Method for improving copper leaching rate in calcine leaching process

Abstract

The invention relates to a method for increasing the copper leaching rate in the calcine leaching process, and belongs to the technical field of hydrometallurgy. Under the condition that the main leaching process of copper-zinc-containing calcine is not changed, copper-zinc-containing calcine is leached step by step, an oxidizing agent is added after ferric iron is settled, the copper leaching rate can be increased by 10% or above at the high pH value of 4.5, and the copper leaching rate can be increased by 10% or above. According to the method, the recovery rate of the associated copper in the zinc concentrate is increased, the recovery of the associated copper in the zinc ore is realized with less energy consumption, the economic burden of the existing copper-containing zinc calcine leaching is not additionally increased, and the method has better economical efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrometallurgy. Specifically, it relates to a method for improving the leaching rate of copper during the leaching process of calcine. Background Art

[0002] During the process of hydrometallurgical zinc production, the recovery of associated metal copper is equivalent to additional output, which can bring additional profits to the company. Comprehensive recovery and utilization of it can improve the overall utilization efficiency of zinc ore resources and create new economic growth points. Compared with extracting copper metal from primary ore, recovering copper from associated metal zinc concentrate consumes less energy.

[0003] During the zinc ore treatment process, the leaching rate of copper in the oxidation step is relatively high, basically above 95%. The concentration of copper ions in the oxidation tank solution is relatively high, while the concentration of copper ions in the supernatant during neutral leaching decreases significantly. During the leaching process of copper-bearing zinc calcine, the concentration of copper ions in the solution decreases. In the 1st, 2nd, 3rd, and 4th barrels of neutral leaching, as the addition of copper-bearing zinc calcine increases, the pH value of the pulp gradually rises. When the pulp pH ≥ 4.2, the copper ions in the solution hydrolyze to form Cu(OH)2 precipitate and enter the bottom flow of the middle leaching. The greater the pH value, the more complete the hydrolysis and precipitation of copper ions. The pH of the neutral leaching of copper-bearing zinc calcine is usually 5.1 - 5.4, and the amount of copper hydrolysis and precipitation is relatively large, resulting in a relatively low concentration of copper ions in the middle supernatant.

[0004] During the leaching process of zinc calcine, in order to ensure the complete hydrolysis of iron while zinc does not hydrolyze, the pH value at the end of leaching is controlled at 5.2 - 5.4. However, at this pH value, copper will hydrolyze and precipitate, so it is impossible to take into account the leaching rate of copper. Summary of the Invention

[0005] In order to overcome the problems existing in the background art, the present invention provides a method for improving the leaching rate of copper during the leaching process of calcine, which can improve the leaching rate of copper while ensuring the hydrolysis and precipitation of iron and the leaching rate of zinc, and can improve the leaching rate of copper without changing the existing leaching process of copper-bearing zinc calcine, taking into account the recovery of both zinc and copper.

[0006] The method for improving the leaching rate of copper during the leaching process of calcine includes the following steps: (1) Continuously add copper-bearing zinc calcine to acid solution for leaching, and add manganese dioxide to the acid solution. When the acidity of the leaching solution is 15 - 20 g / L, stop adding copper-bearing zinc calcine and continue the reaction; (2) Continue to add copper-bearing zinc calcine. When the pH value of the leaching solution is 2.5 - 3.0, stop adding copper-bearing zinc calcine and continue the reaction; (3) Continue to add copper-bearing zinc calcine. When the pH value is 3.5 - 4.0, stop adding copper-bearing zinc calcine, and add an oxidant to the leaching solution and continue the reaction; (4) Continuously add copper-zinc calcine, control the leaching pH value not exceeding 4.5, and stop adding the calcine.

[0007] Further, the oxidant is any one of potassium permanganate, Na2S2O8 or hydrogen peroxide.

[0008] Further, when the oxidant is potassium permanganate, the addition amount of the oxidant is 0.25 - 0.5 g / L; when the oxidant is Na2S2O8, the addition amount of the oxidant is 1.5 - 2.25 g / L; when the oxidant is hydrogen peroxide, the addition amount of 20% hydrogen peroxide is 2 - 20 mL / L.

[0009] Further, the oxidant is potassium permanganate.

[0010] Further, after adding the oxidant in step (3), continue to react for 25 - 30 min.

[0011] Further, the reaction temperature for steps (1) to (4) is 85 - 88 °C.

[0012] Further, the addition amount of the manganese dioxide is 1.5 - 2.0 times the theoretical amount for completely oxidizing Fe in the acid solution of step (1) to Fe 2+ completely to Fe 3+ theoretical amount.

[0013] Further, the copper-zinc calcine is the pulverized copper-zinc calcine.

[0014] Further, the acid solution in step (1) is any one or a mixture of more than one of zinc electrolysis waste liquid, dilute sulfuric acid, the post-leaching solution of zinc oxide fume, the supernatant of acid leaching, and the filtrate of zinc sulfate for cobalt precipitation.

[0015] Further, the continuous reaction time for steps (1) to (4) is 10 - 30 min.

[0016] Advantages of the present invention: The method of the present invention can increase the leaching rate of copper in the copper-zinc calcine by more than 10%, and improve the recovery rate of associated copper in the zinc ore.

[0017] The method of the present invention improves the leaching of copper at a relatively high pH value, taking into account the recovery of both zinc and copper.

[0018] The method of the present invention realizes the recovery of copper without changing the leaching process of the copper-zinc calcine, does not consume additional energy, realizes the recovery of associated copper in the zinc ore with less energy consumption, does not additionally increase the economic burden of the existing leaching of the copper-zinc calcine, and has good economy. Description of the drawings

[0019] Figure 1 is a simplified process flow diagram of the present invention. Detailed implementation manners

[0020] In order to make the objectives, technical solutions and beneficial effects of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

[0021] The method for increasing the copper leaching rate during the roasting ore leaching process is to increase the copper leaching rate during the neutral leaching process of copper-zinc roasting ore, and without changing the existing leaching process of copper-zinc roasting ore, the copper leaching rate is increased, realizing the recovery of associated copper in zinc ore, and the copper leaching rate can be increased by more than 10% without affecting the zinc leaching. The specific steps are as follows: (1) Leach the copper-zinc roasting ore with sulfuric acid-containing acid solution, add manganese dioxide to the leachate, add copper-zinc roasting ore until the acidity is 15 - 20 g / L, stop adding copper-zinc roasting ore, and continue to react for 10 - 30 min. The main function of manganese dioxide is to oxidize ferrous iron to ferric iron, and the addition amount of manganese dioxide is 1.5 - 2.0 times the theoretical amount required to oxidize all ferrous iron in the acid solution to ferric iron.

[0022] (2) Continue to slowly add copper-zinc roasting ore. When the addition reaches a pH value of 2.5 - 3.0, stop adding copper-zinc roasting ore and continue to react for 10 - 30 min; (3) Continue to add copper-zinc roasting ore. When the pH value is 3.5 - 4.0, stop adding copper-zinc roasting ore. At a pH value of 3.5 - 4.0, ferric iron is basically completely precipitated. Add an oxidant to the leachate and continue to react for 10 - 30 min.

[0023] As the addition amount of copper-zinc roasting ore increases, the amount of zinc sulfide in the pulp increases equivalently, resulting in the reaction of copper ions in the solution with sulfide, and copper is reduced and forms a precipitate, causing the copper ion concentration in the middle supernatant to further decrease. By adding an oxidant, a high copper leaching can still be ensured when the pH value is raised to 4.5.

[0024] (4) Continue to add copper-zinc roasting ore. When the pH value is 4.5, stop adding copper-zinc roasting ore. By adding an oxidant, the copper leaching rate can be increased by more than 10%.

[0025] (5) Filter to obtain a copper-containing leachate.

[0026] To illustrate the present invention more clearly, the following examples are used for detailed description. Example 1

[0027] Step 1: preparing acid solution: preparing copper-zinc roasted sand leaching acid solution in combination with the production process parameters of the copper-zinc roasted sand leaching section; Step 2: Prepare copper-zinc roasted sand, take the copper-zinc roasted sand from production, grind it, and control the particle size to be less than 200 mesh and ≥80% by weight (i.e., particle size <75μm≥80%); Step 3: Calculate the oxidized Fe 2+ To add manganese powder (powdered manganese dioxide), follow the steps in step 1 to add Fe 2+ The content calculation needs to consume 1.8 times the theoretical amount of manganese powder, weigh it and set it aside; Step 4: Conduct leaching reaction: Heat the acid solution in a water bath at 85°C, start stirring at 400r / min, and add the manganese powder weighed in step 3. The entire leaching process is divided into four stages: (1) In the first stage, the leaching acid is controlled at 15-20g / L. The amount of copper-zinc roasted sand to be added is calculated according to the acid content of the acid solution and the acid consumption rate of the copper-zinc roasted sand. The copper-zinc roasted sand is slowly added. After the addition of the copper-zinc roasted sand is completed, the reaction is continued for 25 minutes before the second stage reaction begins. (2) In the second stage, the pH is controlled at 2.5-3.0, and the copper-zinc roasted sand is slowly added. The pH test paper is used to detect that when the pH reaches 2.5-3.0, the addition of the copper-zinc roasted sand is stopped. The reaction is continued for 25 minutes before the third stage reaction is conducted. (3) In the third stage, the pH is controlled at 3.5-4.0, and copper-zinc roasted sand is slowly added. The pH is tested with pH test paper. When the pH reaches 3.5-4.0, the addition of copper-zinc roasted sand is stopped. An oxidant (H2O2, potassium permanganate or sodium persulfate) is added to react for 25 minutes, and then the fourth stage of reaction is carried out. (4) In the fourth stage, the pH is controlled at 4.5, and copper-zinc roasted sand is slowly added. When the pH reaches 4.5, the addition of copper-zinc roasted sand is stopped. The reaction is continued for 25 minutes, and the reaction is completed.

[0028] Step 5: Filter, send the filtrate to analyze the Cu content, and send the filter residue to the acid leaching section of copper-zinc roasted sand.

[0029] The following table shows the effects of different oxidants and oxidant dosage on copper leaching rate.

[0030] Effect of oxidant and oxidant dosage on copper leaching rate

[0031] It can be seen from the gradient reaction that, combined with the economic cost analysis, the optimal amount of oxidant added is: Na2S2O8 (pure): 1.75g / L solution; H2O2 (20%): 16ml / l solution; KMnO4 (pure): 0.75g / L.

[0032] The addition of the oxidant has little effect on the zinc leaching rate, indicating that the present invention does not affect the zinc leaching while increasing the copper leaching rate.

[0033] Under the condition of neutral leaching of copper-zinc calcine at pH 4.5, the order of the improvement effect of three oxidants on the copper leaching rate is: potassium permanganate > sodium persulfate > hydrogen peroxide. Taking KMnO4 as the oxidant, the dosage of the oxidant is the least and the copper leaching rate is higher. Potassium permanganate is preferably used as the oxidant.

[0034] The following further illustrates the present invention with specific implementation cases: Example 2

[0035] Prepare the acid solution, combined with the production process parameters of the copper-zinc calcine leaching section: the starting flow rate is 250 - 350 m 3 / h, the matching amount of the supernatant of acid leaching is 130 - 160 m 3 / h, the flow rate of the second neutralized solution (the leaching solution after zinc oxide dust) is 30 - 45 m 3 / h, the zinc electrolysis waste liquid is 60 - 90 m 3 / h, the cobalt precipitation filtrate of zinc sulfate is 25 - 40 m 3 / h, configure according to the combined composition ratio, and adjust the addition amount of the waste liquid to control the H2SO4 content in the pre-leaching solution to reach 85 g / L. The final composition of the acid solution: H2SO4: 80 g / L, Cu 2+ : 195 mg / L, Fe 2+ : 573 mg / L, Zn 2+ : 79 g / L; (2) Prepare copper-zinc calcine, with Cu: 0.72%, grind it, and control the particle size to be less than 200 mesh and the weight to be ≥ 80%; (3) Oxidize Fe 2+ The manganese powder to be added is calculated according to 1.8 times the theoretical amount of manganese powder required to consume the Fe 2+ content in the acid solution. Weigh 0.64 g of manganese powder (400 ml of acid solution) and set it aside; (4) Conduct the leaching reaction. Take 400 ml of acid solution and heat it with a water bath at a heating temperature of 85°C. Start stirring with a stirring intensity of 400 r / min. Add the manganese powder weighed in step 3. The entire leaching process is divided into four stages. In the first stage, control the leaching acid to be 15 - 20 g / L. Calculate the addition amount of copper-zinc calcine according to the acid content in the acid solution and the acid consumption rate of copper-zinc calcine. Weigh the copper-zinc calcine and slowly add it. After reacting for 25 min, start the second stage; in the second stage, control the pH to be 2.5 - 3.0, slowly add the copper-zinc calcine, and use pH test paper to detect. When the pH reaches 2.5 - 3.0, stop adding the copper-zinc calcine. After reacting for 25 min, start the third-stage reaction; in the third stage, control the pH to be 3.5 - 4.0, slowly add the copper-zinc calcine, and use pH test paper to detect. When the pH reaches 3.5 - 4.0, stop adding the copper-zinc calcine. Add 0.3 g of oxidant potassium permanganate (for 400 ml of acid solution) and react for 25 min, then start the fourth-stage reaction; in the fourth stage, control the pH to be 4.5, slowly add the copper-zinc calcine. When the pH reaches 4.5, stop adding the copper-zinc calcine. Stat the addition amount of calcine (55 g). After reacting for 25 min, the reaction ends. (5) Filter. Send the filtrate for sample analysis. The volume of the filtrate is 365 mL, the Cu content is 632 mg / L, the zinc content is 142 g / L, the zinc leaching rate is 66.87%, and the copper leaching rate is 56.28%.

[0036] Comparative Example 1 (without adding oxidant) Under the same conditions and steps as in Example 2, change the condition control of the leaching reaction. Specifically: Take 400 ml of acid solution and heat it with a water bath at a heating temperature of 85°C. Start stirring with a stirring intensity of 400 r / min. Add the manganese powder weighed in step 3. The entire leaching process is divided into four stages. In the first stage, control the leaching acid to be 15 - 20 g / L. Calculate the addition amount of copper-zinc calcine according to the acid content in the acid solution and the acid consumption rate of copper-zinc calcine. Weigh the copper-zinc calcine and slowly add it. After reacting for 25 min, start the second stage; in the second stage, control the pH to be 2.5 - 3.0, slowly add the copper-zinc calcine, and use pH test paper to detect. When the pH reaches 2.5 - 3.0, stop adding the copper-zinc calcine. After reacting for 25 min, start the third-stage reaction; in the third stage, control the pH to be 3.5 - 4.0, slowly add the copper-zinc calcine, and use pH test paper to detect. When the pH reaches 3.5 - 4.0, stop adding the copper-zinc calcine, and start the fourth-stage reaction; in the fourth stage, control the pH to be 4.5, slowly add the copper-zinc calcine. When the pH reaches 4.5, stop adding the copper-zinc calcine. Stat the addition amount of calcine (55 g). After reacting for 25 min, filter. The volume of the leaching solution is 360 mL. The leaching solution contains 513 mg / L of copper and 142 g / L of zinc. The zinc leaching rate is 66.87%, and the copper leaching rate is 44.67%.

[0037] Comparative Example 2 Under the same conditions as in Example 2, the pH value at the end point of the fourth stage was increased to 5.2, specifically as follows: Take 400 ml of acid solution and heat it with a water bath. The heating temperature is 85 °C. Start stirring with a stirring intensity of 400 r / min. Add the manganese powder weighed in Step 3. The entire leaching process is divided into four stages. In the first stage, control the leaching acid to be 15 - 20 g / L. Calculate the addition amount of copper-zinc calcine according to the acid content in the acid solution and the acid consumption rate of copper-zinc calcine. Weigh the copper-zinc calcine and slowly add the copper-zinc calcine. After reacting for 25 min, start the second stage; in the second stage, control the pH to be 2.5 - 3.0, slowly add the copper-zinc calcine, and use pH test paper to detect. When the pH reaches 2.5 - 3.0, stop adding the copper-zinc calcine. After reacting for 25 min, start the third stage of reaction; in the third stage, control the pH to be 3.5 - 4.0, slowly add the copper-zinc calcine, and use pH test paper to detect. When the pH reaches 3.5 - 4.0, stop adding the copper-zinc calcine. Add 0.3 g of oxidant potassium permanganate (for 400 ml of acid solution) and react for 25 min, then start the fourth stage of reaction; in the fourth stage, control the pH to be 4.5, slowly add the copper-zinc calcine, count the addition amount of calcine (59 g), use pH test paper to detect. When the pH reaches 5.2, stop adding the copper-zinc calcine. After reacting for 25 min, filter to obtain 365 L of filtrate. The copper content in the filtrate is 498 mg / L, the zinc content is 141 g / L, the copper leaching rate is 41.03%, and the zinc leaching rate is 61.22%. The copper leaching rate decreased significantly, and the zinc leaching rate decreased.

[0038] Theoretically, the pH value at which Fe 3+ starts to hydrolyze is 3.5, and the pH value at which hydrolysis is complete is 5.2. However, during the experiment, the concentration of Fe 3+ is relatively low, and the pH at which hydrolysis is complete will decrease. Therefore, the experimental control end point pH is 4.5, which not only meets the conditions for zinc leaching and Fe 3+ hydrolysis, but also reduces the amount of Cu 2+ hydrolyzed and precipitated into the slag. Increasing the end point pH value, the decrease in the zinc leaching rate is mainly due to the increase in pH, and part of the zinc hydrolyzes into the slag, resulting in a decrease in the zinc content in the solution. Example 3

[0039] (1) Prepare the acid solution, combined with the production process parameters of the copper-zinc calcine leaching section: the start-up flow rate is 250 - 350 m 3 / h, the acid supernatant matching amount is 130 - 160 m 3 / h, the flow rate of the second neutralization filtrate is 30 - 45 m 3 / h, the waste liquid is 60 - 90 m 3 / h, the cobalt precipitation filtrate is 25 - 40 m 3 / h, and configure according to the composition ratio, adjust the addition amount of the waste liquid to control the H2SO4 content in the pre-leaching solution to reach 85 g / L. The final acid solution composition: H2SO4: 81 g / L, Cu2+ : 203 mg / L, Fe 2+ : 721 mg / L; (2) Prepare copper-zinc calcine, with Cu: 0.72%, ground, particle size controlled to be less than 200 mesh, weight ≥ 80%; (3) Oxidize Fe 2+ The manganese powder to be added is calculated according to 1.6 times the theoretical amount of manganese powder consumed based on the Fe content in the acid solution. Weigh 0.71 g of manganese powder (400 ml of acid solution) and set aside; 2+ (4) Conduct the leaching reaction. Take 400 ml of acid solution and heat it with a water bath. The heating temperature is 85 °C. Start stirring with a stirring intensity of 400 r / min. Add the manganese powder weighed in step 3. The entire leaching process is divided into four stages. In the first stage, control the leaching acid to be 15 - 20 g / L. Calculate the addition amount of copper-zinc calcine according to the acid content in the acid solution and the acid consumption rate of copper-zinc calcine. Weigh the copper-zinc calcine and slowly add it. After reacting for 25 min, start the second stage; in the second stage, control the pH to be 2.5 - 3.0. Slowly add the copper-zinc calcine and use pH test paper to detect. When the pH reaches 2.5 - 3.0, stop adding the copper-zinc calcine. After reacting for 25 min, start the third stage reaction; in the third stage, control the pH to be 3.5 - 4.0. Slowly add the copper-zinc calcine and use pH test paper to detect. When the pH reaches 3.5 - 4.0, stop adding the copper-zinc calcine. Add 0.7 g of oxidant sodium persulfate (400 ml of acid solution) and react for 25 min, then start the fourth stage reaction; in the fourth stage, control the pH to be 4.5. Slowly add the copper-zinc calcine and record the addition amount of calcine (55 g). When the pH reaches 4.5, stop adding the copper-zinc calcine. After reacting for 25 min, the reaction ends.

[0040] (5) Filter and send the filtrate for sample analysis: The filtrate is 360 L, the Cu content is 569 mg / L; the zinc content is 142 g / L, the copper leaching rate is 49.76%, and the zinc leaching rate is 64.53%.

[0041] Under the same conditions without adding an oxidant, 360 L of filtrate is obtained, the Cu content is 448 mg / L, the zinc content is 142 g / L, the copper leaching rate is 38.76%, and the zinc leaching rate is 64.53%. Example 4

[0042] (1) Prepare the acid solution, combining the production process parameters of the copper-zinc calcine leaching section: start-up flow rate 250 - 350 m 3 / h, acid supernatant matching amount 130 - 160 m 3 / h, secondary neutralization filtrate flow rate 30 - 45 m 3 / h, waste liquid 60 - 90 m 3 / h, cobalt precipitation filtrate 25 - 40 m 3 / h, configure according to the composition ratio, and adjust the addition amount of the waste liquid to control the H2SO4 content in the pre-leaching solution to reach 85 g / L. Final acid solution composition: H2SO4: 81 g / L, Cu 2+ : 194 mg / L, Fe 2+ : 673 mg / L; (2) Prepare copper-zinc calcine. Take the copper-zinc calcine in production, with Cu: 0.72%, grind it, and control the particle size to be less than 200 mesh and the weight to be ≥ 80%; (3) Oxidize Fe 2+ The manganese powder to be added is calculated as 2.0 times the theoretical amount of manganese powder required according to the Fe content in the acid solution. Weigh 0.83 g of manganese powder (400 ml of acid solution) and set it aside; 2+ (4) Carry out the leaching reaction. Take 400 ml of the acid solution and heat it with a water bath at a heating temperature of 85 °C. Start stirring with a stirring intensity of 400 r / min, and add the manganese powder weighed in step 3. The whole leaching process is divided into four stages. In the first stage, control the leaching acid to be 15 - 20 g / L, calculate the addition amount of the copper-zinc calcine according to the acid content in the acid solution and the acid consumption rate of the copper-zinc calcine, weigh the copper-zinc calcine, and slowly add the copper-zinc calcine. After reacting for 25 min, start the second stage; in the second stage, control the pH to be 2.5 - 3.0, slowly add the copper-zinc calcine, and use pH test paper to detect. When the pH reaches 2.5 - 3.0, stop adding the copper-zinc calcine. After reacting for 25 min, start the third stage of the reaction; in the third stage, control the pH to be 3.5 - 4.0, slowly add the copper-zinc calcine, and use pH test paper to detect. When the pH reaches 3.5 - 4.0, stop adding the copper-zinc calcine, add 6.5 ml of oxidant hydrogen peroxide (400 ml of acid solution), and after reacting for 25 min, start the fourth stage of the reaction; in the fourth stage, control the pH to be 4.5, slowly add the copper-zinc calcine, count the addition amount of the calcine (55 g), and when the pH reaches 4.5, stop adding the copper-zinc calcine. After reacting for 25 min, the reaction ends. (5) Filter, and send the filtrate for sample analysis: The filtrate is 360 L, the Cu content is 492 mg / L; the zinc content is 142 g / L, the copper leaching rate is 42.76%, and the zinc leaching rate is 64.53%.

[0043] Under the same conditions without adding an oxidant, 360 L of filtrate is obtained, the Cu content is 396 mg / L, the zinc content is 141 g / L, the copper leaching rate is 34.03%, and the zinc leaching rate is 63.34%.

[0044]

[0045] Note: It should be noted that for the method of the present invention, the continued reaction time after stopping the addition of copper-zinc calcine in each step is based on the complete reaction of the added copper-zinc calcine. The continued reaction time of 10 minutes to 30 minutes in this application is limited by the existing production device of the applicant of the present invention. When the production capacity of the device changes, the continued reaction time needs to be adjusted according to the actual situation. The continued reaction time of each step of the present invention should not be understood as a necessary limitation on the method of the present invention.

[0046] In addition, it should be noted that the addition of manganese dioxide in the present invention is mainly to achieve the oxidation of iron, that is, to oxidize divalent iron to trivalent iron so that iron precipitates under the conditions of pH 3.5 to 4.0. This operation is a conventional operation for the neutral leaching of copper-zinc calcine and is not a necessary operation to improve the copper leaching rate. The amount of manganese dioxide added only needs to meet the complete oxidation of divalent iron, and its added amount should not be understood as a necessary control index for improving the copper leaching rate of the present invention.

[0047] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for improving the copper leaching rate during the roasting ore leaching process, characterized in that, It includes the following steps: (1) Continuously add copper-zinc calcine to the acid solution for leaching, and add manganese dioxide to the acid solution. When the acidity of the leaching solution is 15 - 20 g / L, stop adding copper-zinc calcine and continue the reaction; (2) Continue to add copper-zinc calcine. When the pH value of the leaching solution is 2.5 - 3.0, stop adding copper-zinc calcine and continue the reaction; (3) Continue to add copper-zinc calcine. When the pH value is 3.5 - 4.0, stop adding copper-zinc calcine, and add an oxidant to the leaching solution and continue the reaction; (4) Continue to add copper-zinc calcine, control the leaching pH value not exceeding 4.5, and stop adding the calcine.

2. The method according to claim 1, wherein The oxidant is any one of potassium permanganate, Na2S2O8 or hydrogen peroxide.

3. The method according to claim 2, wherein When the oxidant is potassium permanganate, the addition amount of the oxidant is 0.25 - 0.5 g / L; when the oxidant is Na2S2O8, the addition amount of the oxidant is 1.5 - 2.25 g / L; when the oxidant is hydrogen peroxide, the addition amount of 20% hydrogen peroxide is 2 - 20 mL / L.

4. The method according to claim 2 or 3, characterized in that The oxidant is potassium permanganate.

5. The method according to claim 1, wherein After adding the oxidant in step (3), continue the reaction for 25 - 30 min.

6. The method according to any one of claims 1, 2, 3 or 5, characterized in that The reaction temperature for steps (1) to (4) is 85 - 88 °C.

7. The method according to any one of claims 1, 2, 3 or 5, characterized in that The addition amount of the manganese dioxide is such that Fe in the acid solution in step (1) is 2+ completely oxidized to Fe 3+ 1.5 - 2.0 times the theoretical amount.

8. The method according to claim 1, characterized in that, The copper-zinc calcine mentioned is the pulverized copper-zinc calcine.

9. The method according to claim 1, characterized in that, The acid solution in step (1) is any one or a mixture of multiple ones among zinc electrolysis waste liquid, dilute sulfuric acid, the post-leaching solution of zinc oxide dust, the supernatant of acid leaching, and the filtrate of cobalt precipitation from zinc sulfate.

10. The method according to claim 1, characterized in that, The continuation reaction time for steps (1) to (4) is 10 - 30 min.

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