Method for recovering cu from zinc sulfate solution

Abstract

A method for recovering Cu from a zinc sulfate solution, according to one embodiment of the present invention, is a method for recovering Cu from a zinc sulfate solution produced from a leaching process in which zinc ore is dissolved in sulfuric acid, comprising: a neutral leaching step of dissolving the zinc ore; a weak acid leaching step of producing a zinc sulfate solution by dissolving, in sulfuric acid, the solution resulting from the neutral leaching step in which the zinc ore is dissolved; a copper removal step of removing, in the form of copper cement, copper dissolved in the zinc sulfate solution; a conditioning step of reducing the solution resulting and discharged from the copper removal step; a repulping step of repulping a conditioning cake, which is a solid discharged from the conditioning step, with a zinc solution; and a solution purification leaching step of dissolving, in sulfuric acid, the solution resulting and discharged from the repulping step, thereby dissolving copper contained in the solution resulting from the repulping step, wherein zinc calcine is injected into the solution resulting and discharged from the solution purification leaching step, and then the solution resulting from the solution purification leaching step is injected back into the weak acid leaching step.

Description

Method for recovering copper from zinc sulfate solution

[0001] The present invention relates to a method for recovering copper contained in a zinc sulfate solution.

[0002] The zinc refining process generally consists of a roasting process to oxidize the concentrate (ZnS) in the form of sulfide ore, a leaching process to dissolve the slag (ZnO) produced in the roasting process in sulfuric acid, and a multi-stage refining process to purify impurities. The resulting pure zinc sulfate solution is then electrolyzed to precipitate zinc at the cathode. In the leaching process, various metal components such as iron (Fe), copper (Cu), nickel (Ni), cobalt (Co), and cadmium (Cd) contained in the zinc concentrate are leached together. Among the leached metal components, copper in particular is discharged in the form of copper cement through the decoppering process, and the discharged copper cement can be recovered in the form of pure copper through the copper refining process.

[0003] In the past, copper was recovered by dry refining the byproducts generated in the zinc refining process. However, in the case of dry refining, the copper recovery rate is limited to about 50% to 70%, and the copper grade in the slag generated in the dry refining method is 0.3% to 0.5%, so the recovery rate of the valuable metal is low.

[0004] In addition, the conventional dry smelting method has the disadvantage of requiring a lot of energy due to its nature and thus requires the use of large amounts of fossil fuels.

[0005] In recovering copper contained in a zinc sulfate solution, a method is provided that can recover more than 90% of the dissolved copper among the raw materials of zinc wet refining by linking the byproduct generated in the solidification process to the de-coppering process in the existing zinc wet refining process.

[0006] In addition, in recovering copper contained in a zinc sulfate solution, a method is provided that can minimize refining costs by linking it to a de-coppering process in an existing zinc wet refining process without a separate refining process for copper recovery.

[0007] In addition, in recovering copper contained in a zinc sulfate solution, a method is provided that can increase the recovery rate of zinc in a zinc wet refining process by additionally recovering zinc contained in the by-products generated in the solid solution process by linking them to an existing zinc wet refining process.

[0008] A method for recovering copper from a zinc sulfate solution produced from a leaching process of dissolving zinc ore in sulfuric acid according to one embodiment of the present invention comprises: a neutral leaching process of dissolving the zinc ore, a weak acid leaching process of dissolving the neutral leaching process liquid in which the zinc ore is dissolved with sulfuric acid to produce a zinc sulfate solution, a decoupling process of removing copper dissolved in the zinc sulfate solution in the form of copper cement, a conditioning process of reducing the decoupling process liquid discharged from the decoupling process, a repulping process of repulping a conditioning cake, which is a solid discharged from the conditioning process, with a zinc solution, and a liquid leaching process of dissolving the repulping process liquid discharged from the repulping process with sulfuric acid to dissolve copper contained in the repulping process liquid, wherein the liquid leaching process liquid discharged from the liquid leaching process is neutralized by adding zinc quenching and then returned to the weak acid leaching process.

[0009] The zinc sulfate solution reintroduced into the above weak acid leaching process can be reintroduced into the above de-copperization process.

[0010] The above conditioning process reduces the post-treatment liquid from the above-mentioned de-ionization process to produce a post-treatment liquid, and the post-treatment liquid from the above-mentioned conditioning process is treated in a thickener and a filter, and the discharged solution is used as the precipitation process input liquid to be input to the precipitation process, and the solids can be discharged as the conditioning cake.

[0011] The above iron precipitation process input liquid can be input into an iron precipitation process that recovers iron oxide through a pressure oxidation process.

[0012] The above iron precipitation process generates a post-iron precipitation process liquid through the above pressure oxidation process, treats the post-iron precipitation process liquid in a thickener and a filter, and transfers the discharged solution to the neutral leaching process, and the solids can be discharged as iron oxide.

[0013] The above repulping process can be performed at a process temperature of 60°C to 80°C and a pH of 2.5 to 3.0.

[0014] In the above repulping process, the concentration of the conditioning cake in the zinc solution may be 100 g / L to 200 g / L.

[0015] The concentration of sulfuric acid in the liquid after the above-mentioned semen extraction process may be 25 g / L to 50 g / L.

[0016] In the above-mentioned semen leaching process, more than 85% of the copper contained in the conditioning cake can be dissolved.

[0017] In the above-mentioned semen leaching process, 92% or more of iron and 98% or more of zinc contained in the conditioning cake can be dissolved.

[0018] The above-mentioned semen extraction process is performed for 2 to 3 hours, the dissolution temperature may be 60°C to 80°C, and the process pressure may be 1 to 2 atm.

[0019] The pH of the above weak acid leaching process may be 2.5 to 3.0.

[0020] The process time of the above weak acid leaching process may be 3 to 4 hours.

[0021] According to the present invention, by re-introducing by-products generated in the fixed-rate process into the existing zinc wet smelting process multiple times, the recovery rate of dissolved copper among the raw materials of zinc wet smelting can be maximized.

[0022] In addition, the cost required for copper smelting can be minimized by linking it with the existing zinc smelting process without going through a separate smelting process for copper recovery.

[0023] In addition, the recovery rate of zinc can be increased by reintroducing zinc contained in the byproducts generated in the semen process into the zinc refining process.

[0024] Figure 1 is a process flow diagram for recovering copper according to one embodiment of the present invention.

[0025] FIG. 2 is a process flow diagram specifically illustrating a repulping process, a liquid leaching process, and a neutralization process in a method for recovering copper from a zinc sulfate solution according to one embodiment of the present invention.

[0026] In a typical zinc smelting process, zinc raw materials are leached into sulfuric acid, and iron (Fe), copper (Cu), etc. are also leached into the sulfuric acid. The copper contained in the leaching solution is separated into solid and liquid, and then a strong reducing agent such as zinc dust is added to reduce and precipitate the copper (Cu) dissolved in the form of copper sulfate (CuSO4) into a precipitate called copper cement (Cu Cement) and remove it. In addition, a significant amount of iron is dissolved in the zinc sulfate solution, and it is sent to the iron removal process (Fe Precipitation) to remove the iron.

[0027] The present invention is an invention that aims to maximize the recovery rate of dissolved copper among raw materials for zinc wet smelting, and to recover more than 90% of copper ions contained in a leachate generated in a zinc smelting process.

[0028] Figure 1 is a process flow diagram for recovering copper according to one embodiment of the present invention.

[0029] Referring to Figure 1, in the zinc refining process, zinc-containing raw materials, such as zinc concentrate, zinc ore, or zinc ferrite, are leached with sulfuric acid under atmospheric pressure to produce a zinc sulfate solution. The sulfuric acid remaining in the leaching process is neutralized with quenching to primarily remove impurities (neutral leaching process (S1)). Copper components leached together with the raw material during the leaching process are not precipitated during the neutralization process and therefore remain in the process solution after neutralization.

[0030] The solution that has gone through a neutralization process after dissolving the raw material containing zinc is a post-neutral leaching process liquid, and the post-neutral leaching process liquid is dissolved again with sulfuric acid to produce a zinc sulfate solution (weak acid leaching process (S2)). The pH of the weak acid leaching process (S2) can be about 2.5 to 3.0, and the weak acid leaching process can be performed in a thickener. The retention time of the zinc sulfate solution in the weak acid leaching process (S2) is about 3 to 4 hours, and the process temperature of the weak acid leaching process can be performed at about 65°C.

[0031] A large amount of copper is dissolved in the zinc sulfate solution discharged from the weak acid leaching process (S2). By adding a strong reducing agent such as zinc powder to the zinc sulfate solution, the copper (Cu) dissolved in the form of copper sulfate (CuSO4) can be reduced and precipitated into copper cement (Cu Cement), which is a metallic copper powder, and removed (decopper removal process (S3)). Copper cement can be recovered in the form of pure copper through a copper smelting process.

[0032] The de-coating process effluent discharged from the de-coating process (S3) is fed into the conditioning process (S4). In the conditioning process (S4), the de-coating process effluent is fed into a conditioning tank, passes through a thickener, and the solids are discharged as a conditioning cake through a filter. The effluent that has gone through the conditioning process (S4) is fed as an iron precipitation process input to the iron precipitation process (S5) that recovers iron oxide through a pressure oxidation process. In the iron precipitation process (S5), the iron precipitation process input is fed into the iron precipitation tank, passes through a thickener and a filter, and the solids are discharged in the form of iron oxide. The solution is transferred to the neutral leaching process (S1) as an iron precipitation process effluent. The post-iron precipitation process slurry can be considered a pure zinc sulfate solution with a high zinc content, as copper is discharged in the form of copper cement and iron in the form of iron oxide during the de-copperization process (S3) and the iron precipitation process (S5). The zinc sulfate solution is then transferred to a process where it is electrolyzed to precipitate zinc at the cathode.

[0033] The conditioning cake discharged from the conditioning process (S4) still contains valuable metals such as copper, iron, and zinc. In order to recover the metals contained in the conditioning cake, it is necessary to melt the copper, iron, and zinc contained in the conditioning cake and transfer them to a de-copperization process, an iron precipitation process, an electrolysis process, etc.

[0034] To this end, the conditioning cake discharged from the conditioning process (S4) is repulped with a zinc solution at a temperature of about 60°C to 80°C for about 1.5 hours (repulping process (S6)). The repulping process (S6) can be performed at a pH range of about 2.5 to 3.0, and the concentration of the conditioning cake in the zinc solution in the repulping process (S6) can be about 100 g / L to 200 g / L.

[0035] The repulping process slurry discharged from the repulping process (S6) is dissolved with sulfuric acid, thereby dissolving most of the copper contained in the repulping process slurry (liquid leaching process (S7)). The concentration of sulfuric acid introduced here can be about 25 g / L to 50 g / L. The liquid leaching process (S7) is performed for about 2 to 3 hours, at a dissolution temperature of about 60°C to 80°C, and at a process pressure of about 1 to 2 atm. Through the liquid leaching process (S7) as described above, about 85% or more of the copper contained in the conditioning cake can be dissolved. In addition, in the liquid leaching process (S7), not only copper contained in the conditioning cake, but also iron, zinc, etc. are leached together. Specifically, in the liquid leaching process (S7), about 92% or more of iron contained in the conditioning cake is dissolved, and about 98% or more of zinc is dissolved.

[0036] The liquid after the semen leaching process discharged from the semen leaching process (S7) is fed back into the weak acid leaching process (S2) after going through a process of neutralizing it by adding zinc quenching (neutralization process (S8)). The liquid after the semen leaching process discharged from the neutral leaching process (S1) is dissolved in sulfuric acid together with the liquid after the neutral leaching process discharged from the neutral leaching process (S1) and fed back into the de-copperization process (S3) in the form of a zinc sulfate solution.

[0037] By dissolving a large amount of copper, iron, zinc, etc. contained in the conditioning cake, which is a byproduct of the conditioning process (S4), through the above-mentioned liquid leaching process (S7), and then feeding it back into the weak acid leaching process (S2) of the zinc refining process, valuable metals, especially copper, that would otherwise be discarded as a conditioning cake can be recovered. Therefore, the recovery rate of dissolved copper among the raw materials of zinc hydrorefining can be maximized, and by also feeding the zinc contained in the byproduct back into the zinc refining process, the recovery rate of zinc can also be increased. In addition, by linking it with the existing zinc refining process instead of going through a separate copper refining process for copper recovery, the cost required for copper refining can also be minimized.

[0038] FIG. 2 is a process flow diagram specifically illustrating a repulping process (S6), a liquid leaching process (S7), and a neutralization process (S8) in a method for recovering copper from a zinc sulfate solution according to one embodiment of the present invention.

[0039] Referring to Fig. 2, the conditioning cake discharged from the conditioning process (S4) was fed into a repulping tank (10) together with a zinc solution. The amount of conditioning cake fed into the repulping tank (10) was 120 T / D (ton per day), and the metal composition contained in the conditioning cake was measured.

[0040] The composition ratio of copper (Cu), iron (Fe), zinc (Zn), arsenic (As), and lead (Pb) contained in the conditioning cake (%) T / DCu4.004.80Fe5.106.12Zn26.631.9As1.211.46Pb0.881.05

[0041] The repulping process performed in the repulping tank (10) was performed at 60°C for 1.5 hours, and the concentration of the conditioning cake among the solutions introduced into the repulping process was measured to be 143 g / L. Next, the repulping process effluent discharged from the repulping process was introduced into the liquid leaching process reactor (20), and the concentration of the repulping slurry included in the repulping process effluent was measured.

[0042] Concentration of copper (Cu), iron (Fe), zinc (Zn), arsenic (As), and lead (Pb) in the slurry after the repulping process Concentration (g / L) T / DCu8.217.76Fe8.958.45Zn147138.8As2.862.71Pb0.940.89

[0043] The above-mentioned post-pulping process liquid was fed into a liquid leaching process reactor (20) together with a zinc sulfate solution, and the concentration of sulfuric acid in the zinc sulfate solution was measured to be 85 g / L. The concentrations of copper, iron, and zinc arsenic in the zinc sulfate solution fed into the liquid leaching process reactor (20) were measured.

[0044] Concentrations of copper (Cu), iron (Fe), zinc (Zn), and arsenic (As) in the zinc sulfate solution used in the semen leaching process (g / L) T / DCu3.105.04Fe2.203.58Zn78.4127.5As1.802.93

[0045] The repulping process slurry fed into the liquid leaching process reactor (20) and the zinc sulfate solution were reacted at 65°C for 2 hours, and most of the copper was dissolved during this process. The concentrations and dissolution rates of copper (Cu), iron (Fe), zinc (Zn), arsenic (As), and lead (Pb) in the liquid leaching process slurry discharged from the liquid leaching process were measured. At this time, the final acidity of sulfuric acid (H2SO4) in the liquid leaching process slurry was measured to be 35 g / L.

[0046] Concentration of copper (Cu), iron (Fe), zinc (Zn), arsenic (As), and lead (Pb) in the leaching process after the semen extraction process Concentration (g / L) T / D Dissolution rate (%) Cu4.9812.875.9Fe4.6812.087.8Zn104266.397.2As2.195.6364.7Pb0.350.890.0

[0047] Referring to Table 4, it can be confirmed that in the liquid after the semen leaching process is completed, copper is dissolved by more than 75%, iron by more than 87%, and zinc by more than 97%. That is, most of the valuable metals (copper, zinc, iron) included in the conditioning cake are dissolved during the repulping process and the semen leaching process and exist in the form of ions in the zinc sulfate solution. The liquid after the semen leaching process is introduced into a fumer NT (Fumer NT, 30) after adding a zinc quencher to the liquid after the semen leaching process. The liquid after the semen leaching process is neutralized by the zinc quencher in the fumer NT (30). The composition of the zinc quencher introduced into the liquid after the semen leaching process is as shown in Table 5 below.

[0048] Composition concentration of zinc quencher added to the slurry after the semen leaching process (g / L) T / DCu7.526.72Fe6.005.36Zn24.121.5As1.571.40Pb1.100.98

[0049] In the fumer NT (30), the liquid after the semen leaching process and zinc quenching were reacted at 65°C for 1 hour, and the final acidity of the liquid after the semen leaching process was pH 2.5. The liquid discharged after the neutralization process in the fumer NT (30) passes through a thickener (40), and the solids are transferred to the outside, and the liquid-type liquid after the neutralization process is transferred to the sedimentation tank (50) of the weak acid leaching process, and is reintroduced into the weak acid leaching process described above. The reintroduced solution is then connected to a de-copperizing process, a conditioning process, a ferrous precipitation process, an electrolytic process, etc., and the copper (Cu), iron (Fe), and zinc (Zn) contained in the reintroduced solution can be recovered as metals through the de-copperizing process, the ferrous precipitation process, and the electrolytic process. In addition, the liquid after the liquid leaching process reintroduced to the weak acid leaching process can go through a conditioning process, a re-pulping process, a ferrous leaching process, etc. together with the newly injected zinc sulfate solution, and copper (Cu), iron (Fe), and zinc (Zn), etc. that were not recovered during this process can be recovered again. In other words, the by-product discharged in the form of a conditioning cake can go through the above-mentioned processes multiple times, and as the above processes are performed repeatedly, the recovery rate of copper (Cu), iron (Fe), and zinc (Zn) will also continuously increase.

[0050] While the present invention has been described in connection with certain embodiments herein, it should be understood that various modifications and variations can be made without departing from the spirit and scope of the invention, as understood by those skilled in the art. Furthermore, such modifications and variations are intended to fall within the scope of the claims appended to this specification.

Claims

1. A method for recovering copper from a zinc sulfate solution generated from a leaching process that dissolves zinc ore in sulfuric acid, A neutral leaching process for dissolving the above zinc ore; A weak acid leaching process in which the neutral leaching process liquid in which the zinc ore is dissolved is dissolved with sulfuric acid to produce a zinc sulfate solution; A de-copperizing process for removing copper dissolved in the zinc sulfate solution in the form of copper cement; A conditioning process for reducing the post-desorption process liquid discharged in the above-mentioned de-desorption process; A repulping process for repulping the conditioning cake, which is a solid material discharged from the above conditioning process, with a zinc solution; and It includes a liquid leaching process for dissolving copper contained in the repulping process slurry discharged from the above repulping process by dissolving the slurry discharged from the above repulping process with sulfuric acid. A method for recovering copper from a zinc sulfate solution, wherein the leaching process residue discharged from the above-mentioned leaching process is neutralized by adding zinc quenching agent and then returned to the above-mentioned weak acid leaching process.

2. In paragraph 1, A method for recovering copper from a zinc sulfate solution, wherein the zinc sulfate solution that has been reintroduced into the above-mentioned weak acid leaching process is reintroduced into the above-mentioned de-copperizing process.

3. In paragraph 1, The above conditioning process reduces the liquid after the de-freezing process to produce a liquid after the conditioning process. A method for recovering copper from a zinc sulfate solution, wherein the solution after the conditioning process is treated in a coolant and a filter, the discharged solution is used as an iron precipitation process input solution to be input into the iron precipitation process, and the solid matter is discharged as the conditioning cake.

4. In paragraph 3, A method for recovering copper from a zinc sulfate solution, wherein the above iron precipitation process input liquid is input into an iron precipitation process that recovers iron oxide through a pressure oxidation process.

5. In paragraph 4, The above iron precipitation process produces a post-iron precipitation process solution through the above pressure oxidation process, A method for recovering copper from a zinc sulfate solution, wherein the solution after the above iron precipitation process is treated in a coolant and a filter, the discharged solution is transferred to the above neutral leaching process, and the solid is discharged as iron oxide.

6. In paragraph 1, A method for recovering copper from a zinc sulfate solution, wherein the above repulping process is performed at a process temperature of 60°C to 80°C and a pH of 2.5 to 3.

0.

7. In paragraph 6, A method for recovering copper from a zinc sulfate solution, wherein in the repulping process, the concentration of the conditioning cake in the zinc solution is 100 g / L to 200 g / L.

8. In paragraph 1, A method for recovering copper from a zinc sulfate solution, wherein the concentration of sulfuric acid in the solution after the above-mentioned semen leaching process is 25 g / L to 50 g / L.

9. In paragraph 8, A method for recovering copper from a zinc sulfate solution, wherein in the above-mentioned semen leaching process, more than 85% of the copper contained in the conditioning cake is dissolved.

10. In paragraph 9, A method for recovering copper from a zinc sulfate solution, wherein 92% or more of iron and 98% or more of zinc contained in the conditioning cake are dissolved in the above-mentioned semen leaching process.

11. In paragraph 8, A method for recovering copper from a zinc sulfate solution, wherein the above-mentioned liquid leaching process is performed for 2 to 3 hours, the dissolution temperature is 60°C to 80°C, and the process pressure is 1 to 2 atm.

12. In paragraph 1, A method for recovering copper from a zinc sulfate solution, wherein the pH of the above weak acid leaching process is 2.5 to 3.

0.

13. In paragraph 12, A method for recovering copper from a zinc sulfate solution, wherein the process time of the above weak acid leaching process is 3 to 4 hours.

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