Circulating dechlorination method for recovering copper from oxygen pressure leaching feed liquid

Abstract

The invention provides a cyclic dechlorination method for recovering copper from oxygen pressure leached liquid, which comprises the steps of pretreatment, dechlorination, replacement and post-treatment, and specifically comprises the following steps: clarifying and separating the oxygen pressure leached liquid to obtain a material supernatant a; adding a dechlorinating agent, namely fresh copper slag, into the material a, and then carrying out dechlorination reaction at the temperature of 70-75 DEG C for 30-40 minutes to obtain cuprous chloride precipitate b and dechlorinated slurry c; adding a displacer into the dechlorinated slurry c to displace and deposit copper to obtain copper deposition slurry d; settling the copper deposition slurry d in a settling tank to obtain supernate e and underflow f; one part of the settled underflow f is pumped to the dechlorination step for circulation, one part of the settled underflow f is pumped into a filter press, material copper slag g is obtained after filter pressing, and filter pressing liquid is sent to the main process. According to the invention, continuous circulating dechlorination which can be really applied to actual production in a main system is realized.

Description

Technical Field

[0001] The invention belongs to the field of metallurgy, and in particular relates to a circulating dechlorination method for recovering copper from oxygen pressure leaching solution. Background Art

[0002] Oxygen pressure leaching of zinc sulfide concentrate involves the direct conversion of sulfides into sulfate and elemental sulfur by oxygenating the concentrate in an autoclave at high temperatures (140-160°C) and high pressures (350-1300 kPa) without roasting. This process overcomes the shortcomings of the "roasting-leaching-electrodeposition" process, such as complexity, length, and SO2 flue gas pollution. It offers advantages such as minimal environmental pollution, sulfur recovery as elemental sulfur, high zinc recovery rates, and good process adaptability.

[0003] Currently, over 75% of zinc in my country is produced using hydrometallurgical zinc smelting. During the oxygen-pressure leaching process, chloride ions accumulate in the zinc concentrate solution, reaching concentrations as high as 600-1800 mg / l. High chloride concentrations in the oxygen-pressure leaching solution can disrupt the subsequent zinc electrowinning process. Chloride ions generated during the electrowinning process are oxidized into chlorine gas at the anode, which corrodes the lead anode. This not only severely corrodes the lead anode, making zinc stripping difficult, but also increases power consumption at the anode and leads to higher lead content in the cathode zinc. Increased chloride levels above the electrolytic cell degrade operating conditions, severely impacting the operating environment and worker health. According to process requirements, the chloride ion content in the zinc solution during electrolysis should be controlled below 200 mg / l to ensure smooth production. Otherwise, it can negatively impact zinc electrowinning efficiency and the quality of the electrolytic zinc product. Therefore, the zinc electrolyte requires dechlorination. Conventional wet dechlorination in current production enterprises, some enterprises add the copper slag obtained from the cadmium recovery section of the purification auxiliary process to other sections for dechlorination, and some enterprises use waste liquid to add copper slag for intermittent dechlorination, all of which belong to intermittent dechlorination in the auxiliary process. Existing dechlorination technologies include: 1. Silver sulfate precipitation method: Silver sulfate precipitation method is to add silver sulfate to a chloride-containing solution to react with chloride ions to form insoluble silver chloride precipitate. Although this method is simple to operate and has good chlorine removal effect, it is not suitable for large-scale application due to the high price of silver salts, low silver regeneration recovery rate and high cost.

[0004] 2. Copper slag dechlorination method. The copper slag dechlorination method is based on the interaction between copper and copper ions and chloride ions in the solution to form insoluble cuprous chloride precipitates. However, in order to generate cuprous chloride precipitates from chloride ions in the solution, it is necessary to establish a balance point between copper and copper ions. In actual production, the copper slag is stored for different lengths of time, making it difficult to establish a balance point between sponge copper and oxidized copper.

[0005] 3. Ion exchange method. Ion exchange method for chlorine removal utilizes the exchangeable ions of ion exchange resin to react with the chloride ions to be removed in the solution, so that the chloride ions to be removed in the solution are adsorbed on the resin, and the corresponding exchangeable ions on the resin enter the solution. This method has a low chlorine removal efficiency of only about 50%, and the regeneration of the resin consumes a lot of water. The chloride ion content in the regenerated liquid is low, which brings a greater economic burden to the treatment of the regenerated liquid in the next step.

[0006] 4. Flocculation precipitation: Add an appropriate amount of flocculant, such as aluminum sulfate or polyferric sulfate, to the electrolyte to promote the combination of chloride ions and flocculants to form flocs, and then separate the flocs from the solution by precipitation.

[0007] 5. Electrodialysis: Electrodialysis uses electric field forces to separate chloride ions from the electrolyte. When the electrolyte passes through the electrodialyzer, the chloride ions migrate to the other side under the action of the electric field, thus achieving separation.

[0008] 6. Membrane separation: Use nanofiltration or reverse osmosis membrane technology to filter the electrolyte. Chloride ions and other small molecules are retained by the membrane, while zinc ions and other large molecules pass through the membrane, thus achieving separation.

[0009] 7. Evaporation crystallization: If the chloride ion concentration is high, the chloride ions can be separated in solid form through evaporation crystallization. The electrolyte is heated to a certain temperature to evaporate the water, and the chloride ions combine with zinc ions to form crystals. The solid chloride compound is then obtained through cooling crystallization and centrifugal separation.

[0010] Among the many dechlorination methods mentioned above, copper slag dechlorination is still the most commonly used method in industrial production. However, in practice, cuprous oxide is unstable and easily oxidized to divalent copper by oxygen in the air. This disrupts the dechlorination cycle and makes the process difficult to control. This ultimately leads to problems such as poor dechlorination effectiveness, low copper slag utilization, and easy deactivation of copper slag. Therefore, it is imperative to develop a method that can solve these technical problems. Summary of the Invention

[0011] The object of the present invention is to provide a circulating dechlorination method for recovering copper from oxygen pressure leaching solution.

[0012] The object of the present invention is achieved in that the method for recycling copper by dechlorination from oxygen pressure leaching solution comprises the steps of pre-treatment, dechlorination, replacement and post-treatment, specifically comprising: A. Pretreatment: Clarify and separate the oxygen pressure leaching liquid to obtain the material supernatant a; B. Dechlorination: Add fresh copper slag as a dechlorinating agent to material a and perform dechlorination reaction at 70-75°C for 30-40 minutes to obtain cuprous chloride precipitate b and dechlorinated slurry c; The fresh copper slag is fresh copper slag in which the elemental copper contained in the copper slag has not been oxidized by air; C. Replacement: adding a replacement agent to the dechlorinated slurry c to replace the copper slurry to obtain copper slurry d; D. Post-processing: 1) The copper slurry d is settled in a settling tank to obtain a supernatant e and an underflow f; 2) A portion of the bottom flow f after sedimentation is pumped to the dechlorination step for circulation; 3) A portion of the underflow is pumped into the filter press, and after filtration, the material copper slag g is obtained, and the filtrate is sent to the main process.

[0013] The specific operations are as follows: The supernatant after concentrated oxygen pressure leaching is continuously fed into the No. 1 copper precipitation tank and stirred. During the stirring process, a dechlorination agent, namely new copper slag, is added to dechlorinate the solution until the chlorine content is less than 200 mg / L. The dechlorinated slurry (from the outlet of the No. 1 copper precipitation tank) flows by gravity to the No. 2 copper precipitation tank and stirred. During the stirring process, a copper removal agent, namely iron powder, is continuously added to precipitate copper. After the copper precipitation is carried out for a certain period of time, the copper content of the solution in the No. 2 copper precipitation tank is sampled and analyzed. The copper ion content of the solution is controlled at 0.1-0.05 g / L (for purification and impurity removal in the subsequent process). The copper precipitation slurry flows by gravity (or is pumped) to the sedimentation tank for liquid-solid separation, and the supernatant of the sedimentation tank overflows into the supernatant storage tank (providing solution for subsequent work sections); a small part of the bottom flow (new copper slag) after sedimentation is pumped to the 1# copper precipitation tank for circulating dechlorination, and most of the bottom flow after sedimentation is pumped to the copper slag for a first filter press to obtain new copper slag and copper removal filtrate. The copper removal filtrate is pumped into the supernatant storage tank (providing solution for subsequent work sections), and the new copper slag is slurried and washed with production water or weak acid washing water. The washing slurry is pumped to the copper slag for secondary filter press. After filtration, copper slag with a copper content of more than 65% and washing liquid are obtained. The copper slag here is directly exported as a product, and the washing liquid is returned to the main process or used as slurry.

[0014] This invention is an innovative copper slag dechlorination method. It utilizes a single-step copper precipitation and chlorine removal process at the source of the main oxygen pressure leaching process. Iron powder is used to displace the precipitated copper. Under a certain acidity, new copper slag is obtained and returned to the first copper precipitation tank for cyclic dechlorination. This achieves continuous cyclic dechlorination in the main system that can be truly applied in actual production.

[0015] This method replaces the traditional waste liquid dechlorination process, which not only shortens the process flow and reduces losses, but also efficiently recovers copper and removes chlorine, reduces system equipment and pipeline corrosion, prolongs the service life of the electrolytic anode plate, and produces new liquid with low chlorine content and ensures 0 #Zinc product quality. Such a method not only reduces investment costs but also saves production and operation costs. The present invention specifically provides a method for dechlorination in oxygen pressure leaching liquid with simple process, low production cost, high copper recovery rate and chlorine removal rate, short process flow, simple operation, environmental protection and energy saving, which can be truly applied to actual production. The present invention is mainly aimed at the innovative invention of copper slag dechlorination method, which adopts one-step copper precipitation and chlorine removal at the source of the main process of oxygen pressure leaching, and uses iron powder to replace the copper precipitation. Under a certain acidity, new copper slag is obtained and returned to the 1# copper precipitation tank for cyclic dechlorination. Thus, continuous cyclic dechlorination that can be truly applied to actual production is achieved in the main system.

[0016] The specific technical principles of the present invention are as follows: 1) Fresh copper slag: Compared with the copper-cadmium slag used in the prior art (which is stored for a period of time and the elemental metal Cu is oxidized by contact with air), the elemental copper contained in fresh copper slag is not oxidized by air and is more active.

[0017] Using copper slag as a dechlorination agent, the principle of cuprous chloride dechlorination is to dissolve the copper in the copper slag into the acid solution, and the copper ions in the solution react with the copper to form cuprous ions to remove chlorine. The reaction equation is:

[0018] According to the Cu + The method is divided into three types according to the source: ① copper-cadmium slag produced in the purification section of wet zinc smelting; ② active copper produced by zinc powder reducing copper sulfate; ③ cuprous oxide dechlorination agent.

[0019] CuCl formation and pH, [Cu] T 、[Cl - ]related.

[0020] In Cu-Cl - -H2O system, Cu 2+ and Cu + Will form a series of complexes CuCl with chloride ions respectively - 、CuCl2 - 、CuCl3 2- 、CuCl 3- et al. calculated that the dechlorination limit of cuprous chloride purification is 0.04 g / L. A small-scale experiment was conducted using a zinc leachate containing 0.150 g / L of chlorine. The addition of zinc powder was 3 g / L, copper sulfate pentahydrate was 28 g / L, pH = 1.0, and the reaction temperature was 40°C for 1 hour, resulting in a removal rate of approximately 60%.

[0021] 2) During the replacement step, the 1# and 2# copper sinking tanks are arranged in a stepped arrangement using pipes in series. The height difference allows the slurry from the 1# copper sinking tank to flow by gravity into the 2# copper sinking tank after dechlorination, where it is replaced with iron powder for copper deposition. Iron powder is added to the 2# copper sinking tank continuously using an electronic scale (or added after slurry mixing). Depending on the copper content in the solution, 1.0-1.2 times the theoretical amount of iron powder is added. Copper deposition takes 30-40 minutes. Samples are then taken every hour for analysis of the copper content in the 2# copper sinking tank solution. The copper ion content of the solution after copper deposition is controlled at 0.1-0.15 g / L.

[0022] The 2# copper slurry tank and the settling tank are arranged in series in a stepped manner, utilizing the height difference to allow the copper slurry in the 2# copper slurry tank to flow through the chute to the settling tank. In the settling tank, the copper slurry particles use gravity to settle over a period of time, achieving liquid-solid separation.

[0023] 3) In the prior art, copper slag obtained from the cadmium recovery process (auxiliary process) is slurried and then dechlorinated. Some companies use copper-cadmium slag from the hydrometallurgical zinc purification process as raw material to dechlorinate a portion of the wastewater in the auxiliary process. However, in the present invention, the concentrated supernatant from oxygen pressure leaching is continuously pumped into the first copper precipitation tank, where copper slag (fresh copper slag) is added for dechlorination. The dechlorinated slurry then flows by gravity into the second copper precipitation tank, where iron powder is added to displace the copper slag. The copper slurry then enters a settling tank for sedimentation. A small portion of the settled underflow (fresh copper slag) is pumped to the first copper precipitation tank for cyclic dechlorination, while the remaining underflow is pumped into a filter press for a primary filtration. The filtrate is then fed into the main process. After slurry washing, the filter residue is pumped into a secondary filter press to produce copper slag for sale, and the filtrate is returned to the main process for reuse. The supernatant from the settling tank is fed into the next process in the main process. This demonstrates the realization of both copper precipitation and cyclic dechlorination at the source of the main oxygen pressure leaching process.

[0024] 4) The concentrated supernatant of the one-stage oxygen pressure leaching solution of the present invention contains copper greater than 1000 mg / l, iron 5-15 g / l, and acid 3-15 g / l. The operating temperature is 70-75°C, the operating time is 30-40 min, and the amount of iron powder added is 1.0-1.2 times the theoretical amount. The copper content of the solution after copper precipitation is controlled to be 100-150 mg / l (reserved for impurity removal in the subsequent process). The output copper slag contains copper greater than 60% and iron less than 1%, and the direct copper recovery rate is greater than 85%.

[0025] The concentrated supernatant of the first-stage oxygen pressure leaching solution contains more than 1200 mg / l of chlorine, 5-15 g / l of iron, more than 1000 mg / l of copper, and 3-15 g / l of acid. The operating temperature is 70-75°C, the operating time is 30-40 minutes, and fresh copper slag (new quality copper slag) is added to produce a dechlorinated liquid with a chlorine content of less than 200 mg / l.

[0026] 5) The operating conditions of the present invention are optimized as follows: a. The optimal dechlorination acidity is around pH 1.5, but this method can dechlorinate at low acid levels of 3-5 g / l, medium acid levels of 10-15 g / l, and high acid levels of 20-45 g / l. The dechlorination efficiency is 85-90% at around pH 1.5, and gradually decreases when the pH is below 1.5, reaching 80-85% at 5-10 g / l, 70-80% at 10-20 g / l, and 60-70% at 20-45 g / l. The dechlorination efficiency gradually decreases when the pH is above 1.5, reaching 60-70% at pH 2.0-3.0 and 45-60% at pH 3.0-4.5.

[0027] b. When the acid content of the concentrated supernatant of the first oxygen pressure leaching solution is low, waste electrolytic solution is added to the No. 1 copper precipitation tank for adjustment; when the acid content is high, neutralizing agent is added to the No. 1 copper precipitation tank for adjustment.

[0028] 6) This invention reduces corrosion of system equipment, facilities, and pipelines. The higher the chloride ion concentration, the greater the conductivity of the aqueous solution, the lower the resistance of the electrolyte, and the easier it is for chloride ions to reach the metal surface, accelerating the progression of localized corrosion. Particularly in acidic environments, chloride ions form a chloride salt layer on the metal surface, replacing the protective iron carbonate film, leading to pitting, stress corrosion, pitting, and crevice corrosion. During the corrosion process, chloride ions accumulate not only in the pitting area but also in the surrounding area, representing the initial stage of corrosion formation.

[0029] At the source of the main process of oxygen pressure leaching, new copper slag is used to remove Cl in the solution. - Reducing the concentration from 600-1800mg / l to below 200mg / l before sending it to the downstream process will greatly reduce the corrosion of system equipment and facilities and pipelines, and extend the service life of stainless steel pipelines, pumps and valves from 3 months to 9-12 months.

[0030] 7) The present invention can extend the service life of the lead anode plate of the store. During the electrolytic process, chloride ions are oxidized into chlorine gas at the anode, which will corrode the lead anode.

[0031] Lead plates are plated before being used in electrolysis to form a layer of PbO2 film on the surface of the plate. It is not as dense as the aluminum passivation film, and there are still some tiny pores on the film. Chloride ions with a small degree of hydration have a very small radius and can easily penetrate into the protective film through these pores and react with lead. The reaction equation is:

[0032] The resulting PbCl2 has a much higher solubility than PbSO4. At 25°C, the solubility of PbCl2 is 10.786 g / L, while the solubility of PbSO4 is 0.0452 g / L. Therefore, PbCl2 converts to PbSO4, precipitating as a solid phase. This releases chloride ions, which can interact with the lead anode again, continuously corroding the anode plate. The resulting solid PbSO4 particles are incorporated into the electrolytic zinc, reducing the quality of the zinc product.

[0033] At the source of the main process of oxygen pressure leaching, new copper slag is used to remove Cl in the solution. - The concentration is reduced from 600-1800 mg / l to below 200 mg / l before being sent to the electrowinning workshop. This greatly reduces the corrosion of lead anodes by chloride ions during the electrowinning process, improves the operating environment of the electrowinning workshop, and ensures the health of workers.

[0034] The zinc electrolysis process uses aluminum plates as cathode plates. A corrosion-resistant oxide film, also known as a passivation film, forms on the aluminum plate's surface. This film's primary components are Al2O3 and Al(OH)3. The passivation film on the aluminum surface forms quickly, is thick, and is very dense and complete, firmly bonding to the metal, making it suitable for use as a cathode plate in acidic solutions. During electrolysis, metallic zinc is deposited on this passivation film. Because its structure differs significantly from the crystal structure of the electrolytic zinc, the bond between the two is weak and easily peels off.

[0035] When chloride ions are present in the acidic zinc sulfate electrolyte, the chloride ions react with O2 - OH - The repulsion and replacement effect reacts with the passivation film on the surface of the aluminum plate to generate AlCl3 and [AlCl6] 3- Ions enter the solution, the passivation film is corroded, and the reaction that occurs is:

[0036] The passivation film is destroyed, the electrolyte contacts the aluminum plate and causes corrosion of the aluminum plate. The zinc deposited on the plate is not easy to peel off, thus affecting the 0 # The quality of zinc products is affected, and the plates need to be replaced frequently, which increases production costs and reduces production efficiency.

[0037] Therefore, chlorine in zinc sulfate electrolytes accelerates electrode corrosion, shortening electrode life, making stripping of electrolytically deposited zinc difficult, and increasing the lead content in the product, leading to higher production costs, lower product quality, and reduced production efficiency. When the chloride ion content in the electrolyte exceeds 0.5g / L, electrode plate corrosion accelerates, seriously affecting the quality of zinc products. Reducing the chlorine content in the electrolyte can reduce electrode plate consumption, improve product quality, reduce corrosion of equipment and pipelines, and increase production efficiency.

[0038] The beneficial effects of the present invention are as follows: 1) The present invention adopts a one-step copper deposition and chlorine removal process at the source of the main process of oxygen pressure leaching; 2) The present invention solves the shortcomings of poor copper slag dechlorination effect, low copper slag utilization rate, and easy deactivation of copper slag; 3) The present invention solves the problem of inability to circulate dechlorination in the system; 4) The present invention shortens the process flow, reduces losses, and efficiently recovers copper and removes chlorine; 5) The present invention reduces corrosion of system equipment, facilities and pipelines; 6) The present invention produces a new solution with low chlorine content, which prolongs the service life of the electrolytic anode plate and ensures the quality of the 0# zinc product; 7) The present invention replaces the traditional waste liquid dechlorination process, achieving the purpose of reducing investment costs and saving production and operation costs.

[0039] 8) The present invention realizes the new copper slag containing 65%-70% of elemental copper, and the Cl content in the new solution - The concentration is below 200mg / l.

[0040] 9) The present invention achieves the goals of simple operation, environmental protection, energy saving, and good economic benefits; BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0042] The present invention is further described below with reference to the embodiments, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention fall within the scope of protection of the present invention.

[0043] The method for recovering copper from oxygen pressure leaching solution by cyclic dechlorination of the present invention comprises pre-treatment, dechlorination, replacement and post-treatment steps, specifically including: A. Pretreatment: Clarify and separate the oxygen pressure leaching liquid to obtain the material supernatant a; B. Dechlorination: Add fresh copper slag as a dechlorinating agent to material a and perform dechlorination reaction at 70-75°C for 30-40 minutes to obtain cuprous chloride precipitate b and dechlorinated slurry c; The fresh copper slag is fresh copper slag in which the elemental copper contained in the copper slag has not been oxidized by air; C. Replacement: adding a replacement agent to the dechlorinated slurry c to replace the copper slurry to obtain copper slurry d; D. Post-processing: 1) The copper slurry d is settled in a settling tank to obtain a supernatant e and an underflow f; 2) A portion of the bottom flow f after sedimentation is pumped to the dechlorination step for circulation; 3) A portion of the underflow is pumped into the filter press, and after filtration, the material copper slag g is obtained, and the filtrate is sent to the main process.

[0044] The chloride ion concentration in the oxygen pressure leaching solution is 600-1800 mg / L.

[0045] The new copper slag described in step B is the copper-cadmium slag produced in the hydrometallurgical zinc purification section, the active copper produced by zinc powder reducing copper sulfate, or the cuprous oxide dechlorination agent.

[0046] The displacing agent described in step C is iron powder.

[0047] D. The sedimentation in the sedimentation tank described in step 1) is to use natural sedimentation to perform liquid-solid separation, that is, the liquid-solid separation effect is achieved by utilizing the gravity principle of the copper slurry d to achieve natural sedimentation for 40 to 60 minutes.

[0048] The present invention will be further described below with reference to specific implementation cases: Example 1

[0049] The supernatant after the concentrated oxygen pressure leaching with a chloride ion concentration of 680.36 mg / L is continuously fed into the 1# copper precipitation tank. During the stirring process, the copper-cadmium slag produced by the wet zinc smelting purification section is added with a dechlorination agent for dechlorination to obtain a dechlorinated slurry containing 103.21 mg / L of chlorine. Then (from the outlet of the 1# copper precipitation tank) it flows to the 2# copper precipitation tank by gravity. During the stirring process, iron powder is continuously added to precipitate copper. During this period, the copper content of the solution in the 2# copper precipitation tank is sampled and analyzed. The copper ion content of the solution is controlled at 0.096 g / L (for purification and impurity removal in the later process) to obtain a copper precipitation slurry. The copper precipitation slurry is gravity-flowed (or pumped) to the sedimentation tank for Liquid-solid separation, the supernatant of the sedimentation tank overflows into the supernatant storage tank (providing solution for subsequent work sections); 10% of the bottom flow after sedimentation (new copper slag) is pumped to the 1# copper precipitation tank for circulating dechlorination, and 90% of the bottom flow after sedimentation is pumped to the copper slag for a first filtration to obtain new copper slag and copper-removing filtrate. The copper-removing filtrate is pumped into the supernatant storage tank (providing solution for subsequent work sections), and the new copper slag is slurried and washed with production water or weak acid washing water. The washing slurry is pumped to the copper slag for secondary filtration. After filtration, copper slag containing 78.3% copper and washing liquid are obtained. The copper slag here is directly exported as a product, and the washing liquid is returned to the main process or used as slurry liquid. Example 2

[0050] The supernatant after concentrated oxygen pressure leaching with a chloride ion concentration of 1183.97 mg / L is continuously fed into the 1# copper precipitation tank. During the stirring process, zinc powder is added to reduce the active copper produced by copper sulfate for dechlorination to obtain a dechlorinated slurry containing 168.33 mg / L of chlorine. Then (from the outlet of the 1# copper precipitation tank) it flows to the 2# copper precipitation tank by gravity. During the stirring process, iron powder is continuously added to precipitate copper. During this period, the copper content of the solution in the 2# copper precipitation tank is sampled and analyzed. The copper ion content of the solution is controlled at 0.067 g / L (for purification and impurity removal in the later process) to obtain a copper precipitation slurry. The copper precipitation slurry is gravity-flowed (or pumped) to the sedimentation tank for liquid-solid separation. After separation, the supernatant of the sedimentation tank overflows into the supernatant storage tank (providing solution for subsequent work sections); 30% of the bottom flow (new copper slag) after sedimentation is pumped to the 1# copper precipitation tank for circulating dechlorination, and 70% of the bottom flow after sedimentation is pumped to the copper slag for a first filtration to obtain new copper slag and copper-removing filtrate. The copper-removing filtrate is pumped into the supernatant storage tank (providing solution for subsequent work sections), and the new copper slag is slurried and washed with production water or weak acid washing water. The washing slurry is pumped to the copper slag for secondary filtration. After filtration, copper slag containing 69.78% copper and washing liquid are obtained. The copper slag here is directly exported as a product, and the washing liquid is returned to the main process or used as slurry. Example 3

[0051] The supernatant after concentrated oxygen pressure leaching with a chloride ion concentration of 936.58 mg / L is continuously fed into the 1# copper precipitation tank. During the stirring process, cuprous oxide dechlorinator is added for dechlorination to obtain a dechlorinated slurry containing 133.88 mg / L of chlorine. Then (from the outlet of the 1# copper precipitation tank) it flows to the 2# copper precipitation tank by gravity and is stirred. During the stirring process, iron powder is continuously added to precipitate copper. During this period, the copper content of the solution in the 2# copper precipitation tank is sampled and analyzed. The copper ion content of the solution is controlled at 0.088 g / L (for purification and impurity removal in the later process) to obtain a copper precipitation slurry. The copper precipitation slurry is gravity-flowed (or pumped) to the sedimentation tank for liquid-solid separation. The supernatant of the sedimentation tank overflows into the supernatant storage tank (providing solution for subsequent work sections); 20% of the bottom flow (new copper slag) after sedimentation is pumped to the 1# copper precipitation tank for circulating dechlorination, and 80% of the bottom flow after sedimentation is pumped to the copper slag for a first filtration to obtain new copper slag and copper-removing filtrate. The copper-removing filtrate is pumped into the supernatant storage tank (providing solution for subsequent work sections), and the new copper slag is slurried and washed with production water or weak acid washing water. The washing slurry is pumped to the copper slag for secondary filtration. After filtration, copper slag containing 73.44% copper and washing liquid are obtained. The copper slag here is directly exported as a product, and the washing liquid is returned to the main process or used as slurry. Example 4

[0052] The supernatant after the concentrated oxygen pressure leaching with a chloride ion concentration of 768.47 mg / L is continuously fed into the 1# copper precipitation tank. During the stirring process, the copper-cadmium slag produced by the wet zinc smelting purification section is added with a dechlorination agent for dechlorination to obtain a dechlorinated slurry containing 113.83 mg / L of chlorine. Then (from the outlet of the 1# copper precipitation tank) it flows to the 2# copper precipitation tank by gravity and is stirred. During the stirring process, iron powder is continuously added to precipitate copper. During this period, the copper content of the solution in the 2# copper precipitation tank is sampled and analyzed. The copper ion content of the solution is controlled at 0.072 g / L (for purification and impurity removal in the later process) to obtain a copper precipitation slurry. The copper precipitation slurry is gravity-flowed (or pumped) to the sedimentation tank for Liquid-solid separation is carried out, and the supernatant of the sedimentation tank overflows into the supernatant storage tank (providing solution for subsequent work sections); 25% of the bottom flow (new copper slag) after sedimentation is pumped to the 1# copper precipitation tank for circulating dechlorination, and 75% of the bottom flow after sedimentation is pumped to the copper slag for a first filtration to obtain new copper slag and copper-removing filtrate. The copper-removing filtrate is pumped into the supernatant storage tank (providing solution for subsequent work sections), and the new copper slag is slurried and washed with production water or weak acid washing water. The washing slurry is pumped to the copper slag for secondary filtration. After filtration, copper slag containing 72.33% copper and washing liquid are obtained. The copper slag here is directly exported as a product, and the washing liquid is returned to the main process or used as slurry liquid.

Claims

1. A method for recycling and dechlorinating copper by oxygen pressure leaching solution, characterized in that: The method for recycling copper from oxygen pressure leaching solution and dechlorination includes pre-treatment, dechlorination, replacement and post-treatment steps, specifically including: A. Pretreatment: Clarify and separate the oxygen pressure leaching liquid to obtain the material supernatant a; B. Dechlorination: Add fresh copper slag as a dechlorinating agent to material a and perform dechlorination reaction at 70-75°C for 30-40 minutes to obtain cuprous chloride precipitate b and dechlorinated slurry c; The fresh copper slag is fresh copper slag in which the elemental copper contained in the copper slag has not been oxidized by air; C. Replacement: adding a replacement agent to the dechlorinated slurry c to replace the copper slurry to obtain copper slurry d; D. Post-processing: 1) The copper slurry d is settled in a settling tank to obtain a supernatant e and an underflow f; 2) A portion of the bottom flow f after sedimentation is pumped to the dechlorination step for circulation; 3) A portion of the underflow is pumped into the filter press, and after filtration, the material copper slag g is obtained, and the filtrate is sent to the main process.

2. The method for recycling copper from oxygen pressure leaching solution according to claim 1, wherein: The chloride ion concentration in the oxygen pressure leaching solution is 600-1800 mg / L.

3. The method for recycling copper by oxygen pressure leaching solution according to claim 1, wherein: The new copper slag described in step B is the copper-cadmium slag produced in the hydrometallurgical zinc purification section, the active copper produced by zinc powder reducing copper sulfate, or the cuprous oxide dechlorination agent.

4. The method for recycling copper from oxygen pressure leaching solution according to claim 1, wherein: The displacing agent described in step C is iron powder.

5. The method for recycling copper from oxygen pressure leaching solution according to claim 1, wherein: D. The sedimentation in the sedimentation tank described in step 1) is to use natural sedimentation to perform liquid-solid separation, that is, the liquid-solid separation effect is achieved by utilizing the gravity principle of the copper slurry d to achieve natural sedimentation for 40 to 60 minutes.

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