing agents. Therefore, in the nickel or cobalt recovery process, nickel or cobalt can be recovered more efficiently by obtaining a high leaching rate of nickel or cobalt while further reducing the processing cost for removing iron. it can.

  The sodium salt may be a sodium salt contained in seawater. By carrying out like this, the processing cost for removing iron can be reduced, obtaining the high recovery rate of nickel or cobalt. The amount of sodium salt used may be 1% by weight to 5% by weight of the amount of the first oxide ore used. By carrying out like this, the increase in the cost which collect | recovers nickel or cobalt from an oxide ore can be suppressed more, obtaining the high recovery rate of nickel or cobalt by obtaining the high leaching rate of nickel or cobalt. Further, the sodium salt may be a sodium salt contained in the concentrated seawater, and the concentration thereof may be 4 wt% or more and 5.3 wt% or less.

  In the leaching step, nickel or cobalt may be further leached from the first oxide ore using a reducing agent to obtain a sulfuric acid leaching solution containing nickel or cobalt and a leaching residue. By carrying out like this, the recovery rate of cobalt can be improved more. Further, the reducing agent may be iron powder. By doing so, it is possible to stably improve the leaching rate of cobalt while suppressing an increase in recovery cost.

  Moreover, you may perform both a leaching process and a reaction process under the temperature of 90 degreeC or more. By doing so, the leaching rate of nickel or cobalt can be further improved. Further, both the leaching step and the reaction step can be performed under normal pressure. By doing so, an increase in equipment cost can be suppressed.

  Moreover, after the neutralization step, the neutralization solution and the neutralization residue are subjected to solid-liquid separation using a flocculant and a thickener to separate the neutralization solution and the neutralization residue, Further, it may be included.

  Moreover, you may perform a preliminary | backup neutralization process under the temperature of 90 degreeC or more. By doing so, the pH can be increased more efficiently.

  Further, the neutralizing agent may be slag containing magnesium. By carrying out like this, the processing cost for removing iron can be reduced more, obtaining the high recovery rate of nickel or cobalt.

  In the leaching step, the amount of sulfuric acid used may be 50% by weight or more and 80% by weight or less of the amount of the first oxide ore used. By carrying out like this, the raise of the recovery cost of nickel or cobalt can be suppressed, obtaining the high leaching rate of nickel or cobalt.

  According to the present invention, by including a preliminary neutralization step of adjusting pH using magnesium between the leaching step and the neutralization step, it is possible to improve the separability during solid-liquid separation.

  1 and 2 are process flow diagrams.

  Embodiments of the present invention will be described below with reference to the drawings and tables. In the following description, the amount used and the amount added are the amount used and the amount added based on the weight of each substance.

  In general, there is no clear component range for limonite ore and saprolite ore, but the oxide ore with high iron and low magnesium is expressed as limonite ore, and the iron ore with low iron and high magnesium is expressed as saprolite ore. There are many. Table 1 shows the components of oxide ore called limonite ore, oxide ore called saprolite ore, and ferronickel slag.

  Hereinafter, terms in the present embodiment will be described.

  In the present embodiment, the low Ni high Mg oxide ore means that the nickel content is 2% by weight or less, the Fe content is 20% by weight or less, the magnesium content is 15% by weight or more, FeNi by dry smelting (Ferronickel) It has been rarely used in the production of so far and refers to so-called low Ni grade saprolite ore.

  On the other hand, the oxide ore usually used in dry smelting is generally called saprolite ore, and its components are Ni: 2 wt% or more, Fe: 20 wt% or less, Mg: 15 wt% That's all.

  Dry smelting is a method for producing FeNi (ferronickel), which is a raw material for stainless steel and nickel alloy steel, by melting and reducing nickel and Fe together with a reducing agent such as coal by electric energy. Here, if the nickel grade in the oxide ore is low and the Fe grade is high, the nickel grade of FeNi (ferronickel) produced by dry smelting is lowered. Therefore, when producing stainless steel or nickel alloy steel, the energy intensity increases, and there is a problem in terms of economy. Therefore, it is considered difficult to use low Ni grade saprolite ore as a dry smelting raw material.

  Hereinafter, the component ranges of limonite ore and saprolite ore will be described.

  The component distribution in the nickel oxide ore deposit will be described with reference to FIG.

  The nickel component tends to increase as it becomes deeper from the ground surface, but rapidly decreases in the vicinity of the bedlock. The nickel component of the oversize (large particle size) ore is higher in the upper layer of the limonite ore layer than the nickel component content of the undersize (small particle size) ore, and the lower layer of the limonite ore layer and the saprolite ore layer It tends to be lower. In FIG. 4, the ore deposit in which the nickel component of the saprolite ore layer is 2 wt% or more has been described, but depending on the ore deposit, the nickel component is 2 wt% or less, for example, 1 wt% or more and 1.4 wt%. It may be the following.

  The cobalt component tends to increase as it becomes deeper from the ground surface, but rapidly decreases from the vicinity of the saprolite ore layer. The cobalt component of the large particle size ore has almost the same tendency as the nickel component.

  The Fe component tends to decrease as it becomes deeper from the ground surface, but rapidly decreases as it approaches the saprolite ore layer. The Fe component of the large particle size ore is lower than the Fe component of the small particle size ore, and this tendency is remarkable in the limonite ore layer.

  The magnesium component tends to increase as it becomes deeper from the ground surface, but increases rapidly as it approaches the saprolite ore layer. The magnesium component of the large particle size ore is higher than the magnesium component of the small particle size ore, and this tendency is remarkable in the limonite ore layer.

  Here, the saprolite ore layer is an ore layer mainly used for producing ferronickel by dry smelting using an electric furnace, and the limonite ore layer is an ore layer mainly used for wet smelting.

(Embodiment)
FIG. 1 and FIG. 2 show process diagrams for recovering nickel and cobalt from oxide ore containing nickel, cobalt and iron.

  Hereinafter, the process flow in the present embodiment will be described.

  First, in step a (classification step (S1)), the oxidized ore 102 is classified into an oversize and an undersize, the undersize is made into slurry ore 104 with water 107, and the oversize is crushed into a pulverized product 103.

  Next, in step b (leaching step (S2)), sulfuric acid 105 is added to the slurry ore 104 to leach with sulfuric acid 105, thereby obtaining a sulfuric acid leach solution 108 containing nickel and cobalt and a leach residue 109. Here, the leaching residue 109 includes natrojarosite produced by the reaction of iron leached from the slurry ore 104, sulfuric acid 105, and sodium salt 106.

  Subsequently, in step c (reaction step (S3)), free sulfuric acid in the sulfuric acid leachate 108 containing the leaching residue 109 is reacted with magnesium contained in the pulverized product 103 pulverized in the classification step. And the pH is adjusted to obtain a reaction solution 110 and a reaction residue 111. By adjusting the pH, natrojarosite is precipitated in the reaction residue 111, whereby the iron concentration in the reaction solution 110 can be reduced.

  Next, in step d (first neutralization step (S4)), the reaction is performed with magnesium contained in the oxide ore 300 by adding the low Ni high Mg oxide ore 300 to the reaction liquid 110 including the reaction residue 111. By the reaction with the free sulfuric acid in the liquid 110, a first neutralized liquid 302 in which the free sulfuric acid is further consumed and a first neutralized residue 304 in which iron is precipitated as natrojarosite are obtained. Therefore, the free sulfuric acid and the iron concentration in the first neutralization liquid 302 can be further reduced from the reaction liquid 110.

  Next, in step e (second neutralization step (S5)), the neutralization agent 112 is added to the first neutralization solution 302 containing the first neutralization residue 304 to adjust the pH. A liquid 113 and a second neutralization residue 114 are obtained. Here, in the first neutralization step of the previous step, the iron concentration in the first neutralization liquid 302 is reduced by precipitating natrojarosite, and the amount of free sulfuric acid is also reduced. Can be reduced.

  Next, in step f (solid-liquid separation step (S6)), the flocculant 115 is added to the second neutralization solution 113 containing the second neutralization residue 114, and solid-liquid separation is performed using a thickener. The two neutralization liquids 113 and the second neutralization residue 114 are separated. Here, the solid-liquid separation property of the second neutralization residue 114 is excellent. This is presumably because the second neutralization residue 114 has good crystallinity and large particles.

  Next, in step g (solvent extraction step (S7)), using the organic solvent 134 as the extraction solvent, the nickel and cobalt contained in the second neutralization solution 113 are replaced with the nickel sulfate solution 130 and the cobalt sulfate solution 132. And sent to the solidification step (step h). Here, by using an organic solvent having a monothiophosphinic acid group as the organic solvent 134, a cobalt sulfate solution 132 containing almost no magnesium, manganese or calcium can be obtained.

  Next, in the step h (solidification step (S8)), the nickel hydroxide 138 and the cobalt hydroxide 140 are obtained by mixing the alkali compound 136 with the nickel sulfate solution 130 and the cobalt sulfate solution 132, respectively. As the alkali compound, magnesium oxide, magnesium hydroxide, sodium hydroxide, sodium carbonate, or the like can be used.

  Next, in the step i (sulfur / chlorine removal step (S9)), the water 205, the metal hydroxide 202 containing nickel or cobalt in a slurry state, and the sodium hydroxide 203 are mixed and stirred, and filtered. -By washing with water, a metal hydroxide 206 containing nickel or cobalt from which sulfur or chlorine has been removed and a solution 208 are obtained.

  Next, in step j (ferronickel production step (S10)), metal hydroxide 206, oxide ore 218, and coal 210 are mixed and reduced (calcined) with a rotary kiln or the like. Next, the reduced mixture is charged into an electric furnace and melted to obtain ferronickel 212.

  Details of each step will be described below.

Step a: Classification step For example, two types of oxide ores 102 containing nickel, cobalt, magnesium and iron, for example, No1 and No2 obtained from mines with different production areas, are oversized with a simple device such as vibration shaker. The undersize is made into a slurry ore 104 using water 107, and the oversize is made into a pulverized product 103 by using a device such as a ball mill. The size of classification using a vibration sieve or the like is not particularly limited, but from the viewpoint of improving process stability, for example, a screen having a size of 0.5 mm or more and 2 mm or less can be used.

  Moreover, when this oxide ore is classified with a sieve of 0.5 mm or more and 2 mm or less, the iron content tends to be high in the undersize and the magnesium content tends to be low. On the contrary, the iron content is low in the oversize. The magnesium content tends to be high.

  As the irrigation water 107, seawater can be used as well as river water and groundwater, which are usually used. Moreover, the high concentration seawater obtained with the apparatus which desalinates seawater can also be used. The concentration of sodium chloride in sea water is about 3.5% by weight, and the concentration of sodium chloride in the concentrated high-concentration sea water is, for example, 4% by weight to 5.3% by weight, It can be 5 wt% or more and 5.3 wt% or less. Here, in adopting the method according to the present embodiment, in consideration of economics such as cost, it may be performed at the mine source. This is because it may not always be easy to secure sufficient water such as river water and groundwater in consideration of the regional characteristics of the mine area. In addition, by using seawater as the irrigation water 107, in the leaching step and the reaction step, which are the subsequent steps, using the sodium salt contained in the seawater, the iron leached from the oxide ore in the leachate and in the reaction solution The effect that the remaining amount can be controlled can be obtained. Moreover, when a desalination apparatus is used, the effect that the obtained fresh water can be used for domestic water, such as drinking water, industrial water used for the manufacturing process of nickel and cobalt, etc. can be acquired.

Step b: Leaching step The slurry ore 104 obtained in step a is leached by adding sulfuric acid 105 at a temperature not lower than 90 ° C. and not higher than 100 ° C. under normal pressure, for example, nickel, cobalt, magnesium. And the sulfuric acid leaching solution 108 containing iron and the leaching residue 109 are obtained.

  By setting the leaching temperature to 90 ° C. or higher, the leaching rate of nickel and cobalt in the slurry ore 104 can be improved. Thereby, the leaching time of nickel and cobalt contained in the slurry ore 104 can be shortened. In addition, the leaching rate of nickel and cobalt can be increased. Further, by leaching nickel and cobalt contained in the slurry ore 104 at a temperature of 100 ° C. or lower, the leaching of nickel and cobalt can be performed at a temperature lower than the boiling point of water. Therefore, it is not necessary to pressurize the leaching container of the apparatus used for leaching nickel and cobalt. Therefore, an increase in equipment cost can be suppressed.

  Although the leaching temperature is 90 ° C. or higher, the temperature may be appropriately selected within a range of 70 ° C. or higher, for example. Further, the nickel and cobalt in the slurry ore 104 may be leached under exceeding 100 ° C. In addition, nickel and cobalt in the slurry ore 104 may be leached under pressure conditions other than normal pressure.

  The amount of sulfuric acid added can be 0.5 times or more and 0.8 times or less (50% or more and 80% or less) by weight of the oxide ore 102 used. By adding 0.5 times the weight (50% by weight) or more of sulfuric acid, leaching of nickel and cobalt can be sufficiently performed. Further, when the addition amount of sulfuric acid is around 0.8 times weight (80% by weight), the leaching rates of nickel and cobalt are in an equilibrium state. For this reason, the generation amount of an excess sulfuric acid (free sulfuric acid) can be suppressed by making the addition amount of a sulfuric acid into 0.8 times weight (80 weight%) or less. Therefore, an increase in nickel and cobalt recovery costs can be suppressed while maintaining the leaching rate of nickel and cobalt from the oxide ore.

  Moreover, in the process b, the reason for using the undersized ore classified in the classification process is as follows. That is, in the undersized ore, nickel and cobalt in the oxidized ore are less likely to be leached than the pulverized product 103 of the oversized ore. Moreover, since the oversized ore pulverized product 103 has a higher magnesium content than the undersized ore, the free sulfuric acid used for leaching may be consumed. Therefore, the recovery rate of nickel and cobalt is improved by first leaching more nickel and cobalt in the oxide ore by using excess sulfuric acid.

  When river water or groundwater is used as the water 107 in step a, a sodium salt 106 such as sodium sulfate or sodium chloride is added in step b. As a result, the amount of sodium added by the sodium salt 106 should be about 0.01 to 0.05 times the weight (1 to 5% by weight) relative to the amount of oxide ore 102 used. it can. On the other hand, when seawater is used as the irrigation water 107, sodium is not contained in the seawater because it contains about 10 g / l of sodium. Therefore, it is possible to further suppress an increase in nickel and cobalt recovery costs while maintaining the leaching rate of nickel and cobalt from the oxide ore.

  Here, when the amount of sodium added is 0.01 times weight (1% by weight) or more, the iron leached from the oxide ore reacts with the sodium sulfate in the sulfuric acid leachate 108, whereby the sulfuric acid leachate 108 contains The iron concentration can be reduced.

  The reason why the concentration of iron in the sulfuric acid leachate is controlled by sodium is considered to be due to the following chemical reaction formulas (1) to (3).

FeO (OH) · (oxide ore) + 3 / 2H ₂ SO ₄ = 1 / 2Fe ₂ (SO ₄ ) ₃ · (liquid) + 2H ₂ O (1)

Fe ₂ (SO ₄ ) ₃ · (Liquid) + 1 / 3Na ₂ SO ₄ + 4H ₂ O = 2 / 3NaFe ₃ (SO ₄ ) ₂ (OH) ₆ · (solid) + 2H ₂ SO ₄ (2)

Fe ₂ (SO ₄ ) ₃ · (Liquid) + 2 / 3NaCl + 4H ₂ O = 2 / 3NaFe ₃ (SO ₄ ) ₂ (OH) ₆ · (Solid) + 2 / 3HCl + 5 / 3H ₂ SO ₄ (3)

  That is, iron in the oxide ore is leached with excess sulfuric acid, but natrojarosite is generated by combining with sodium in the sulfuric acid leaching solution, and a part of the leached iron is precipitated. Therefore, when the iron leached from the oxide ore is contained in the leachate, the amount brought into the reaction process, which is the next process, is reduced. Therefore, in the reaction step, the precipitate can be sufficiently removed as natrojarosite. Therefore, in the neutralization process which is the next process of the reaction process, it is possible to suppress an increase in cost for precipitating iron in the neutralized solution. As a result, an increase in cost for recovering nickel and cobalt from the oxide ore can be suppressed.

  Further, when the sodium addition amount is around 0.05 times the weight (5% by weight), the formation rate and the precipitation rate of natrojarosite are in an equilibrium state. For this reason, by making the addition amount of sodium 0.05 times weight or less, addition of excess sodium can be suppressed, and an increase in cost for recovering nickel and cobalt from oxide ore can be suppressed. .

  The leaching time can be, for example, 1 hour or more and 10 hours or less, preferably 3 hours or more and 6 hours or less. Here, the equipment necessary for the leaching process is, for example, a container with a stirrer that is generally used, and the material thereof is, for example, stainless steel or a steel-lined material. . Therefore, nickel and cobalt can be leached from the oxidized ore 102 without using expensive equipment such as a titanium-lined autoclave, which is used in pressure leaching at high temperature and pressure. Therefore, an increase in cost required for recovery of nickel and cobalt can be suppressed.

Step c: Reaction step The sulfuric acid leachate 108 and leach residue 109 obtained in step b and the oversized ore pulverized product 103 obtained in step a are, for example, 90 ° C. or higher and 100 ° C. under atmospheric pressure. The reaction is carried out at the following temperature based on the formulas (4) to (7) described later. Based on the reaction formula described later, a reaction liquid 110 containing nickel, cobalt, magnesium and a small amount of iron and a reaction residue 111 are obtained.

  The addition method of the pulverized product 103 may be added as a solid as it is, or may be added as a slurry using water. The water used in this step may be any of river water, groundwater, and seawater. Further, a sodium salt 106 such as sodium sulfate or sodium chloride may be added to these waters for use. Moreover, you may use the high concentration seawater obtained by the desalination apparatus. The concentration of sodium chloride in the high-concentration seawater is, for example, 4 wt% or more and 5.3 wt% or less, and can be 5 wt% or more and 5.3 wt% or less.

  Here, when the reaction temperature is 90 ° C. or higher, the leaching rate of nickel and cobalt contained in the pulverized product 103 can be improved. In addition, the efficiency of precipitation removal of the iron leached in step b as natrojarosite can be improved. Moreover, by making it react at the temperature of 100 degrees C or less, reaction based on the chemical formula mentioned later can be made at the temperature below the boiling point of water. For this reason, it is not necessary to pressurize the reaction container of the apparatus used for the said reaction. Therefore, an increase in equipment cost can be suppressed.

  Here, a reaction based on the chemical formula described below may be performed under a reaction temperature of less than 90 ° C. or more than 100 ° C. Moreover, you may make it react based on the chemical formula mentioned later under pressure conditions other than atmospheric pressure.

  In this embodiment, the iron concentration of the sulfuric acid leachate 108 in step b is 30 g / l to 90 g / l, and free sulfuric acid is contained in an amount of 30 g / l or more. As a result of the reaction, the iron concentration is reduced to 1/10 or less and the free sulfuric acid is reduced to 1/3 or less as compared with the sulfuric acid leachate 108 before the reaction.

  This reason is considered to be due to the following chemical reaction formulas (4) to (7).

H ₂ SO ₄ (free sulfuric acid) + MgO (oxide ore) = MgSO ₄ (liquid) + H ₂ O (4)

Fe ₂ (SO ₄ ) ₃ · (Liquid) + 1 / 3Na ₂ SO ₄ + 4H ₂ O = 2 / 3NaFe ₃ (SO ₄ ) ₂ (OH) ₆ · (solid) + 2H ₂ SO ₄ (5)

Fe ₂ (SO ₄ ) ₃ · (Liquid) +2/3 NaCl + 4H ₂ O = 2 / 3NaFe ₃ (SO ₄ ) ₂ (OH) ₆ · (Solid) + 2 / 3HCl + 5 / 3H ₂ SO ₄ (6)

_{Fe 2 (SO 4) 3 ·} ( _{liquid) + 4H 2 O = 2FeO (} OH) · ( _{solid) + 3H 2 SO 4 (7} )

  That is, according to the equation (4), the free sulfuric acid in the sulfuric acid leachate 108 reacts with the magnesium contained in the pulverized product 103, and the amount of free sulfuric acid decreases, thereby increasing the pH in the liquid. For this reason, as the pH in the liquid increases, natrojarosite and goethite are generated and iron precipitates according to formulas (5) to (7).

  When the oxide ore 102 contains iron and magnesium, the above reaction can be caused more efficiently. For example, when the magnesium / iron component ratio is 0.125 or more, the amount of iron contained in the oxidized ore 102 is relatively small. Therefore, the amount of iron leached from the oxidized ore in the leaching step according to the equation (1). Is relatively low. Therefore, the iron concentration in the reaction solution can also be lowered. Further, since the amount of magnesium contained in the oxide ore 102 is relatively large, the amount of magnesium that reacts with free sulfuric acid brought into the reaction process from the sulfuric acid leachate 108 becomes relatively large. For this reason, the free sulfuric acid in the sulfuric acid leachate 108 can be sufficiently consumed using magnesium by the reaction of the formula (4).

  As described above, by containing iron and magnesium in the oxide ore 102, it is possible to sufficiently precipitate iron according to the formulas (5) to (7), and the concentration of iron remaining in the reaction solution 110. Can be reduced. For this reason, the amount of iron remaining in the reaction solution 110 and brought into the neutralization step is reduced. Therefore, an increase in cost required to precipitate iron in the neutralization step can be suppressed. As a result, an increase in cost required for recovering nickel and cobalt can be suppressed.

  Note that there is no upper limit to the magnesium / iron component ratio. The oxide ore 102 used in this embodiment is a limonite ore containing 20 wt% or more and 50 wt% or less of iron and 2.5 wt% or more and 15 wt% or less of magnesium. The ratio will not be greater than 0.75.

  The reason why the oversized pulverized product 103 is used in the step c is that the oversized pulverized product 103 has a higher magnesium content than the undersize, and therefore the reactions of the formulas (4) to (7) are more This is because it proceeds effectively. The reaction time can be, for example, 3 hours or more and 10 hours or less, preferably 4 hours or more and 6 hours or less, and the reaction time is shorter than when using the oxidized ore before classification (4 ) To (7) can be terminated. Here, since the oversized pulverized product 103 contains nickel and cobalt, by leaching the nickel and cobalt in the pulverized product 103 while reacting free sulfuric acid with magnesium and adjusting the pH, The recovery rate of nickel and cobalt can be further improved. Therefore, it is possible to further improve the recovery rate of nickel and cobalt while suppressing an increase in cost required for recovery of nickel and cobalt. In addition, although consumption of the free sulfuric acid using magnesium is performed also in the process d mentioned later, performing in the process c is also meaningful.

  Here, the equipment necessary for the reaction step is, for example, a container with a stirrer that is generally used, and the material thereof is, for example, a stainless steel or a steel-lined rubber lining. is there. Therefore, the reaction in this step can be performed without using expensive equipment such as a titanium-lined autoclave, which is used in the reaction at high temperature and high pressure. Therefore, an increase in cost required for recovery of nickel and cobalt can be suppressed.

  Further, in this step, simultaneously with the oversized pulverized product 103, among the ferronickel slag used in the neutralization step, one having a relatively high nickel content may be used at the same time. In this case, the final pH during the reaction can be used within a range of less than 3. This is because, when the pH is less than 3, the presence of free sulfuric acid in the liquid can suppress a decrease in the leaching efficiency of nickel from the oxide ore.

Step d: First neutralization step (preliminary neutralization step)
Pre-neutralization is performed using oxide ore 300 (Table 1), which is a low Ni grade saprolite ore that is difficult to use in dry smelting as a low Ni high Mg oxide ore. In the present embodiment, when the oxide ore 300 is used, the entire amount is pulverized. The diameter during pulverization is desirably 2 mm or less.

  The addition of the oxidized ore 300 may be added as a solid as it is, or may be added as a slurry using water. The irrigation water may be river water, ground water, or sea water. Further, sodium salts such as sodium sulfate and sodium chloride may be added. Moreover, you may use the high concentration seawater obtained by the desalination apparatus. The concentration of sodium chloride in the high-concentration seawater is, for example, 4 wt% or more and 5.3 wt% or less, and can be 5 wt% or more and 5.3 wt% or less.

  For example, the reaction is carried out at a temperature of 90 ° C. or higher and 100 ° C. or lower under atmospheric pressure (normal pressure) based on formulas (4) and (8) to (10) described later. Based on the reaction formula described below, a first neutralization liquid 302 and a first neutralization residue 304 containing nickel, cobalt, magnesium and a small amount of iron are obtained.

  Here, when the neutralization temperature is 90 ° C. or higher, the reaction rate between magnesium contained in the oxide ore 300 and free sulfuric acid in the reaction solution can be increased. Moreover, the neutralization reaction can be effectively generated. Moreover, the neutralization reaction based on the chemical formula mentioned later can be made at the temperature below the boiling point of water by neutralizing at the temperature of 100 degrees C or less. For this reason, it is not necessary to pressurize the reaction container of the apparatus used for the said neutralization reaction. Therefore, an increase in equipment cost can be suppressed.

  Here, a reaction based on the chemical formula described below may be performed under a leaching temperature of less than 90 ° C or more than 100 ° C. Moreover, you may make it react based on the chemical formula mentioned later under pressure conditions other than atmospheric pressure.

  The neutralization reaction time in the first neutralization step can be, for example, 1 hour or more and 8 hours or less, and preferably 2 hours or more and 4 hours or less. By doing so, the neutralization reaction is in an equilibrium state.

  The pH adjustment may not be performed in the first neutralization step. This is because this process is a reaction between magnesium in the low Ni grade saprolite ore and free sulfuric acid in the liquid, and does not increase to a pH in the range where nickel is co-precipitated.

  The reaction in this step is based on the following reaction formulas (4) and (8) to (10).

H ₂ SO ₄ (free sulfuric acid) + MgO (oxide ore) = MgSO ₄ (liquid) + H ₂ O (4)

2H ₂ SO ₄ (free sulfuric acid) + NiO (oxide ore) + MgO (oxide ore) = NiSO ₄ (liquid) + MgSO ₄ (liquid) + 2H ₂ O (8)

Fe ₂ (SO ₄ ) ₃ (liquid) + 3MgO (oxide ore) + H ₂ O = 2FeO (OH) (solid) + 3MgSO ₄ (solid) (9)

Fe ₃ (SO ₄ ) ₃ (Liquid) +2/3 NaCl + 7 / 3MgO (Oxide Ore) + 2H ₂ O = 2 / 3NaFe ₃ (SO ₄ ) ₂ (OH) ₆ (Solid) +2/3 MgCl (Liquid) + 5 / 3MgSO ₄ ( Liquid) + 1/6 O ₂ (10)

As shown in the reaction formulas (4) and (8), free sulfuric acid still present in the reaction step reacts with MgO and NiO in the oxide ore 300 to consume free sulfuric acid and at the same time nickel in NiO becomes Ni sulfate. As recovered. In this case, MgSO ₄ and NiSO ₄ are both liquids as reactants and do not produce a solid.

In the neutralization reaction of the reaction formula (4), the reaction proceeds gently due to the crystal structure of the composite oxide constituting the oxide ore 300, so that free sulfuric acid is gradually consumed. Examples of the composite oxide constituting the oxide ore 300 include a composite oxide of MgO.SiO ₂ and FeO (OH), a composite oxide of MgO.SiO ₂ and Fe ₂ O ₃ , and the like. Accordingly, Fe in the liquid is precipitated as goethite FeO (OH) or natrojarosite NaFe ₃ (SO ₄ ) ₂ (OH) ₆ according to reaction formulas (9) and (10), and removed as a neutralization residue. In addition, the separability between the second neutralized liquid 113 and the second neutralized residue 114 in the thickener or the like in the solid-liquid separation process (process f), which is a subsequent process, is improved. This is because the neutralized residue in which the reaction has progressed gently has good crystallinity and is assumed to have a large particle size. In addition, although the neutralization reaction of Reaction formula (4) is performed also in the step c, the separation between the second neutralization solution 113 and the second neutralization residue 114 is further improved by performing the neutralization reaction in this step as well.

In addition, under the above mild reaction conditions, the generation of fine particles or gel-like substances such as Fe (OH) ₃ that hinders the improvement of solid-liquid separation properties is suppressed.

  As described above, in this step, by using magnesium in the oxide ore 300 (low Ni grade saprolite ore) as a neutralizing agent, the reaction solution can be obtained without coprecipitation of nickel and cobalt in the reaction solution 110. It is possible to neutralize and remove free sulfuric acid and iron. The pH in the first neutralized liquid 302 thus obtained is, for example, in the range of 1 to 4 and preferably in the range of 1.5 to 2.5. Further, the iron concentration is 5 g / l or less. By setting the pH of the first neutralization liquid 302 in the range of 1 or more and 4 or less, it is possible to more efficiently produce a residue having excellent separability, and the pH is in the range of 1.5 or more and 2.5 or less. By doing so, it is possible to more efficiently produce a residue having excellent separability. Therefore, the neutralization operation load by the 2nd neutralization process (process e) of the following process can be reduced, and the usage-amount of the neutralizing agent 112 can be reduced. Moreover, the coprecipitation rate of nickel and cobalt can be reduced.

  Furthermore, nickel in the oxide ore 300 can be recovered as nickel sulfate in the pH range of the neutralizing solution.

Step e: Second neutralization step By performing a neutralization reaction using the first neutralization liquid 302, the first neutralization residue 304, and the neutralizing agent 112 obtained in step d, for example, the pH is 2 or more. 6 or less, preferably, the pH can be in the range of 2.5 to 5. Thereby, the second neutralization liquid 113 and the second neutralization residue 114 containing nickel, cobalt, and magnesium having an iron concentration of 1 g / l or less are obtained. Here, when the pH is 2 or more, iron can be sufficiently precipitated, and when the pH is 6 or less, most of iron is precipitated and removed while suppressing the coprecipitation of nickel and cobalt. The Therefore, the recovery rate of nickel and cobalt can be improved.

  Here, the pressure in this step is not particularly limited. For example, the neutralization reaction is performed using the first neutralization liquid 302, the first neutralization residue 304, and the neutralizing agent 112 under atmospheric pressure. Alternatively, the neutralization reaction may be performed under a pressure condition other than atmospheric pressure.

  As the neutralizing agent 112, alkaline earths such as sodium hydroxide and potassium carbonate, which are alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide, which are commonly used, are commonly used. Use metal hydroxides such as calcium hydroxide and magnesium hydroxide, alkaline earth metal oxides such as calcium oxide and magnesium oxide, and alkaline earth metal carbonates such as calcium carbonate and magnesium carbonate be able to. Moreover, the ferronickel slag shown in Table 1 can also be used. Moreover, the above-mentioned neutralizing agent may be used by 1 type, and 2 or more types may be mixed and used for it.

  The ferronickel slag refers to a slag containing magnesium generated when ferronickel is produced by a dry smelting method using an ore containing magnesium containing 2 wt% or more of nickel. The amount of ferronickel slag generated in the dry smelting method is about 30 times to 35 times the weight of nickel 1, but only a part is effectively used.

  For example, by using ferronickel slag containing magnesium as the neutralizer 112, the magnesium contained in the ferronickel slag can be effectively used as a neutralizer, and the first neutralization liquid 302 and the first neutralization are used. The residue 304 can be neutralized. Therefore, it is possible to effectively use resources and suppress an increase in nickel and cobalt recovery costs.

  Moreover, as the neutralizing agent 112, if the 1st neutralization liquid 302 and the 1st neutralization residue 304 can be neutralized, other than ferronickel slag, for example, calcium hydroxide, magnesium hydroxide, calcium oxide, oxidation Magnesium, calcium carbonate, magnesium carbonate and the like may be used.

  By neutralizing the reaction liquid 110 using the low Ni grade saprolite ore in the first neutralization process which is the previous process, the concentration of free sulfuric acid and iron in the first neutralization liquid 302 is sufficiently low. Therefore, the amount of iron precipitates in the form of gel or fine particles precipitated by the neutralizing agent 112 can be reduced. Moreover, the amount of gypsum generated when calcium is used as a neutralizing agent can be reduced. Therefore, in the operation of the neutralization step, it is possible to suppress the occurrence of a stirring trouble due to an increase in the viscosity of the neutralized residue slurry, and it is possible to improve the operation efficiency.

Step f: Solid-liquid separation step The second neutralization solution 113 and the second neutralization residue 114 obtained in the step e are separated by adding a flocculant 115. As the flocculant 115, for example, a polymer flocculant or the like is used.

  For this solid-liquid separation, a generally used thickener method is employed, and a countercurrent cleaning method using six or more thickeners can be used. Thus, the second neutralization solution containing nickel, cobalt, and magnesium in which the nickel and cobalt in the neutralization solution have a high yield of 99% by weight or more and the iron concentration is 1 g / l or less and the iron content is low. 113 and the second neutralization residue 114 are easily and efficiently separated into solid and liquid.

  The flocculant 115 may be a flocculant that can be separated into the second neutralization liquid 113 and the second neutralization residue 114, even if it is not a polymer flocculant.

  Moreover, you may perform solid-liquid separation into the 2nd neutralization liquid 113 and the 2nd neutralization residue 114 using another solid-liquid separation apparatus other than the countercurrent washing system by a six-stage or more thickener.

  The neutralization residue produced in the first neutralization step and the second neutralization step has good crystallinity, and because the solid-liquid separation is good because the particle size is large, the neutralization residue discharged from the lower part of the thickener The slurry concentration is improved. Therefore, a high yield of nickel and cobalt can be realized with a small amount of washing water. In addition, the scale of solid-liquid separation equipment such as thickener can be reduced, and the amount of equipment investment can be reduced. Furthermore, when the neutralization residue is deposited on the tailing pond as a slurry, the neutralization residue slurry has a high concentration. Therefore, the volume of the tailing pond required for depositing the neutralization residue slurry of the same weight is reduced. Can be reduced. Further, in the case of the same volume, the lifetime can be extended. Therefore, the amount of capital investment can be reduced.

  Moreover, when isolate | separating a neutralization residue slurry into a neutralization residue and a liquid using filtration apparatus like a filter press, the moisture content contained in solid can be decreased. For this reason, handling of the neutralized residue is facilitated. For example, when it is backfilled in a mine moat, transportation by an excavator or a truck is facilitated, and workability can be improved.

Step g: Solvent Extraction Step FIG. 3 illustrates a solvent extraction step for separating the second neutralization solution 113 into a nickel sulfate solution 130 and a cobalt sulfate solution 132 using an organic solvent 134 containing a monothiophosphinic acid group. FIG. In the present embodiment, a solvent extraction process including a five-stage extraction process, a two-stage back extraction process, and a one-stage washing process will be described. Here, the chemical formula of the organic solvent 134 containing a monothiophosphinic acid group is shown in the general formula (17).

R ₁ R ₂ PSOH (17)

In formula (17), R ₁ and R ₂ are each independently a hydrocarbon group which may have a substituent. The hydrocarbon group has more preferably 3 to 25 carbon atoms, and even more preferably 5 to 15 carbon atoms. Further, the hydrocarbon group may not have polarity. In addition, R ₁ and R ₂ may be the same hydrocarbon group or different hydrocarbon groups. Examples of the substituent include a halogen group, an oxy group, a carbonyl group, and an amide bond group. As the hydrocarbon group for R ₁ and R _2, a cycloalkyl group which may have a substituent, an aryl group which may have a substituent, a substituent which may have a straight chain or a side chain An aralkyl group, an alkyl group having a straight chain or a side chain, and an alkenyl group having a straight chain or a side chain can be used.

  Here, as the organic solvent 134, specifically, di- (2,4,4-trimethylpentyl) -monothiophosphinic acid, di- (2-ethylhexyl) -monothiophosphinic acid, di- -(N-octyl) -monothiophosphinic acid, di- (2-methyl-5-hexenyl) -monothiophosphinic acid, di- (p-methylcyclohexyl) -monothiophosphinic acid, di- (cyclohexyl) -mono Examples thereof include thiophosphinic acid, diphenylmonothiophosphinic acid, di- (p-ethylphenyl) -monothiophosphinic acid, di- (p-methylphenyl) -monothiophosphinic acid and the like.

  In the present embodiment, Cyanex (trademark) 302 (manufactured by Cyanamide) having di- (2,4,4-trimethylpentyl) -monothiophosphinic acid as a main component was used as the organic solvent 134. The chemical formulas of di- (2,4,4-trimethylpentyl) -monothiophosphinic acid constituting the main component of Cyanex ™ 302 (manufactured by Cyanamid Co.) are shown in the following formulas (15) and (16).

  RRPSOH (15)

R = CH ₃ C (CH ₃ ) ₂ CH ₂ CH (CH ₃ ) CH ₂ − (16)

  In this step, the cobalt component of the second neutralization liquid 113 supplied to the fifth extraction stage is extracted by an organic solvent 134 such as Cyanex (trademark) 302 (manufactured by Cyanamid Co.), which is an extraction solvent. As the transition proceeds, the cobalt content decreases, and the liquid that has passed through the first stage of extraction becomes a nickel sulfate solution 130 containing almost no cobalt. Here, the nickel sulfate solution 130 includes a magnesium component in the second neutralizing solution 113 and the like.

  On the other hand, an organic solvent 134 such as Cyanex (trademark) 302 (manufactured by Cyanamid Co.), which is an extraction solvent, extracts cobalt from the second neutralized solution 113 in the first to fifth extraction stages. Therefore, the cobalt content in the organic solvent 134 increases as the organic solvent 134 moves through the extraction stages. Next, the organic solvent 134 having a high cobalt content is mixed with sulfuric acid supplied to the second back extraction stage in the first and second back extraction stages, whereby cobalt is back extracted into the sulfuric acid, and the second back extraction stage. The organic solvent 134 that has passed through becomes an organic solvent 134 that hardly contains cobalt. Further, since cobalt is back-extracted in the sulfuric acid that has passed through the first stage of back extraction, a cobalt sulfate solution 132 containing almost no magnesium component or the like is obtained.

  In this step, nickel and cobalt can be efficiently separated and recovered by using an organic solvent 134 having a monothiophosphinic acid group such as Cyanex (trademark) 302 (manufactured by Cyanamid Co., Ltd.).

Step h: Solidification Step Nickel hydroxide 138 and cobalt hydroxide 140 are obtained by mixing alkali compound 136 with nickel sulfate solution 130 and cobalt sulfate solution 132, respectively. As the alkali compound, magnesium oxide, magnesium hydroxide, sodium hydroxide and the like can be used.

Step i: Sulfur / Chlorine Removal Step As shown in FIG. 2, the metal hydroxide 202 containing nickel or cobalt obtained in step h is slurried with water 205, mixed with sodium hydroxide 203 and stirred ( Mixing / stirring step (S91)). Here, in addition to sodium hydroxide 203, it may be mixed with sodium carbonate or a mixture of sodium hydroxide and sodium carbonate and stirred.

  By doing so, the sulfate radical and chlorine radical contained in the metal hydroxide 202 are removed, and the content of sulfur and chlorine contained in the metal hydroxide 202 can be reduced.

  The amount of sodium hydroxide 203 used is desirably 0.05 times or more and 1 time or less, and 0.1 times or more and 0.5 times or less the dry weight of the metal hydroxide 202. It is more desirable. That is, the amount of sodium hydroxide 203 used is preferably 5% by weight or more and 100% by weight or less of the dry weight of the metal hydroxide 202, and more preferably 10% by weight or more and 50% by weight or less.

  The removal effect of sulfur and chlorine contained in the metal hydroxide 202 can be improved by setting the weight preferably 0.05 times or more, more preferably 0.1 times or more. In addition, the production cost is preferably 1 times the weight or less, more preferably 0.5 times the weight or less, without greatly increasing the amount of sodium hydroxide 203 used while maintaining the effect of removing sulfur and chlorine. Can be suppressed.

  The mixing / stirring temperature is preferably 20 ° C. or higher and 100 ° C. or lower, and more preferably 50 ° C. or higher and 100 ° C. or lower.

  By mixing and stirring at a temperature of 20 ° C. or higher, preferably 50 ° C. or higher, the amount of sodium hydroxide 203 used can be reduced, and for example, metal hydroxide can be obtained by mixing and stirring for a short time such as about 30 minutes. Removal of sulfur and chlorine from the product 202 can be performed efficiently. By mixing and stirring at a temperature of 100 ° C. or lower, sulfur and chlorine can be removed without using a pressure vessel, and an increase in cost required for the equipment can be suppressed. Moreover, operation can be performed stably.

  After the slurry 204 thus obtained is filtered by a filter press or the like, the metal hydroxide 206 and sodium containing nickel or cobalt are washed by washing with water containing no sulfate or hydrochloric acid radicals such as river water. It is possible to obtain a solution 208 containing the solution (filtration and water washing step (S92)).

Slurry with a sodium hydroxide solution improves the crystallinity of nickel hydroxide and promotes recrystallization. Also, _{Ni (OH) 2 · 0.75H 2} O → Ni (OH) varies in _two crystal structure. This change in crystal structure leads to an increase in the nickel content of nickel hydroxide, and the nickel content of nickel hydroxide without the same weight of hydrate is equal to the nickel content of nickel hydroxide with hydrate. Increase in comparison.

  By mixing water 205, sodium hydroxide 203, and metal hydroxide 202, mixing and stirring as a slurry can not only remove sulfur and chlorine but also improve the nickel content of metal hydroxide 206. It becomes. In addition, the cobalt content of the metal hydroxide 206 can be improved.

Step j: Ferronickel production step As shown in FIG. 2, in this step, an oxide ore 218 containing iron and nickel, a metal hydroxide 206, and coal 210 are used as auxiliary materials. In addition, ferronickel is produced by a dry smelting method by reducing almost the entire amount of nickel and a part of iron using a kiln and an electric furnace.

  Here, the metal hydroxide 206 contains about 40 wt% or more and 50 wt% or less of adhering water. In this embodiment, the metal hydroxide 206 is mixed with the oxidized ore 218 and charged into the kiln to reduce (capacitor). Baked).

Sulfur and chlorine contained in the metal hydroxide 206 are almost entirely decomposed in the rotary kiln when the maximum temperature in the kiln is in the range of 600 ° C. to 1200 ° C., and as SO _x gas and Cl ₂ gas in the exhaust gas 216. Released. Therefore, it is possible to operate without increasing the concentration of SO _x and Cl ₂ gas in the exhaust gas 216 by using the metal hydroxide 206 containing nickel from which sulfur and chlorine have been removed in advance by the above-described method. it can. Therefore, it is not necessary to newly install an exhaust gas treatment facility, and the cost for investing in the facility can be reduced.

  Next, the reduced ore is melted by charging it into an electric furnace, and almost all the nickel contained in the reduced ore and a part of iron are reduced. By doing so, the purified ferronickel 212 can be taken out from the electric furnace. Further, slag 214 and exhaust gas 216 are discharged from the electric furnace.

  Ferronickel 212 taken out from the electric furnace is used as a raw material for stainless steel. Moreover, since slag contains many magnesium, it can also be used as a neutralizing agent in the process d.

  By the process described above, nickel and cobalt are efficiently recovered from the oxide ore containing nickel, cobalt and iron.

  Hereinafter, the effect of this embodiment will be described.

  In the method of recovering nickel or cobalt, low nickel high Mg oxide ore with low nickel grade and high magnesium grade is used effectively, while nickel in low Ni high Mg oxide ore is recovered and still exists in the reaction process. Free sulfuric acid is first neutralized with magnesium of low Ni high Mg oxide ore, and the free sulfuric acid is consumed to raise the pH of the neutralized solution, to precipitate and remove Fe to obtain a solution containing only a small amount of Fe. Thus, the processing cost for removing Fe is reduced, and at the same time, the productivity of nickel is increased more than ever.

Since the first neutralization reaction is a neutralization reaction between magnesium and free sulfuric acid in the oxide ore, it becomes a MgSO ₄ liquid, and does not produce a CaSO ₄ solid like the neutralization reaction with calcium and free sulfuric acid. In the removal of Fe precipitate, the precipitation reaction is slow, and an Fe precipitate having good crystallinity and a large particle size is obtained. Therefore, the solid-liquid separation property is improved in the subsequent solid-liquid separation step, and the operability (handling property) can be improved.

In the first neutralization reaction, as shown in the reaction formulas (4) and (8), free sulfuric acid still present in the reaction step reacts with MgO (magnesium oxide) and NiO (nickel oxide) in the oxide ore, At the same time as free sulfuric acid is consumed, nickel is recovered as nickel sulfate. In this case, MgSO ₄ and NiSO ₄ are both liquids as reactants and do not produce a solid. In addition, the neutralization reaction of the reaction formula (4) proceeds gradually due to the crystal structure of the oxide ore composed of complex oxide, so that free sulfuric acid is gradually consumed, and accordingly, the reaction formulas (9) and (10) Thus, Fe in the liquid is precipitated as goethite FeO (OH) or natrojarosite NaFe ₃ (SO ₄ ) ₂ (OH) _{6 and} removed as a neutralization residue. Since the neutralization residue with a moderately advanced reaction has good crystallinity and a large particle size, the solid-liquid separation property is improved when, for example, a thickener is used in the solid-liquid separation step after the second neutralization step. In addition, the slurry concentration of the residue settled in the lower portion can be increased, the thickener capacity can be reduced, and at the same time, the operability (handling property) can be improved.

  Further, when the slurry concentration of the neutralization residue increases, the amount of nickel contained in the liquid removed from the neutralization residue decreases, and the nickel recovery rate can be improved with a small amount of washing water.

  Further, conventionally, a saprolite ore layer having a nickel component of 2% by weight or less has been left in the ore deposit without being mined, or it has been excluded from mine development from the beginning, and has not been used effectively. In the present embodiment, by using the low-grade Ni saprolite ore, which has not been used so far, for neutralizing the liquid in the hydrometallurgical process, it is possible to use all the nickel oxide ores of the nickel oxide ore deposits. can do.

  The preferred embodiments of the invention have been described above. However, the present invention is not limited to the above-described embodiments, and it goes without saying that those skilled in the art can modify the above-described embodiments within the scope of the present invention.

  For example, in this embodiment, although the form which provides the process a which classifies the oxide ore 102 containing nickel, cobalt, and iron was demonstrated, you may abbreviate | omit this process.

  Moreover, in this embodiment, although the 1st neutralization process (process d) was provided between the reaction process (process c) and the 2nd neutralization process (process e), a leaching process (process b) and You may provide between reaction processes (process c).

  Moreover, in this embodiment, although the form which performs pH adjustment by the process c using the oxide ore containing the oversized magnesium classified by the process a was demonstrated, for example, the nickel content rate is 1 weight% or less, Oxide ore having a magnesium content of 15% by weight or more and usually not used for recovering nickel and cobalt and having a relatively low nickel quality and a high magnesium quality may be used. Such oxide ores are often present in, for example, deep layers of nickel and cobalt mines, and have a feature that the iron content is relatively low. Therefore, by using the oxide ore in the step c, it is possible to adjust the pH with magnesium while leaching nickel and cobalt into the sulfuric acid solution, and to suppress an increase in the amount of iron leaching. As a result, the recovery cost of nickel and cobalt can be reduced while suppressing the decrease in the recovery rate of nickel and cobalt. Moreover, you may use what contains magnesium even if it is other than an oxide ore.

  Moreover, in the said embodiment, although the form which collect | recovers nickel and cobalt from the oxide ore 102 containing nickel, cobalt, and iron was demonstrated, nickel may be collect | recovered from the oxide ore containing nickel and iron, and cobalt Cobalt may be recovered from the oxide ore containing iron and iron.

  Moreover, when performing pH adjustment by the process c, an oxide ore having a low nickel quality and a high magnesium quality may be used together with the oxidized ore containing oversized magnesium classified in the process a.

  Moreover, when adjusting pH by the process c, you may use what contains magnesium other than an oxide ore with the oxide ore containing the oversized magnesium classified by the process a.

  Moreover, when performing pH adjustment by the process c, while using the oxide ore with the said nickel quality low and magnesium quality high, you may use what contains magnesium other than an oxide ore.

  In addition, when performing pH adjustment in step c, an oxide ore containing oversized magnesium classified in step a, an oxide ore having a low nickel quality and a high magnesium quality, and containing magnesium other than the oxide ore You may use together.

  Alternatively, the solution 208 containing sodium may be reused in the step b (leaching step), and nickel and cobalt may be leached from the oxidized ore 102 using the oxidized ore 102, the sulfuric acid 105, and the solution 208. By doing so, the leaching rate of iron from the oxide ore 102 in the leaching step is further controlled, and the iron concentration in the sulfuric acid leaching solution 108 can be reduced and the leaching rates of nickel and cobalt can be further improved. .

  In step b or step c, the leaching rate of nickel and cobalt may be further improved by using a reducing agent such as iron or sodium sulfite.

  Here, as the reducing agent, for example, iron powder, sodium sulfite, or a mixture thereof is used. When iron powder is used, it can be added in the range of 0.1 wt% to 1 wt%, particularly 0.2 wt% to 0.5 wt% with respect to the amount of oxide ore 102 used. Here, as the particle size of the iron powder, those having a diameter of about 1 mm can be used, and those whose surface is not oxidized can be used. Moreover, when using sodium sulfite, it can be made into the range of 1 to 10 weight% with respect to the usage-amount of the oxide ore 102, especially 5 to 8 weight%.

  By adding the reducing agent within the above range, it is possible to fully demonstrate the effect of the reducing agent, and due to the synergistic effect with the control of the iron concentration in other processes, the leaching rate of nickel and cobalt, especially the leaching of cobalt The rate can be further improved efficiently. Therefore, the recovery rate of nickel and cobalt can be further improved while reducing the cost of removing iron.

  The reason why the addition of the reducing agent is effective in improving the leaching rate of nickel and cobalt, particularly the leaching rate of cobalt, is considered as follows.

That is, the cobalt in the oxide ore 102 exists in the form of a divalent oxide (CoO) and a trivalent oxide (Co ₂ O ₃ ), and the abundance ratio is presumed to be different depending on the ore production area. . Co ₂ O ₃ is stronger and more stable than CoO in such a bonding state between cobalt and oxygen, and the sulfuric acid 105 causes the coupling between cobalt and oxygen in the trivalent cobalt oxide contained in the slurry ore 104. It is not easy to break. Therefore, by adding a reducing agent in addition to sulfuric acid 105, the binding force between cobalt and oxygen in the trivalent cobalt oxide is weakened, and the valence of cobalt is reduced from trivalent to divalent. It is presumed that leaching has become easier.

  Examples of the present invention will be specifically described below. Here, Experimental Example A-1 and Experimental Example B-1 are comparative examples, and Experimental Example A-2, Experimental Example A-3, Experimental Example B-2, and Experimental Example B-3 are Examples.

  Tables 2 to 5 show the experimental conditions and experimental results of Experimental Example A-1 to Experimental Example A-3 and Experimental Example B-1 to Experimental Example B-3.

(Experimental example A-1)
In this experimental example, Ni: 1.58 wt%, Co: 0.078 wt%, Fe: 24.5 wt%, Mg: 9.5 wt% were contained, and Mg / Fe ratio: 0.00. 39 oxide ores were used. This oxide ore was classified with a 2 mm sieve to obtain 72.5 wt% of −2 mm oxide ore and 27.5 wt% of +2 mm oxide ore. The +2 mm oxide ore was crushed into a total amount of -2 mm ore. -2mm oxide ore is made 28% by weight slurry ore by adding seawater, and 98% by weight sulfuric acid is added 0.73 times weight (73% by weight) with respect to the total oxidized ore before classification, The mixture was stirred and leached for 6 hours at a temperature of 95 ° C. and atmospheric pressure.

  To the sulfuric acid leaching solution and the leaching residue obtained in this manner, the oxidized ore made into a slurry ore having a concentration of 40% by weight by adding seawater to the pulverized product of +2 mm oxidized ore was added, and the temperature was 95 ° C. under atmospheric pressure. And reacted for 5 hours. The leaching rate after the normal pressure reaction was examined. As a result, Ni was 89% by weight, Co was 60% by weight, Fe was 14.9% by weight, and Mg was 71.6% by weight. Concentration: 12.51 g / l, Fe / Ni concentration ratio: 2.49, free sulfuric acid content: 35 g / l, and the leaching rate of nickel and cobalt was good, but iron and free sulfuric acid were the reaction solution at atmospheric pressure A large amount remained in it. Limestone as a neutralizing agent was added to the reaction solution and the reaction residue thus obtained at a temperature of 90 ° C. until the pH became 3.3, and then the mixture was held with stirring. The time from the addition to the stirring and holding was 2 hours.

  The amount of limestone used was 0.18 times the weight (18% by weight) with respect to the total amount of oxidized ore before classification. The amount of neutralization residue after neutralization with limestone was 1.3 times the weight (130% by weight) of the total oxide ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction.

  Next, a polymer flocculant is added to the neutralized solution and the neutralized residue, the neutralized residue is aggregated and allowed to settle naturally, and then the neutralized solution and the neutralized residue are separated using a countercurrent washing type six-stage thickener. Solid-liquid separation. When the concentration of the concentrated slurry neutralization residue settled at the bottom was examined, it was 29.5% by weight. Furthermore, when this concentrated slurry was filtered with a vacuum filtration device, the water content of the neutralized residue was 47.8% by weight.

  Next, using an organic solvent as an extraction solvent, nickel and cobalt contained in the neutralization solution were separated into a nickel sulfate solution and a cobalt sulfate solution (solvent extraction step). Next, nickel hydroxide and cobalt hydroxide were obtained by mixing magnesium hydroxide into the nickel sulfate solution and the cobalt sulfate solution (solidification step). Next, nickel or cobalt from which sulfur or chlorine has been removed by mixing, stirring, filtering and washing with water, metal hydroxide containing nickel or cobalt in a slurry state, and sodium hydroxide is mixed and stirred. A metal hydroxide and a solution were obtained (sulfur / chlorine removal step). Next, metal hydroxide, nickel-containing saprolite ore, and coal were mixed and reduced (calcined) with a rotary kiln. Next, the reduced mixture was charged into an electric furnace and melted to obtain ferronickel (ferronickel production process).

(Experimental example A-2)
After performing the normal pressure leaching and the normal pressure reaction under the same conditions as in Experimental Example A-1, as a preliminary neutralization step, prior to limestone neutralization, Ni: 1.25 wt%, Co: 0.012 wt%, Fe : 5.9 wt%, Mg: 16.9 wt%, Mg / Fe: 2.86 Nickel ore and low magnesium grade ore (low Ni grade saprolite ore) is crushed to -2 mm or less In addition, slurry ore with a concentration of 40% by weight was added, and 0.2 times the weight (20% by weight) of the total oxide ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction was added. Stirred (first neutralization step). Here, the low Ni grade saprolite ore used in this example is a composite oxide having MgO.SiO ₂ and FeO (OH) as components.

  The Fe concentration of the first neutralized solution was 1.84 g / l, the Fe / Ni concentration ratio was 0.36, and the pH of the solution was 1.77. The nickel leaching rate calculated from the difference between the amount of nickel in the first neutralization solution and the amount of nickel in the reaction solution and the amount of nickel in the low Ni high Mg oxide ore used in the first neutralization step was 80.6. The magnesium leaching rate calculated in the same manner was 58.6% by weight.

  Further, the Fe removal rate calculated from the difference between the amount of Fe in the first neutralized solution and the amount of Fe in the reaction solution is 84% by weight, and the first neutralization step recovers nickel from the low Ni high Mg oxide ore. It was found that precipitation of Fe in the reaction solution was performed efficiently.

Further, when the first neutralization residue was examined by X-ray diffraction, the crystal structure of natrojarosite NaFe ₃ (SO ₄ ) ₂ (OH) ₆ was identified as an Fe precipitate. From the crystal strength, it was found that the crystal was very good. (See Figure 5)

  After adding limestone as a neutralizing agent to the first neutralization solution and the first neutralization residue thus obtained at a temperature of 90 ° C. until the pH becomes 3.3, the mixture is kept under stirring, A neutralization step was performed. The time from the addition to the stirring and holding was 2 hours.

  The amount of limestone used was 0.07 times the weight (7% by weight) of the total amount of oxidized ore before classification, and the amount of limestone used was significantly reduced as compared with Experimental Example A-1.

  The amount of the second neutralization residue after neutralization with limestone was 1.27 times the weight of the total oxidized ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction. Next, a polymer flocculant is added to the second neutralization liquid and the second neutralization residue, the second neutralization residue is agglomerated and allowed to settle naturally, and then the second medium is obtained using a countercurrent washing type six-stage thickener. Solid-liquid separation was performed between the Japanese liquid and the second neutralization residue. The concentration of the concentrated slurry-like second neutralization residue that settled at the bottom was 41.9% by weight, which was a significant increase in slurry concentration as compared with Experimental Example A-1. Furthermore, when the concentrated slurry was filtered with a vacuum filtration device, the water content of the second neutralized residue was 28.5% by weight, and the water content was greatly reduced as compared with Experimental Example A-1. In addition, the settling time in the thickener during the solid-liquid separation could be shortened.

  Next, nickel and cobalt contained in the second neutralization liquid were separated into a nickel sulfate solution and a cobalt sulfate solution using an organic solvent which is an extraction solvent (solvent extraction step). Next, nickel hydroxide and cobalt hydroxide were obtained by mixing magnesium hydroxide into the nickel sulfate solution and the cobalt sulfate solution (solidification step). Next, nickel or cobalt from which sulfur or chlorine has been removed by mixing, stirring, filtering and washing with water, metal hydroxide containing nickel or cobalt in a slurry state, and sodium hydroxide is mixed and stirred. A metal hydroxide and a solution were obtained (sulfur / chlorine removal step). Next, metal hydroxide, nickel-containing saprolite ore, and coal were mixed and reduced (calcined) with a rotary kiln. Next, the reduced mixture was charged into an electric furnace and melted to obtain ferronickel (ferronickel production process).

(Experimental example A-3)
Oxide ore with low nickel grade and high magnesium grade (low Ni grade saprolite ore) added 0.3 times weight (30 wt%) to the total oxide ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction Except having performed the 1st neutralization process, it implemented on the same conditions as Experimental example A-2. The Fe concentration of the first neutralized solution was 0.45 g / l, the Fe / Ni concentration ratio was 0.09, and the pH of the solution was 2.12. The nickel leaching rate calculated from the difference between the amount of nickel in the first neutralization solution and the amount of nickel in the reaction solution and the amount of nickel in the low Ni high Mg oxide ore used in the first neutralization step was 78.1. The magnesium leaching rate calculated in the same manner was 48.1% by weight. Further, the Fe removal rate calculated from the difference between the amount of Fe in the first neutralization solution and the amount of Fe in the reaction solution is 96% by weight. By the first neutralization step, the nickel content of the low Ni high Mg oxide ore is reduced. It was found that the recovery and the Fe precipitation in the reaction solution were performed efficiently.

  After adding limestone as a neutralizing agent to the first neutralization solution and the first neutralization residue thus obtained at a temperature of 90 ° C. until the pH becomes 3.3, the mixture is kept stirred and second neutralized. The process was performed. The time from the addition to the stirring and holding was 2 hours.

  The amount of limestone used was 0.04 times the weight (4% by weight) of the total amount of oxidized ore before classification, and the amount of limestone used was significantly reduced compared to Experimental Example A-1.

  The amount of the second neutralization residue after limestone neutralization was 1.3 times the weight of the total oxidized ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction.

  Next, a polymer flocculant is added to the second neutralization liquid and the second neutralization residue, the second neutralization residue is agglomerated and allowed to settle naturally, and then the second medium is obtained using a countercurrent washing type six-stage thickener. Solid-liquid separation was performed between the Japanese liquid and the second neutralization residue. When the concentration of the concentrated slurry-like second neutralization residue settled at the lower portion was examined, the concentration was 42.3 wt%, and the slurry concentration was significantly improved as compared with Experimental Example A-1. Furthermore, when this concentrated slurry was filtered with a vacuum filtration device, the water content of the second neutralization residue was 27.1% by weight, and the water content was greatly reduced as compared with Experimental Example A-1. In addition, the settling time in the thickener during the solid-liquid separation could be shortened.

(Experimental example B-1)
In this experimental example, Ni: 1.98% by weight, Co: 0.063% by weight, Fe: 23.1% by weight, Mg: 9.2% by weight, and Mg / Fe ratio: 0. The test was carried out under the same conditions as in Experimental Example A-1, except that 40 oxide ores were used.

  When the leaching rate after the normal pressure reaction was examined, Ni was 90.1% by weight, Co: 77.6% by weight, Fe: 11.8% by weight, and Mg: 80.9% by weight. The subsequent Fe concentration: 9.52 g / l, Fe / Ni concentration ratio: 1.61, free sulfuric acid content: 30 g / l, and the leaching rate of nickel and cobalt was good, but iron and free sulfuric acid were usually used. A large amount remained in the pressurized liquid.

  Limestone as a neutralizing agent was added to the reaction solution and the reaction residue thus obtained at a temperature of 90 ° C. until the pH became 3.3, and then the mixture was held with stirring. The time from the addition to the stirring and holding was 2 hours.

  The amount of limestone used was 0.15 times (15% by weight) the total amount of oxidized ore before classification. The amount of residue after neutralization with limestone was 1.24 times the weight of the total oxide ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction.

  Next, a polymer flocculant is added to the neutralized solution and the neutralized residue, the neutralized residue is aggregated and allowed to settle naturally, and then the neutralized solution and the neutralized residue are separated using a countercurrent washing type six-stage thickener. Solid-liquid separation. When the concentration of the concentrated slurry neutralization residue settled at the bottom was examined, it was 32.1% by weight. Furthermore, when this concentrated slurry was filtered with a vacuum filtration device, the water content of the neutralized residue was 45.1% by weight.

(Experimental example B-2)
Normal pressure leaching and normal pressure reaction were carried out under the same conditions as in Experimental Example B-1, and prior to limestone neutralization, Ni: 1.43% by weight, Co: 0.011% by weight, Fe: 7.8% by weight %, Mg: 18.1 wt%, Mg / Fe: 2.32 nickel ore and high magnesium grade oxide ore (low Ni grade saprolite ore) is crushed to -2 mm or less, and seawater is added to 40 wt% Add 0.2 times weight (20% by weight) of the total ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction, and stir at 95 ° C for 3 hours. A neutralization step was performed.

  The Fe concentration of the first neutralization liquid was 2.88 g / l, the Fe / Ni concentration ratio was 0.47, and the pH of the liquid was 1.85. The nickel leaching rate calculated from the difference between the amount of nickel in the first neutralization solution and the amount of nickel in the reaction solution and the amount of nickel in the low Ni high Mg oxide ore used in the first neutralization step was 78.2. The magnesium leaching rate calculated in the same manner was 56.1% by weight.

  The Fe removal rate calculated from the difference between the amount of Fe in the first neutralized solution and the amount of Fe in the reaction solution is 70.1% by weight, and the first neutralization step recovers nickel from the low Ni high Mg oxide ore. It was found that Fe precipitation in the reaction solution was performed efficiently.

Further, when the first neutralization residue was examined by X-ray diffraction, the crystal structure of natrojarosite NaFe ₃ (SO ₄ ) ₂ (OH) ₆ was identified as an Fe precipitate. From the crystal strength, it was found that the crystal was very good.

  After adding limestone as a neutralizing agent to the first neutralization solution and the first neutralization residue thus obtained at a temperature of 90 ° C. until the pH becomes 3.3, the mixture is stirred and retained. The sum process was performed. The time from the addition to the stirring and holding was 2 hours.

  The amount of limestone used was 0.07 times (7% by weight) of the total amount of oxidized ore before classification, and the amount of limestone used was significantly reduced compared to Experimental Example B-1.

  The amount of the second neutralization residue after limestone neutralization was 1.21 times the weight of the total oxide ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction.

  Next, a polymer flocculant is added to the second neutralization liquid and the second neutralization residue, the second neutralization residue is agglomerated and allowed to settle naturally, and then the second medium is obtained using a countercurrent washing type six-stage thickener. Solid-liquid separation was performed between the Japanese liquid and the second neutralization residue. The concentration of the concentrated slurry-like second neutralization residue that settled at the bottom was 43.9% by weight, which greatly increased the slurry concentration as compared with Experimental Example B-1. Furthermore, when the concentrated slurry was filtered with a vacuum filtration device, the water content of the second neutralization residue was 27% by weight, and the water content was greatly reduced as compared with Experimental Example B-1. In addition, the settling time in the thickener during the solid-liquid separation could be shortened.

  Next, nickel and cobalt contained in the second neutralization liquid were separated into a nickel sulfate solution and a cobalt sulfate solution using an organic solvent which is an extraction solvent (solvent extraction step). Next, nickel hydroxide and cobalt hydroxide were obtained by mixing magnesium hydroxide into the nickel sulfate solution and the cobalt sulfate solution (solidification step). Next, nickel or cobalt from which sulfur or chlorine has been removed by mixing, stirring, filtering and washing with water, metal hydroxide containing nickel or cobalt in a slurry state, and sodium hydroxide is mixed and stirred. A metal hydroxide and a solution were obtained (sulfur / chlorine removal step). Next, metal hydroxide, nickel-containing saprolite ore, and coal were mixed and reduced (calcined) with a rotary kiln. Next, the reduced mixture was charged into an electric furnace and melted to obtain ferronickel (ferronickel production process).

(Experimental example B-3)
Oxide ore with low nickel grade and high magnesium grade (low Ni grade saprolite ore) added 0.3 times weight (30 wt%) to the total oxide ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction Except having performed the 1st neutralization process, it implemented on the same conditions as Experimental example B-2.

  The Fe concentration of the first neutralized solution was 0.48 g / l, the Fe / Ni concentration ratio was 0.08, and the pH of the solution was 2.35. The nickel leaching rate calculated from the difference between the amount of nickel in the first neutralization solution and the amount of nickel in the reaction solution and the amount of nickel in the low Ni high Mg oxide ore used in the first neutralization step was 72.5. The magnesium leaching rate calculated in the same manner was 45.9% by weight. Moreover, the Fe removal rate calculated from the difference between the amount of Fe in the first neutralization solution and the amount of Fe in the reaction solution is 93.4% by weight. It was found that nickel recovery and Fe precipitation in the reaction solution were performed efficiently.

  After adding limestone as a neutralizing agent to the first neutralization solution and the first neutralization residue thus obtained at a temperature of 90 ° C. until the pH becomes 3.3, the mixture is stirred and retained. The sum process was performed. The time from the addition to the stirring and holding was 2 hours.

  The amount of limestone used was 0.04 times (4% by weight) of the total amount of oxidized ore before classification, and the amount of limestone used was significantly reduced compared to Experimental Example B-1.

  The amount of the second neutralization residue after limestone neutralization was 1.23 times the weight of the total oxide ore before classification used for atmospheric pressure leaching and atmospheric pressure reaction.

  Next, a polymer flocculant is added to the second neutralization liquid and the second neutralization residue, the second neutralization residue is agglomerated and allowed to settle naturally, and then the second medium is obtained using a countercurrent washing type six-stage thickener. Solid-liquid separation was performed between the Japanese liquid and the second neutralization residue. The concentration of the concentrated slurry-like second neutralization residue settled at the bottom was 43.5% by weight, and the slurry concentration was significantly increased as compared with Experimental Example B-1. Furthermore, when the concentrated slurry was filtered with a vacuum filtration device, the water content of the second neutralization residue was 26.3% by weight, and the water content was greatly reduced as compared with Experimental Example B-1. In addition, the settling time in the thickener during the solid-liquid separation could be shortened.

It is a flowchart for demonstrating the manufacturing process which concerns on embodiment. It is a flowchart for demonstrating the manufacturing process which concerns on embodiment. It is a flowchart for demonstrating the manufacturing process which concerns on embodiment. It is the schematic of the deposit distribution of the nickel oxide ore which concerns on embodiment. It is a figure for demonstrating the X-ray-diffraction result of the sample which concerns on an experiment example.

Explanation of symbols

102 Oxide ore 103 Ground product 104 Slurry ore 105 Sulfuric acid 106 Sodium salt 107 Water 108 Sulfuric acid leaching solution 109 Leaching residue 110 Reaction solution 111 Reaction residue 112 Neutralizing agent 113 Second neutralizing solution 114 Second neutralizing residue 115 Flocculant 130 Nickel sulfate Solution 132 Cobalt sulfate solution 134 Organic solvent 136 Alkaline compound 138 Nickel hydroxide 140 Cobalt hydroxide 202 Metal hydroxide 203 Sodium hydroxide 205 Water 206 Metal hydroxide 208 Solution 210 Coal 212 Ferronickel 214 Slag 216 Exhaust gas 218 Oxidation Ore 300 Oxide ore 302 First neutralization liquid 304 First neutralization residue

Claims (17)

A method for recovering nickel or cobalt from a first oxide ore containing nickel or cobalt and iron,
A leaching step of leaching nickel or cobalt from the first oxide ore using sulfuric acid to obtain a sulfuric acid leaching solution containing nickel or cobalt, and a leaching residue;
Reacting the sulfuric acid leaching solution containing the leaching residue with magnesium to adjust the pH to obtain a reaction liquid containing nickel or cobalt and a reaction residue containing iron; and
Liquid obtained in the reaction step using a low Ni grade saprolite ore having a Ni content of 2% by weight or less, a Fe content of 20% by weight or less, and a Mg content of 15% by weight or more. A pre-neutralization step of increasing the pH of
The liquid obtained in the preliminary neutralization step is neutralized using a neutralizing agent other than the low Ni grade saprolite ore, a neutralization liquid containing nickel or cobalt, and a neutralization residue containing iron. Obtaining a neutralization step;
The collection method characterized by including. The recovery method according to claim 1,
The neutralizing agent is sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, ferronickel slag, or slag containing magnesium. A recovery method comprising at least one. In the collection method according to claim 1 or 2,
Before the leaching process,
Including a classification step of classifying the first oxide ore into a small particle size oxide ore and a large particle size oxide ore containing magnesium;
In the leaching step, leaching nickel or cobalt from the small particle size oxidized ore,
In the reaction step, the sulfuric acid leaching solution containing the leaching residue is reacted with magnesium contained in the large particle size oxidized ore to adjust pH,
The magnesium content rate of said 2nd oxide ore is higher than the magnesium content rate of the said large-particle-size oxide ore, The recovery method characterized by the above-mentioned. The recovery method according to claim 3,
The nickel oxide content of the second oxide ore is lower than the nickel content of the large particle size oxide ore. The recovery method according to any one of claims 1 to 4,
In the leaching step, further using a sodium salt, leaching nickel or cobalt from the first oxide ore to obtain a sulfuric acid leaching solution containing nickel or cobalt, and a leaching residue,
In the reaction step, the sulfuric acid leaching solution containing the leaching residue is pH-adjusted to obtain a reaction solution containing nickel or cobalt and a reaction residue. The recovery method according to claim 5,
The recovery method, wherein the sodium salt is a sodium salt contained in seawater. The recovery method according to claim 5,
The recovery method, wherein the sodium salt is a sodium salt contained in concentrated seawater. The collection method according to claim 7,
The concentration method of the sodium salt contained in the said concentrated seawater is 4 to 5.3 weight%, The collection method characterized by the above-mentioned. The recovery method according to any one of claims 5 to 8,
The use amount of the sodium salt is 1% by weight or more and 5% by weight or less of the use amount of the first oxide ore. The recovery method according to any one of claims 1 to 9,
In the leaching step, further using a reducing agent, nickel or cobalt is leached from the first oxide ore, and a sulfuric acid leaching solution containing nickel or cobalt and a leaching residue are obtained. . The recovery method according to claim 10,
The recovery method, wherein the reducing agent is iron powder. The collection method according to any one of claims 1 to 11,
A recovery method characterized in that both the leaching step and the reaction step are performed at a temperature of 90 ° C. or higher. The recovery method according to any one of claims 1 to 12,
A recovery method characterized by performing both the leaching step and the reaction step under normal pressure. The recovery method according to any one of claims 1 to 13,
After the neutralization step, the neutralization liquid and the neutralization residue are separated into solid and liquid using a flocculant and a thickener to separate the neutralization liquid and the neutralization residue. The collection | recovery method characterized by further including a process. The collection method according to any one of claims 1 to 14,
A recovery method, wherein the preliminary neutralization step is performed at a temperature of 90 ° C. or higher. The recovery method according to any one of claims 1 to 15,
In the leaching step, the use amount of the sulfuric acid is 50% by weight or more and 80% by weight or less of the use amount of the first oxide ore. The recovery method according to any one of claims 1 to 16,
In the preliminary neutralization step, the pH of the liquid is adjusted to 1 or more and 4 or less.

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