JPS628489B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for continuous smelting of sulfide metal ores, which allows continuous smelting of sulfide metal ores to be carried out stably even when the sulfide to metal ratio in the sulfide metal ores decreases. The present applicant has already disclosed a continuous smelting method for metal sulfide ore in Japanese Patent Application Laid-Open No. 15703/1983. This disclosed continuous smelting method (hereinafter referred to as the conventional method)
is a melted raw material whose main components are metal sulfide ore and a solvent, mixed with fuel and air in proportions that suit preset reaction conditions, into a solution that is a reaction product of a smelting furnace. A predetermined amount of supply per unit time is directly and continuously charged and melted to produce 〓 and 〓, and at that time, the smelting furnace 〓 produced in the smelting furnace is solidified and pulverized to the above-mentioned smelting furnace. The total amount of products in the smelting process and the smelting process of the first step in which most of the target metal contained in the smelting furnace is absorbed into the smelting furnace by substantially continuous blowing into the solution. Air, solvent, and coolant are appropriately mixed with the separation process of the second step, which is sent to the separation tank and separated into 〓 and 〓, and the 〓 from the separation process is continuously charged into the smelting furnace. The third step is a smelting step in which the target metal and the above-mentioned smelting furnace are continuously produced by the oxidation reaction of iron and sulfur. This makes it possible to recover target metals in high yields with high thermal efficiency. However, due to the recent ore situation, that is, sulfide metal ores, such as copper ores, there is a tendency for S/Cu (weight %) to decrease and copper grade to increase due to changes in ore deposits and the lack of development in ore beneficiation technology. For example, one type of major imported copper ore is traditionally Cu28.5
%, S33.4%, Fe28.6% is Cu31.8
%, S27.2% Fe25.8%. In addition, this continuous smelting method for metal sulfide ores has superior adaptability to changes in ore conditions compared to other smelting methods, but in the case of extremely high-grade ore processing, If Cu is significantly reduced, the ratio of air or oxygen-enriched air to the raw ore will be lower than in normal grade ore processing in order to maintain the target grade. A problem is occurring. (1) The heat of oxidation reaction of iron and sulfur in the ore decreases. (2) Stirring of the solution is weakened, reducing reaction efficiency. (3) Due to (2), the solution temperature decreases, the viscosity of the solution increases, and the fluidity deteriorates. (4) Slag loss increases due to the slowdown of the dissolution reaction due to a decrease in the stirring power of the solution and the subsequent increase in viscosity due to the decrease in temperature of the solution. (5) To compensate for the above drop in solution temperature, the amount of burner firing increases. (6) As the amount of burner firing increases, the burner frame causes further erosion of the furnace wall, shortening the life of the furnace. (7) The exhaust gas temperature rises, causing problems with the exhaust gas system. (8) When the lance air flow rate decreases, the lance cooling effect decreases and the lance wears out due to the increase in the furnace atmosphere temperature due to (5). The phenomena described in ~(7) occur even when the airflow rate is normal. As described above, conventional methods cannot be effectively applied to the treatment of extremely high-grade metal sulfide ores, and it has been difficult to stably and continuously smelt metal sulfide ores. FIG. 5 is a graph showing the relationship between the copper grade in the copper concentrate and the lower limit of the sulfur grade in order to set the grade to 65% when copper concentrate is used as the metal sulfide ore. In this case, the 〓 produced in the above smelting furnace is
It is an intermediate product consisting of Cu ₂ S and FeS, and therefore the amount of sulfur involved in the grade is necessary, but the amount of sulfur involved in the heat of oxidation reaction is due to the amount of sulfur involved in the heat of oxidation reaction, which is due to the carbon and hydrogen in fluid solid fuels, such as powdered coal. It can be replaced with . The standard target value for grain quality is 65%, so the sulfur content in the grain is 22%. Currently, the copper grade of 〓 is 65%, and the copper grade of copper concentrate is 30%.
Assuming that, as shown in Figure 5, it is possible to operate with a sulfur grade of 10.15. For example, = quality 5%
When the copper grade in the copper concentrate is 28 to 32%, the lower limit of the sulfur grade in the copper concentrate is in the range shown in FIG. If the sulfur grade is lower than that, the grade must be increased. The present invention solves the above-mentioned drawbacks of the conventional method, and produces a sulfide metal ore that enables stable continuous smelting of the sulfide metal ore even when the sulfur to metal ratio in the sulfide metal ore decreases. It provides a continuous smelting method, and its gist is to mix air and fluid solid fuel appropriately with a raw material consisting of a mixture of sulfide metal ore and a solvent, and to continuously load this into a smelting furnace. In this case, the smelting furnace 〓 from the smelting furnace is solidified and crushed and continuously charged into the smelting furnace to be contained in the smelting furnace. A smelting process in which most of the target metal is absorbed into the above-mentioned metal, a separation process in which the product of the smelting process is transferred to a metal separation tank and separated into two, and a solvent is added to the liquid from the separation process. In the continuous smelting method for sulfide metal ore, which comprises a smelting process in which air is appropriately blended and continuously charged into the smelting furnace to produce the target metal and the smelting furnace, In order to ensure the required stirring of the solution to promote the melting of the raw material charged into the smelting furnace in the smelting process, the minimum air flow rate is set according to the operating conditions, and the raw material is charged into the smelting furnace. In addition to the oxidizing air flow rate calculated to maintain the target grade based on the grade of sulfide metal ore produced in the smelting furnace and the grade of 〓 and 〓 produced in the smelting furnace, the minimum The supplementary air necessary to maintain the air flow rate and the corresponding fluid solid fuel are blown directly into the solution through a lance, and the iron, sulfur, etc. in the solution in the smelting furnace of the smelting process are oxidized. The grade and amount of oxygen in the air charged to the smelting furnace to ensure the required agitation of the solution necessary for effective oxidation of the components and more rapid heat transfer within the solution. The ingredients and amount of 〓 from the above separation tank,
In addition to the oxidizing air flow rate calculated based on the composition and amount of the refrigerant, the amount of replenishment air necessary to maintain the minimum air flow rate corresponding to the grade and the corresponding fluid solid fuel are directly delivered via the lance. A continuous smelting method for sulfide metal ore, characterized by blowing into the solution. Next, the present invention will be explained with reference to the drawings. The fluid solid fuel used in the present invention may be any solid fuel in powder form, and includes coal, charcoal, coke, sawdust, solid carbon, sulfur, plastic, rubber, and the like. Below, copper concentrate is used as sulfide metal ore,
We will also discuss the use of powdered coal as a fluid solid fuel. Fig. 1 is a system flow diagram in the smelting process of an embodiment of the present invention, Fig. 2 is a schematic diagram of the copper concentrate, solvent, and powdered coal charging equipment in the smelting process of Fig. 1;
3 is a sectional view of the smelting furnace in the smelting process shown in FIG. In the refining process, copper concentrate feed amount is 25T/hr, production grade is 65%, 80% oxygen is 2500N
FIG ^{. 3} is a graph showing the relationship between S/Cu in copper concentrate, lance wind speed, and amount of heavy oil when m 3 /hr and five 3-inch lances are used. First, the smelting process of the present invention will be described. In Figure 1, the grade of copper concentrate charged into the smelting furnace in the smelting process, the grade of the solvent, and the amount produced in the smelting furnace
Based on the grades of and 〓, the amount of oxygen required for reaction and the amount of solvent required per ton of copper concentrate are calculated, and after collecting the physical quantity data, the amount of air flow and temperature control are calculated to determine the amount of air flow and burner heavy oil. Ru. In order to maintain the quality of 〓 produced in the smelting furnace at the target 〓 grade, the oxidation This system directly charges into the solution the amount of replenishing air necessary to maintain the minimum speed of air flow and the amount of powdered coal corresponding to the air flow rate in accordance with the degree of increase in the grade of the metal sulfide ore. The above preset minimum air flow rate is the amount of air that can sufficiently stir the solution in the smelting furnace and sufficiently promote the melting of the raw materials charged into the smelting furnace. It is set according to the operating conditions. Now, due to the above-mentioned ore circumstances, the S/Cu in copper concentrate is decreasing, and when processing high copper grade copper concentrate, due to the decrease in S/Cu, the above calculated air flow rate, that is, the air flow rate for oxidation, is lowered. If the air flow rate is lower than the preset minimum air flow rate, in addition to the above-mentioned oxidation air flow rate, supplementary air necessary to maintain the minimum air flow rate at all times as described above will be added in accordance with the degree of increase in the grade of the metal sulfide ore. The appropriate amount of powdered coal is charged. Quantity data of the charged pulverized coal is collected as described above, thermal calculation is performed, and the amount of burner heavy oil is correspondingly reduced. In this case, the relationship between the calorific value of sulfur in heavy oil, powdered coal, and copper concentrate, effective calorific value, and amount of combustion air is as shown in the following table.

[Table] The effective calorific value in the table above is calculated from the calorific value of the fuel combusted in the furnace using the theoretical amount of air.
This is the amount of heat that effectively works in the furnace after subtracting the amount of heat carried away by the exhaust gas when it exits at ℃. Figure 2 shows the pulverized coal charging equipment. In the figure, 1
2 is a belt feeder, 3 is a weyer, 4 is a chute, and 5 is a transport chain conveyor. The amount of pulverized coal calculated as above is cut out from the hopper 1 by the belt feeder 2, weighed by the weir 3, then enters the transport chain conveyor 5 through the chute 4, and is transported to the top charging equipment of the smelting furnace. . The same applies to copper concentrate and solvent. FIG. 3 is a sectional view of the smelting furnace. In the figure,
6 is a lance, 7 is a burner, 8 is a solution outflow hole, 9 is a wharf, and 10 is a solution. In the smelting furnace, a mixture of powdered coal and air in a proportion appropriate to the planned reaction conditions is added to the raw material whose main component is a solvent such as ore (copper concentrate) and silicate, and the reaction products in the furnace are fed at a predetermined feeding rate. directly and continuously into the solution 10. At that time, as shown in FIGS. 2 and 3, the powdered coal may be directly fed into the solution 10 together with the raw material using the same lance 6 as the raw material, or it may be directly blown into the solution 10 using a lance exclusively for powdered coal. You may. The pulverized coal supplied into the solution 10 is normally completely combusted in the furnace, but if excessively supplied, unburned pulverized coal may float on the solution 10 and flow out from the solution outlet hole 8. Therefore, by attaching the wharf 3 to the melt outlet of the furnace, it is possible to prevent the unburned coal from flowing out of the furnace, and the unburned coal will eventually burn out inside the furnace. Figure 6 shows copper concentrate feed amount 25T/hr, production = grade 65
%, 80% oxygen at 2500 Nm ³ /hr, and five 3-inch lances are used. It is a graph showing the relationship between S/Cu in copper concentrate, lance wind speed, and amount of heavy oil. The lance wind speed is calculated using the following formula. Lance air speed = (air volume + oxygen volume) / (3600 ^seconds x 0.005 ^m2 ) In order to keep the amount of copper ore feed constant, if the lance wind speed decreases to 2700Nm ³ /hr at the calculated time, that is, if the lance wind speed decreases from 180m/sec to 150m/sec, the solution oxidation reaction heat must be The reduction must be supplemented with external heating. At this time, if external heat supplementation is performed from a normal burner, for example, the rate of transfer of heat generated by the burner to the solution decreases due to the decrease in the stirring phenomenon of the solution that occurs as the lance wind speed decreases. However, the temperature of the solution decreased and the melting of the raw material charge was not effectively promoted. When the S/Cu in the copper ore decreases, if the amount of air blowing to obtain the prescribed solution stirring is constantly supplied, the grade will continue to rise. Due to reasons such as suspension of ore supply in cases of In Figure 6, for example, the minimum lance wind speed is 150
m/sec, that is, the minimum air flow rate of 11000 Nm ³ /hr, if S/Cu in the copper ore is 0.9, the air flow rate will be insufficient by 3100 Nm ³ /hr. From the table above, the amount of powdered coal corresponding to the amount of supplementary air required to maintain the minimum air flow rate is 408 kg. Powdered coal amount 408
The calorific value per kg/hr is 1,346,000 Kcal, and the equivalent amount of heavy oil can be saved by 369 kg. This is a model calculation value, but in actual operation, the grade changes and the S/Cu of copper ore varies, so the amount of oxygen required per ton of ore increases or decreases, and the minimum air flow rate set accordingly Based on this, the amount of pulverized coal charged will also be increased or decreased. Further, the set minimum air flow rate can be set arbitrarily, and by increasing the set value, it becomes possible to use pulverized coal arbitrarily within a range that allows the lance air flow rate. As described above, the present invention blows powdered coal directly into the solution, which improves heat transfer to the solution compared to conventional burner heating methods, and improves melting ability because the solution is sufficiently stirred. Since the fluidity of the solution improves, the product can flow out of the furnace smoothly, and at the same time, the stirring ensures sufficient contact between the solution and the solution, and the suspended particles easily become coarse and settle. However, the copper loss in the middle will be reduced. Also,
Since the transfer of combustion heat to the solution is improved, the temperature difference between the ambient temperature in the furnace gas zone and the solution can be reduced, and the amount of burner firing is reduced.As a result, the life of the furnace wall, which is eroded by the burner flame, is shortened. significantly extended. Furthermore, the temperature of the exhaust gas can be lowered to almost the same temperature as the solution temperature.
This is extremely advantageous in terms of after-treatment of exhaust gas. The above-mentioned lance injection of powdered coal can be carried out without any changes to conventional heavy oil burner equipment, and it is possible to reduce the amount of heavy oil used.
This partial conversion to pulverized coal as a fuel source is extremely significant considering the current global oil situation. Next, the smelting process of the present invention will be described. In the smelting process as well, powdered coal lance injection into the copper making furnace can be carried out in the same manner as in the case of the above-mentioned smelting furnace. FIG. 4 is a sectional view of a copper making furnace corresponding to the smelting furnace of FIG. 3. In the figure, 11 is a lance, 12 is an inlet from the separation process, 13 is a burner, 14 is a blister copper outlet, 15 is a copper furnace outlet, and 16 is a solution. That is, the solution 16 is necessary for effective oxidation of oxidized components such as iron and sulfur in the solution 16 in the copper furnace in the smelting process and for more rapid heat transfer within the solution 16.
The minimum amount of air flow to ensure the required agitation of If the oxidizing air flow rate calculated based on the composition and amount of the refrigerant is lower than the above-mentioned set low air flow rate due to a decrease in the charging amount or excessive oxidation in the copper making furnace, etc. In addition to the oxidizing air flow rate, supplementary air volume necessary to maintain the minimum air flow rate and powdered coal commensurate with the supplementary air volume are blown directly into the solution 16 through the lance 11. In this case, the excess heat generated is used for charging and melting a coolant such as scrap of the target metal, making it possible to increase the overall ore processing capacity. Further, controlled charging of pulverized coal can be performed to perform coolant charging melting of target metal scrap or the like to increase overall ore processing capacity. Although the present invention has been described above in the case where the sulfide metal ore is copper sulfide, it goes without saying that the present invention is also applicable to sulfide ores such as nickel and cobalt. As described above, the present invention enables effective stirring of the in-furnace solution in the smelting furnace and the smelting furnace even when the grade of sulfide metal ore increases.
Continuous production of sulfide metal ore that enables the stable, large-scale, and economical production of target metals by controlling the direct blowing of a fluid solid fuel into a solution through a top-blown lance. It provides a method of alchemy, and its industrial value is extremely high. EXAMPLES Next, the present invention will be specifically explained using Examples, but the present invention is not limited to the following Examples unless the gist of the invention is exceeded. Example: 29.73% copper per hour in the smelting furnace of the smelting process,
24.4T copper concentrate consisting of 29.63% sulfur, 24.97% iron, and 6.58% silicic acid, 3.4T silica sand, and 0.1T lime at a gauge pressure of 2
Air was blown at a minimum blowing rate ^of 11,700 Nm ³ /hr and oxygen gas was blown through a lance directly into the solution ^, which was a reaction product, in the smelting furnace. These copper concentrate, silica sand, and lime are each dried to a particle size of 3 m/m or less and a moisture content of 1% or less, and the lance is a 3 inch pipe (inner diameter 80.1 m/m).
m) Using 5 lances, the flow velocity inside the lance is 155m/sec.
It was hot. In this way, the oxidizing air flow rate calculated to maintain the target grade based on the grade of sulfide metal ore charged into the smelting furnace and the grades of If the airflow rate is lower than the airflow rate, maintain the minimum airflow rate in addition to the oxidation airflow rate.
For 11,700 Nm ³ /hr, the amount of supplementary air necessary to maintain the minimum air flow rate and the corresponding amount of powdered coal of 873 kg/hr were also blown directly into the solution via a lance. As a result, burner heavy oil will be reduced from 1400/hr to 931/hr.
hr, and the solution temperature increased from 1188℃ to 1213℃. The entire amount of 〓 and 〓 produced in the smelting furnace was transferred to a separation tank for the next separation step and separated into 〓 and 〓. Next, 11.5T and 0.7T of lime, each consisting of 64.9% copper, 21.83% sulfur, and 9.91% iron, are added to the copper furnace in the smelting process from the separation tank every hour at 8240N at a gauge pressure of 2Kg/ ^cm2.
It was blown directly into the solution, which is a reaction product, in a copper making furnace through four 3-inch lances together with air at m ³ /hr and 80% oxygen gas at 1000 Nm ³ /hr. The heat balance inside the copper making furnace is in equilibrium, the amount of burner heavy oil is zero, the solution temperature is 1230℃, and the copper making furnace is in equilibrium.
The copper content inside was 16%. When the air flow rate was set to the minimum air flow setting value of 10,000Nm ³ /hr, 230Kg/hr of powdered coal was blown through the lance to compensate for the excess air, and 4,100Kg/hr of anode residue was charged to compensate for the excess heat. . The solution temperature was 1230°C and the copper content in the copper making furnace was 15%.

[Brief explanation of the drawing]

Fig. 1 is a system flow diagram in the smelting process of an embodiment of the present invention, Fig. 2 is a schematic diagram of the copper concentrate, solvent, and powdered coal charging equipment in the smelting process of Fig. 1;
Figure 3 is a cross-sectional view of the smelting furnace in the smelting process shown in Figure 1, Figure 4 is a cross-sectional view of the copper making furnace in the smelting process of the embodiment shown in Figure 1, and Figure 5 shows copper as sulfide metal ore. When using concentrate, Graph diagram showing the relationship between the copper grade and the lower limit of sulfur grade in copper concentrate to make the grade 65%, No. 6
The figure shows the amount of copper concentrate fed in the smelting process in Figure 1.
25T/hr, production = grade 65%, 80% oxygen 2500Nm ³ /
hr, S/ in copper concentrate when using five 3-inch lances
It is a graph diagram showing the relationship between Cu, lance wind speed, and amount of heavy oil. In Figures 2, 3, and 4, 1...pulverized coal hopper, 2...belt feeder, 3
...Wayer, 4...Chute, 5...Transportation chain conveyor, 6,11...Lance, 7,13...
... Burner, 8 ... Solution outflow hole, 9 ... Wharf, 1
0,16...solution, 12...=inlet, 14...blister copper outlet, 15...coppermaking furnace=outlet.

Claims (1)

[Claims] 1. A raw material consisting of a mixture of metal sulfide ore and a solvent is appropriately mixed with air and a fluid solid fuel, and this is continuously charged into a smelting furnace and melted to produce 〓 and 〓. A smelting process in which the smelting furnace from the furnace is solidified and crushed and continuously charged into the smelting furnace to absorb most of the target metal contained in the smelting furnace into the smelting furnace. A separation step in which the entire amount of the product of the smelting process is transferred to a separation tank and separated into a In a continuous smelting method for sulfide metal ore, which comprises a smelting process in which the raw material is charged into the smelting furnace to produce the target metal and the above-mentioned smelting furnace, the above-mentioned raw material charged to the smelting furnace in the smelting process is melted in advance. The minimum amount of air blowing to ensure the required stirring of the solution to promote acceleration is set according to the operating conditions, and the grade of metal sulfide ore charged to the smelting furnace and the amount produced in the smelting furnace are determined. In addition to the oxidizing air flow rate calculated to maintain the target grade based on the grade of and, the supplementary air amount necessary to maintain the minimum air flow rate and the fluid solid fuel corresponding to the grade of the metal sulfide ore. Blow directly into the solution through a lance, and effectively oxidize components to be oxidized such as iron and sulfur in the solution in the smelting furnace of the smelting process, and more rapidly transfer heat within the solution. The minimum amount of air blowing to ensure the required agitation of the solution is set according to the grade charged into the smelting furnace and the amount of oxygen in the air, and the components of 〓 from the separation tank are In addition to the oxidizing air flow rate calculated based on the composition and amount of the refrigerant, the replenishment air amount necessary to maintain the minimum air flow rate and the corresponding fluid solid fuel according to the grade are added to the lance. A method for continuous smelting of metal sulfide, characterized in that the metal sulfide is blown directly into the solution through the sulfide.