A short-process zinc copper slag leaching process for hydrometallurgical zinc production

Abstract

The present invention relates to a short-process zinc copper slag leaching process for hydrometallurgical zinc smelting. After pulping wash water with copper-cadmium-cobalt slag, it is transported to a cadmium recovery thickener. After controlling the pH for leaching reaction, copper slag is obtained by pressing through a filter press; in the copper slag pulping tank, zinc electrowinning electrolysis waste liquid is added to the copper slag, and the temperature is raised to obtain a pulped copper slag slurry; the copper slag slurry is transported to a copper slag pickling tank, and an appropriate amount of sulfuric acid is added to the tank to raise the temperature for reaction again, and then it is filtered through a filter press. After filtration, the filter cake is washed with industrial water to obtain wash water and zinc copper slag. The zinc content in the zinc copper slag is reduced to less than 4.5%. The wash water is recycled to the copper-cadmium-cobalt slag pulping tank, and the zinc copper slag is bagged and sold externally. The present invention effectively reduces the zinc content in the zinc copper slag, improves the grade of the zinc copper slag, increases the direct zinc recovery rate of the system, while improving the cadmium recovery rate, reducing the unit consumption of cadmium recovery cost, and enhancing the production efficiency.

Description

Technical Field

[0001] The present invention relates to a hydrometallurgical process for zinc extraction, and particularly to a short-process zinc copper slag leaching process for zinc hydrometallurgy. Background Art

[0002] In the neutral leaching process of zinc hydrometallurgy, most of the impurity metals such as Fe, As, Sb, and Ge can be removed from the solution through the neutralization hydrolysis process. However, impurities such as Cu, Cd, Co, and Ni in the solution cannot be removed in the neutral leaching stage. These impurities are harmful to zinc electrowinning and must be purified and removed by the zinc powder-antimony salt purification method before electrowinning. After purification, copper-cadmium-cobalt slag is produced, and the copper-cadmium-cobalt slag is sent to cadmium recovery for copper-cadmium recovery, thus producing zinc copper slag.

[0003] The zinc content in zinc copper slag affects the direct recovery rate of zinc. The high zinc content in copper slag also affects the Cu grade in zinc copper slag. The Cu grade in zinc copper slag directly affects the external sales price, and the zinc content in zinc copper slag is not priced during external sales, reducing the direct recovery rate of the zinc system. Therefore, the zinc content in zinc copper slag is an important index for comprehensive recovery in zinc smelting. Summary of the Invention

[0004] The present invention has developed a short-process zinc copper slag leaching process for zinc hydrometallurgy, which uses sulfuric acid as the leaching and acid washing agent, minimizes the use of zinc electrowinning electrolytic waste liquid in the copper-cadmium recovery process to reduce the Zn content and volume in the system during the copper-cadmium recovery process, avoids adding concentrated sulfuric acid for acid washing, reduces the use of electrowinning waste liquid, and reduces the volume of the copper slag acid washing system; adjustments have also been made in the recycling of the washing water for acid washing copper slag. The washing water is transported to the copper-cadmium-cobalt slag pulping tank in the purification process to replace the waste electrolyte for pulping copper-cadmium-cobalt slag. The premature leaching of copper-cadmium-cobalt slag can also significantly improve the leaching rate of Zn.

[0005] A short-process zinc copper slag leaching process for zinc hydrometallurgy is as follows:

[0006] (I) Copper-cadmium-cobalt slag leaching process

[0007] (1) Pulping of copper-cadmium-cobalt slag

[0008] The washing water obtained after pressure filtration of copper slag acid washing is transported to the copper-cadmium-cobalt slag pulping tank. Since the washing water has a high acid content, it can play a role in acidic leaching and pulping of copper-cadmium-cobalt slag in advance; the washing water is recycled, and there is no need to add zinc electrowinning electrolytic waste liquid to pulp copper-cadmium-cobalt slag. At the same time, the volume of the copper slag acid washing system is also reduced, which is beneficial to controlling the specific gravity and improving the leaching rate of zinc.

[0009] (2) Leaching of copper-cadmium-cobalt slag

[0010] The pulped copper-cadmium-cobalt residue slurry is transported to the cadmium recovery leaching thickener, where sulfuric acid and zinc electrowinning electrolytic waste liquid are added. The slurry overflows to the intermittent leaching tank, and the pH value is adjusted to 2 - 2.5 by adding zinc electrowinning electrolytic waste liquid. After reacting for two hours, the copper-cadmium-cobalt residue slurry is transported to the indoor leaching reaction tank, and the temperature of the indoor leaching tank is raised to 85°C for high-temperature and high-acid leaching.

[0011] (3) Replacement of zinc-copper slag

[0012] Leach for 7 - 8 hours, add 1 ton of cadmium recovery secondary replacement cadmium wool, and use the secondary replacement cadmium wool for copper replacement. The PH end point is controlled at 4.0 - 5.0, and the reaction formula is CuSO4 + Cd = CdSO4 + Cu. After the replacement in the leaching tank is completed, filter pressing is carried out to obtain zinc-copper slag filter cake and copper-removed filtrate after filter pressing. The zinc-copper slag filter cake enters the copper slag pulping tank, and the filtrate enters the subsequent process to recover cadmium and cobalt;

[0013] (II) Pickling process of zinc-copper slag

[0014] (4) Pulping of zinc-copper slag

[0015] The zinc-copper slag filter cake is added with waste electrolytic solution in the copper slag pulping tank according to a specific gravity of 1.4t / m 3 to obtain the pulped zinc-copper slag slurry, which is heated to 75°C and reacts for 4 hours;

[0016] (5) Pickling of copper slag

[0017] The zinc-copper slag slurry is transported to the zinc-copper slag pickling tank, where an appropriate amount of sulfuric acid is added and the temperature is raised to 90°C again. The reaction time is 3 - 4h. After filter pressing by a filter press, the filter cake is washed with industrial water after filter pressing to obtain wash water (filtrate after filter pressing) and zinc-copper slag filter cake. The zinc content in the zinc-copper slag is reduced to less than 4.5%. The wash water is transported to the purification copper-cadmium-cobalt slag pulping tank for recycling. The zinc-copper slag produced after the filter press discharges the slag is packed in ton bags and sold outside.

[0018] Advantages of the present invention:

[0019] 1. After the present invention is put into use, the average annual value of the zinc content in the copper slag is reduced from 10.14% to 4.25%, improving the comprehensive recovery rate of zinc.

[0020] 2. The present invention replaces the zinc electrowinning waste electrolytic solution with sulfuric acid + water for acid adjustment and pulping, reducing the use of waste electrolytic solution, indirectly reducing 50g / l of zinc in the zinc electrowinning electrolytic waste liquid from entering the recovery system, increasing the cadmium recovery rate, reducing the unit consumption of cadmium recovery cost, and improving the efficiency. Brief description of the drawings

[0021] Figure 1 It is the process flow chart of the present invention. Detailed implementation manners

[0022] Example 1

[0023] 1) Transfer the washing water to the copper-cadmium-cobalt slag pulping tank, and discharge the purified zinc powder replaced copper-cadmium-cobalt-nickel filter press residue to the copper-cadmium-cobalt slag pulping tank. After pulping for 0.5 - 1 h, obtain the copper-cadmium-cobalt slag slurry and transfer it to the cadmium recovery leaching thickener;

[0024] 2) The overflow of the cadmium recovery leaching thickener flows to the intermittent tank. After the liquid pouring is completed, the pH value of the copper-cadmium-cobalt slag slurry in the cadmium recovery leaching thickener rises to 5.0; Add sulfuric acid to adjust the pH value to 2.0 in the cadmium recovery leaching thickener, and add waste zinc electrowinning electrolytic waste liquid to adjust the pH value to 2.0 in the intermittent tank; Stir and react in the intermittent tank for 2 h and then pour the liquid into the leaching tank;

[0025] 3) Heat the leaching tank to 80 °C and stir and react for 6 - 8 h. Slowly add secondary replacement cadmium wool to adjust the pH value of the leaching tank to 5.0. After reacting for 0.5 h, add electrowinning electrolytic waste liquid to adjust the pH value to 4.5 and start transporting it to the filter press for filtration;

[0026] 4) The filtrate of the filter press is the post-leaching solution, containing Cu < 5 mg / L; The filter cake of the filter press is copper slag and the plate is opened to discharge the slag to the copper slag pulping tank. Add zinc electrowinning electrolytic waste liquid to the copper slag pulping tank and start heating with steam to 75 °C. After stirring and reacting for 2 h, transfer the slurry to the zinc-copper slag pickling tank;

[0027] 5) Add sulfuric acid to the zinc-copper slag pickling tank. The addition amount of sulfuric acid is adjusted according to the pH of the cadmium recovery leaching thickener. It is required that the pH is controlled at ≤ 3 after the cadmium recovery receives the copper-cadmium-cobalt slag slurry. Start heating with steam to 90 °C for high-temperature and high-acid leaching. After stirring and reacting for 4 h, start filtration,

[0028] 6) After the filtration is completed, the filter press automatically opens the plate to obtain washing water and zinc-copper slag. The washing water contains H2SO4: 197.62 g / L; The zinc-copper slag contains Cu: 39.72% and Zn: 3.79%.

[0029] The above has described the embodiments of the present invention in detail, but the content described is only the preferred embodiments of the present invention and cannot be considered as used to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A short-process zinc-copper slag leaching process for hydrometallurgical zinc production, characterized in that: The specific process is as follows: (1) Leaching process of zinc-copper slag (1) Pulping of copper-cadmium-cobalt slag The washing water after pickling copper slag is transported to the copper-cadmium-cobalt slag slurrying tank in the purification process, and the washing water and copper-cadmium-cobalt slag are slurried at a specific gravity of 1.2 t / m 3 to obtain a copper-cadmium-cobalt slag slurry; (2) Leaching of copper-cadmium-cobalt slag The pulped copper-cadmium-cobalt slag slurry is transported to the cadmium recovery leaching thickener, sulfuric acid and zinc electrowinning electrolysis waste liquid are added, the slurry overflows to the intermittent leaching tank, and the pH value is adjusted to 2 - 2.5 by adding zinc electrowinning electrolysis waste liquid. After reacting for two hours, the copper-cadmium-cobalt slag slurry is transported to the indoor leaching reaction tank, and the indoor leaching tank is heated to 85°C for high-temperature and high-acid leaching; (3) Replacement of zinc-copper slag After leaching for 7 - 8 hours, 1 ton of cadmium recovery secondary replacement cadmium cotton is added, and the secondary replacement cadmium cotton is used for copper removal by replacement. The pH end point is controlled at 4.0 - 5.

0. After the replacement in the leaching tank is completed, filtration is carried out to obtain the zinc-copper slag filter cake and the copper-removed filtrate after filtration. The zinc-copper slag filter cake enters the copper slag pulping tank, and the filtrate enters the subsequent process for cadmium and cobalt recovery; (2) Pickling process of zinc-copper slag (4) Pulping of zinc-copper slag The zinc-copper slag filter cake is placed in the copper slag slurring tank at a specific gravity of 1.4 t / m 3 Add waste electrolyte to obtain the slurried zinc-copper slag slurry, heat it to 75 °C, and react for 4 hours; (5) Pickling of zinc-copper slag The zinc-copper slag slurry is transported to the zinc-copper slag pickling tank, an appropriate amount of sulfuric acid is added to the tank and heated to 90°C again, the reaction time is 3 - 4h, and after filtration by a filter press, the filter cake is washed with industrial water after filtration to obtain wash water and the zinc-copper slag filter cake. The zinc content in the zinc-copper slag is reduced to less than 4.5%. The wash water is transported to the purification copper-cadmium-cobalt slag pulping tank for recycling, and the zinc-copper slag filter cake is packed in ton bags and sold outside; 2. The short-process zinc copper slag leaching process for zinc hydrometallurgy according to claim 1, wherein: In the first step and the fifth step, the acid content in the wash water is 200 - 300 g / L.

3. The short-process zinc and copper slag leaching process for zinc hydrometallurgy according to claim 1, characterized in that: In the second step, the end point pH of the cadmium recovery leaching thickener is 1.5 - 2.0, and the end point pH in the intermittent tank is 2.0 - 2.

5.

4. The short-process zinc and copper slag leaching process for zinc hydrometallurgy according to claim 1, wherein: In the second step, the leaching temperature is 80 - 85°C.

5. The short-process zinc-copper slag leaching process for hydrometallurgical zinc extraction according to claim 1, characterized in that: In the third step, the pH value is adjusted to 4.0 - 4.5 after adding cadmium cotton.

6. The short-process zinc and copper slag leaching process for zinc hydrometallurgy according to claim 1, characterized in that: In the fifth step, the temperature of the zinc-copper slag pickling tank is 90 - 95°C, and the addition amount of sulfuric acid is adjusted according to the pH of the cadmium recovery leaching thickener at 1.5 - 2.0.

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