JP5530195B2 - Method for recovering copper from copper-containing material - Google Patents

Description

  The present invention relates to a method for recovering copper by treating moss and the like containing copper.

  Copper-containing dross generated by lead smelting exists in the form of a Cu-Sn alloy or the like. Substances contained in copper-containing dross, including this alloy, are hardly soluble and difficult to process. However, the copper grade in the copper-containing dross is as high as about 20%, and it is desired to recover copper from the copper-containing dross from the viewpoint of resource saving and environmental conservation.

  As a method for recovering valuable metals from copper-containing dross, a hot concentrated sulfuric acid method and an alkali melting method are known. For example, regarding the hot concentrated sulfuric acid method, in Patent Document 1, refined dross generated in a dry process of lead smelting and concentrated sulfuric acid having a concentration of 96% are mixed and heated to 160 ° C. to obtain a slurry. It is described that leaching is performed by adding water and dilute sulfuric acid aqueous solution to the slurry after cooling. This document states that 89.2% of the copper contained in the dross was leached by this treatment.

  With respect to the alkali melting method, Patent Document 2 discloses that a compound containing copper and tin as constituent components and a mixture containing lead are mixed with an alkali hydroxide molten bath, and tin in the mixture is mixed in the molten bath. Obtaining an alkali hydroxide mixture by extraction into water; mixing the water with water to reduce the alkali hydroxide concentration to obtain a slurry containing tin and a residue containing copper and lead; and the slurry; Describes a method for recovering a metal having a step of separating a tin solution and a residue.

JP 2006-45588 A JP 2006-322031 A

  However, in the hot concentrated sulfuric acid method described in Patent Document 1, since concentrated sulfuric acid is used literally, it is necessary to take measures for preventing corrosion and preventing mist. In addition, since leaching and filtration are performed after cooling after heating, the entire process takes time and the number of processes increases. Moreover, the leaching process itself takes time.

  In the alkali melting method described in Patent Literature 2, an excessive amount of alkali hydroxide such as sodium hydroxide or potassium hydroxide is required, resulting in high cost.

  An object of the present invention is to provide a method for recovering copper from a copper-containing object to be processed, which can eliminate the various disadvantages of the above-described prior art.

The present invention, an object to be processed containing oxygen-free copper compound slightly soluble in gas phase oxidation, metallic copper or the acid Motohi containing copper compound to produce a cuprous oxide, and then the after gas phase oxidation process by applying an aqueous solution containing ammonia to be treated, copper is to provide a copper recovery method of copper-containing article to be treated, characterized in that recovered without the form of a soluble salt.

  According to the present invention, copper can be easily and quickly recovered from a copper-containing workpiece.

FIG. 1 is an XRD diffractogram of copper-containing dross used in Examples and Comparative Examples. FIG. 2 is an XRD diffractogram after vapor phase oxidation of the copper-containing dross shown in FIG. FIG. 3 is an XRD diffractogram after vapor phase oxidation of the copper-containing dross shown in FIG. FIG. 4 is a graph showing the relationship between the gas phase oxidation conditions and the copper leaching rate.

  Hereinafter, the present invention will be described based on preferred embodiments thereof. Examples of the object to be treated in the copper recovery method of the present invention include copper-containing dross and mats generated in lead smelting. Moreover, it is good also considering the lead ore (for example, galena) containing copper and the lead sulfide containing copper as a to-be-processed object depending on the case. Furthermore, waste lead batteries containing a sparingly soluble oxygen-free copper compound, metal scrap, sludge, steelmaking dust, waste, waste acid, waste alkali, soot and the like may be used as objects to be treated.

The oxygen-free copper compound contained in the object to be processed is hardly soluble. Here, the poor solubility means (i) not soluble in an acid of 0.1 N or less, (ii) not soluble in an alkali of 0.1 N or less, or (iii) 0.1 mol / liter or less. It is not soluble in an aqueous solution containing ammonium ions. Examples of such hardly soluble oxygen-free copper compounds include compounds of Cu and at least one element selected from Sn, Sb, S and Se. Specifically, a compound containing Cu and Sn such as Cu ₃ Sn, a compound containing Cu and S such as CuS, a compound containing Cu and Se, a compound containing Cu, Sb and Sn, a mixture of these compounds, etc. Can be mentioned.

  In the method of the present invention, first, the object to be treated is vapor-phase oxidized. In some cases, prior to vapor phase oxidation, the object to be treated may be pulverized to a predetermined size to promote vapor phase oxidation. For the gas phase oxidation, an oxygen-containing atmosphere such as oxygen itself or air is used. From the viewpoint of economy and the like, it is advantageous to use air. The gas phase oxidation can be performed in a stationary baking furnace such as a conveyor baking furnace, or a rotary baking furnace such as a drum furnace or a rotary kiln.

The gas phase oxidation is performed for the purpose of oxidizing the oxygen-free copper compound contained in the workpiece. Metallic copper, copper oxide (CuO) or cuprous oxide (Cu ₂ O) is produced by vapor phase oxidation of the oxygen-free copper compound. The temperature of the gas phase oxidation is appropriately set to a temperature at which these substances are generated. The specific temperature of the gas phase oxidation varies depending on the type of the oxygen-free copper compound and the like. For example, when copper-containing dross containing Cu ₃ Sn produced by lead smelting is oxidized in the atmosphere. The processing temperature is preferably set to 400 to 700 ° C, particularly 500 to 700 ° C.

When oxidizing an oxygen-free copper compound, the product changes depending on the degree of oxidation of the compound. For example, when copper-containing dross containing Cu ₃ Sn produced by lead smelting is oxidized in the air atmosphere, when the degree of oxidation is low, metallic copper or sub-oxide according to the following reaction formulas (1) and (2) Copper is produced.
Cu ₃ Sn + O ₂ → SnO ₂ + 3Cu (1)
Cu ₃ Sn + (7/4) O ₂ → SnO ₂ + (3/2) Cu ₂ O (2)
On the other hand, when the degree of oxidation is high, copper oxide is generated according to the following reaction formula (3).
Cu ₃ Sn + (5/2) O ₂ → SnO ₂ + 3CuO (3)

  Whether the reactions of formulas (1) and (2) or the formula (3) occur depends on the amount of oxygen supplied into the system. In general, when the amount of oxygen supplied is small, the reactions of formulas (1) and (2) occur preferentially. When the amount of oxygen supplied is large, the reaction of formula (3) occurs preferentially. Depending on the conditions of the oxidation treatment, the reactions of formulas (1) to (3) may occur simultaneously.

  The metal which is soluble in an aqueous solution containing sulfuric acid or ammonia (hereinafter referred to as “ammonia-containing liquid”) is obtained by vapor-phase oxidation of the object to be processed. It has changed to copper, copper oxide or cuprous oxide. Then, sulfuric acid or ammonia containing liquid is made to act on the to-be-processed object after completion | finish of oxidation treatment, and these metal copper etc. are dissolved in water. The oxygen-free copper compound contained in the object to be treated before the oxidation treatment is hardly soluble, and it does not dissolve even if a sulfuric acid or ammonia-containing liquid is directly applied to this, but by performing the above oxidation treatment It will dissolve.

  Which of sulfuric acid and ammonia-containing liquid is allowed to act on the workpiece after the oxidation treatment is determined depends on the degree of oxidation of the workpiece. When the degree of oxidation of the object to be treated is low and the product of oxidation is mainly copper and / or cuprous oxide, it is preferable to use an ammonia-containing liquid which is a substance that easily dissolves these. On the other hand, when the degree of oxidation of the object to be treated is high and the product resulting from the oxidation is mainly copper oxide, it is preferable to use sulfuric acid, which is a substance that easily dissolves the copper oxide. Although copper oxide can be dissolved by an ammonia-containing liquid, since it takes a long time to dissolve, sulfuric acid is used for dissolving copper oxide in the present invention.

  In the case of using an ammonia-containing liquid, the object to be treated after the oxidation treatment and the ammonia-containing liquid may be mixed and stirred. The concentration of ammonia in the ammonia-containing liquid is preferably 0.5 to 10 mol / liter, particularly 2 to 5 mol / liter from the viewpoint of efficient dissolution of copper and / or cuprous oxide. The mixing and stirring of both may be performed at room temperature (20 to 25 ° C.) or may be performed under heating. In the case of heating, heating to about 60 to 80 ° C. is preferable from the viewpoint of promoting dissolution. When the ammonia concentration in the ammonia-containing liquid is within the above range, the mixing ratio of the ammonia-containing liquid and the object to be processed after the oxidation treatment is as follows. The ammonia-containing liquid is preferably 1 liter to 50 liters, particularly 5 liters to 20 liters. By dissolution using an ammonia-containing liquid, a copper ammine complex, which is a soluble compound, is produced in water.

  As the ammonia-containing liquid, for example, aqueous ammonia can be used. In this case, the object to be treated can be dissolved by suspending the object to be treated after the oxidation treatment in ammonia water and mixing and stirring the liquid. Moreover, it can replace with ammonia water and the aqueous solution of water-soluble ammonium salt can also be used. Examples of water-soluble ammonium salts that can be used include ammonium sulfate, ammonium chloride, ammonium nitrate, and ammonium carbonate. In either case of using aqueous ammonia or an aqueous solution of a water-soluble ammonium salt, when the copper form of the object to be treated after completion of the oxidation treatment is metallic copper or cuprous oxide, air, It is preferable that an oxidizing agent such as potassium permanganate or hydrogen peroxide is mixed in the liquid to dissolve the object to be treated from the viewpoint of increasing the copper leaching rate.

  As another method, a method of suspending the object to be treated after the oxidation treatment in aqueous ammonia and adding an acid capable of forming an ammonium salt to the suspension to dissolve the object to be treated is adopted. be able to. By adopting this method, the leaching rate of copper can be further increased. As an acid capable of forming an ammonium salt, for example, a mineral acid such as sulfuric acid, hydrochloric acid, or nitric acid can be used. The higher the concentration of these acids, the more preferable because the equipment can be downsized. Even when this method is adopted, when the copper form of the object to be treated after the oxidation treatment is metallic copper or cuprous oxide, an oxidizing agent such as air potassium permanganate or hydrogen peroxide is contained in the liquid. Are preferably mixed to dissolve the object to be processed.

  Although there is no restriction | limiting in particular in the addition rate of the said acid, the leaching rate of copper becomes higher by the sequential addition rather than collective addition. When adding sequentially, it is preferable to add an acid equivalent to an ammonium ion in 1 to 6 hours.

  Instead of or in addition to the method of adding an acid capable of forming an ammonium salt, carbon dioxide gas may be blown into a liquid in which an object to be treated after the oxidation treatment is suspended in aqueous ammonia. By adopting this method, the copper leaching rate can be further increased. The amount of carbon dioxide blown is 0.01 to 5 liters / minute, particularly 0.1 to 1.5 liters / minute, with respect to 1 liter of the suspension in which the object to be treated is suspended in aqueous ammonia. From the viewpoint of further increasing the copper leaching rate. Even when this method is adopted, when the copper form of the object to be treated after the oxidation treatment is metallic copper or cuprous oxide, air, potassium permanganate, hydrogen peroxide are simultaneously injected with carbon dioxide gas. It is preferable to mix an oxidizing agent such as When air is used as the oxidant, the blowing rate is 0.1 to 10 liters / minute, particularly 0.5 to 5 liters / minute, with respect to 1 liter of the suspension in which the object to be treated is suspended in aqueous ammonia. It is preferable that

  In the case of using sulfuric acid, the object to be treated after the oxidation treatment and the dilute sulfuric acid aqueous solution may be mixed and stirred. The concentration of the dilute sulfuric acid aqueous solution is preferably 0.05 to 6 mol / liter, particularly 0.3 to 3 mol / liter from the viewpoint of efficient dissolution of copper oxide. The mixing and stirring of both may be performed at room temperature (20 to 25 ° C.) or may be performed under heating. In the case of heating, heating to about 40 to 90 ° C. is preferable from the viewpoint of promoting dissolution. When the concentration of the dilute sulfuric acid aqueous solution is within the above range, the mixing ratio between the dilute sulfuric acid aqueous solution and the object to be treated is diluted sulfuric acid with respect to 1 kg of the object to be treated after the oxidation treatment is finished. The aqueous solution is preferably 1 to 50 liters, particularly 5 to 20 liters. By dissolution using a dilute sulfuric acid aqueous solution, copper sulfate, which is a soluble compound, is produced in water.

  Among the ammonia-containing liquid and sulfuric acid described above, since sulfuric acid dissolves zinc and iron oxides simultaneously with copper oxide, zinc and iron ions are also present in the aqueous solution in addition to copper ions. It may be necessary to separate the metal species later. On the other hand, the ammonia-containing liquid selectively dissolves copper and cuprous oxide, but does not dissolve zinc, iron, or the like, so that separation of copper after dissolution is easy. Therefore, it is considered that it is advantageous in terms of the process to oxidize the object to be processed to produce copper and / or cuprous oxide and dissolve them with an ammonia-containing liquid. On the other hand, however, when using an ammonia-containing liquid, the loss due to volatilization of the ammonia-containing liquid and the need for device improvements to suppress the loss may be disadvantageous in terms of cost. There is. Considering these matters comprehensively, when the amount of impurities other than copper contained in the object to be treated is small, copper oxide is preferentially produced by vapor phase oxidation of the object to be treated, and this is treated with sulfuric acid. It is preferable to dissolve. On the other hand, when the amount of impurities other than copper contained in the object to be processed is large, metal copper and / or cuprous oxide is preferentially generated by vapor phase oxidation of the object to be processed, and this is an ammonia-containing liquid. It is preferable to dissolve.

In this way, an aqueous solution in which copper ionic species is dissolved is obtained. Copper is recovered from this aqueous solution according to a conventional method. Such methods are well known in the art. For example, a method in which scrap iron is put into a solution in which copper ions are dissolved and metal copper powder is recovered by a cementation method (“Nonferrous Metal Smelting”, Nippon Metallurgy, published on February 20, 1939, p170 : Cu ²⁺ Fe → Cu + Fe ²⁺ ) and SX−, which combines solvent extraction using an extractant specialized for copper extraction such as the extractant “LIX-84I” (manufactured by COGNIS, USA) and electrowinning Copper recovered by EW method ("Current status of solvent extraction technology, recovery of valuable materials from metal smelting and industrial waste", Yamamura Nishimura, "Resource treatment technology, VOL45, No1 (1998), p37-45") can do.

  According to the above method, valuable metals such as copper can be efficiently and easily recovered in a short time from copper-containing dross and mats that have been disposed of up to now. Therefore, the method of the present invention greatly contributes to resource saving and environmental load reduction. Furthermore, by adopting the method of the present invention in lead smelting, it becomes easy to dispose of waste even if a raw material ore containing many impurities such as copper, tin and other noble metal elements is used. There is an advantage that the range of choice of ore is expanded.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the above-described embodiment, either one of sulfuric acid or ammonia-containing liquid is allowed to act on the object to be processed after vapor phase oxidation. Instead, both sulfuric acid and ammonia-containing liquid are allowed to act sequentially. May be. Specifically, in the case where metal copper, cuprous oxide, and copper oxide are included in the same amount in the object to be processed after vapor phase oxidation, the ammonia-containing liquid is added after the sulfuric acid acts on the object to be processed. You may make it act, or you may make a sulfuric acid and ammonia containing liquid act in the reverse order.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” means “% by weight”.

[Example 1]
Copper-containing dross generated by lead smelting was used as the object to be treated. The XRD diffractogram of this copper-containing dross is as shown in FIG. 1 and was confirmed to contain PbS, SnO ₂ , Pb and Cu ₃ Sn. 100 kg of the copper-containing dross was supplied to a drum furnace and subjected to gas phase oxidation at 600 ° C. for 4 hours. Air was supplied to the drum furnace. The supply amount of air was adjusted by the opening degree of the valve attached to the air blowing pipe. In this example, the opening degree of the valve was set to 10% with respect to the full opening. An XRD diffractogram of the copper-containing dross after the oxidation treatment is shown in FIG. As is clear from the figure, it was confirmed that the copper-containing dross after the oxidation treatment contained metallic copper and cuprous oxide.

Next, 200 g of copper-containing dross after the oxidation treatment and ₂ liters of 1.75 mol / liter (NH ₄ ) ₂ CO ₃ aqueous solution were mixed to form a slurry, and air was blown into the slurry at a flow rate of 3 liters / minute. Stir for 3 hours. The temperature of the slurry was set to 65 ° C. Next, the slurry was subjected to solid-liquid separation, and the amount of copper contained in the filtrate was measured by ICP. The ratio of the amount of copper contained in the filtrate to the amount of copper contained in the copper-containing dross before the oxidation treatment (hereinafter referred to as “leaching rate”) was 85%.

[Example 2]
In Example 1, the opening degree of the drum furnace valve was set to 30% with respect to full opening. Otherwise, the copper-containing dross was vapor-phase oxidized in the same manner as in Example 1. As a result of XRD measurement, it was confirmed that the copper-containing dross after the oxidation treatment contained metallic copper and cuprous oxide. Thereafter, the copper in the copper-containing dross was recovered in the same manner as in Example 1. The copper leaching rate was 95%.

Example 3
In Example 1, the opening degree of the drum furnace valve was set to 60% with respect to full opening. Otherwise, the copper-containing dross was vapor-phase oxidized in the same manner as in Example 1. FIG. 3 shows an XRD diffractogram of the copper-containing dross after the oxidation treatment. As is clear from the figure, it was confirmed that the copper-containing dross after the oxidation treatment contained copper oxide.

  Next, 200 g of copper-containing dross after the oxidation treatment and 2 liters of a 1.5 mol / liter dilute sulfuric acid aqueous solution were mixed to form a slurry, and the slurry was stirred for 3 hours. The temperature of the slurry was set to 60 ° C. Next, the slurry was subjected to solid-liquid separation, and the amount of copper contained in the filtrate was measured in the same manner as in Example 1. As a result, the copper leaching rate was 95%.

[Comparative Example 1]
200 g of copper-containing dross itself not subjected to vapor phase oxidation treatment and ₂ liters of 1.75 mol / liter of (NH ₄ ) ₂ CO ₃ water are mixed to form a slurry, and air is supplied to this slurry at a flow rate of 3 liters / minute. The mixture was stirred for 3 hours. The temperature of the slurry was set to 65 ° C. Next, the slurry was subjected to solid-liquid separation, and the amount of copper contained in the filtrate was measured in the same manner as in Example 1. As a result, the leaching rate of copper was 30%.

[Comparative Example 2]
200 g of copper-containing dross itself not subjected to vapor phase oxidation treatment and 2 liter of 1.5 mol / l dilute sulfuric acid aqueous solution were mixed to form a slurry, and this slurry was stirred for 3 hours. The temperature of the slurry was set to 60 ° C. Next, the slurry was subjected to solid-liquid separation, and the amount of copper contained in the filtrate was measured in the same manner as in Example 1. As a result, the copper leaching rate was 50%.

Example 4
The copper-containing dross similar to Example 1 was used as a to-be-processed object. This copper-containing dross was vapor-phase oxidized with a rotary kiln. The amount of copper-containing dross supplied to the rotary kiln was 100 kg / h. The amount of air supplied to the rotary kiln was adjusted by the opening degree of a valve attached to the air blowing pipe. In this example, the opening of the valve was set to 30% with respect to the full opening. The time and temperature of the oxidation treatment were as shown in FIG. As a result of XRD measurement, it was confirmed that the copper-containing dross after the oxidation treatment contained metallic copper and cuprous oxide. Thereafter, in the same manner as in Example 1, copper in the copper-containing dross was recovered using a (NH ₄ ) ₂ CO ₃ aqueous solution. The leaching rate of copper is shown in FIG.

Example 5
200 g of copper-containing dross subjected to the same oxidation treatment as in Example 1 and ₂ liters of 1.75 mol / liter (NH ₄ ) ₂ CO ₃ aqueous solution were mixed to form a slurry. The slurry was stirred for 3 hours while blowing air of a flow rate of 3 liters / minute and CO ₂ gas of 0.3 liters / minute. The temperature of the slurry was set to 65 ° C. Next, the slurry was subjected to solid-liquid separation, and the leaching rate of copper contained in the filtrate was measured in the same manner as in Example 1. As a result, the copper leaching rate was 90%.

  As is apparent from the results of the above examples, it can be seen that copper can be easily recovered at a high rate by applying the method of the present invention to copper-containing dross generated by lead smelting. On the other hand, it is understood that copper cannot be efficiently recovered even if an ammonia-containing liquid or sulfuric acid is allowed to act on copper-containing dross that has not been subjected to any treatment.

Claims (8)

The object to be treated containing oxygen-free copper compound slightly soluble in gas phase oxidation, metallic copper or the acid Motohi containing copper compound to produce a cuprous oxide, and then to said processed material after the vapor phase oxidation process by applying an aqueous solution containing ammonia, copper recovery method of copper from copper-containing article to be treated, characterized in that recovered without the form of a soluble salt.    The copper recovery method according to claim 1, wherein the object to be treated is copper-containing dross or mat produced by lead smelting, lead ore containing copper, or lead sulfide containing copper.    The copper recovery method according to claim 1 or 2, wherein the oxygen-free copper compound is a compound of Cu and at least one element selected from Sn, Sb, S, and Se.    The copper recovery method according to claim 3, wherein the oxygen-free copper compound is a compound containing Cu—Sb—Sn.    The object to be treated is vapor-phase oxidized to produce copper or cuprous oxide, and then the object to be treated after the gas-phase oxidation treatment is reacted with an aqueous solution of ammonia water or a water-soluble ammonium salt and an oxidizing agent to produce copper. The copper recovery method according to any one of claims 1 to 4, wherein an ammine complex is formed.    The object to be treated is vapor-phase oxidized to produce copper or cuprous oxide, and then the object to be treated after the gas-phase oxidation treatment is suspended in aqueous ammonia, and an ammonium salt is formed in the resulting suspension. The copper collection | recovery method in any one of Claim 1 thru | or 4 which makes the acid which can be acted produce | generate a copper ammine complex.    The object to be treated is vapor-phase oxidized to produce copper or cuprous oxide, and then the object to be treated after the gas-phase oxidation treatment with ammonia water is suspended. The copper recovery method according to claim 5, wherein a copper ammine complex is produced by reacting carbon dioxide or an acid capable of forming an ammonium salt. The object to be treated is vapor-phase oxidized to produce copper or cuprous oxide, and then the object to be treated after the gas-phase oxidation treatment with ammonia water is suspended, and air and carbon dioxide gas are suspended in the obtained suspension. The copper recovery method according to claim 7, wherein a copper ammine complex is produced by acting.

Images