Method for recovering silver, selenium, tellurium and copper from copper separation liquid

Abstract

The invention relates to the technical field of smelting, and discloses a method for recovering silver, selenium, tellurium and copper from copper separation liquid, which comprises the following steps: carrying out acid leaching reaction on roasting slag to obtain the copper separation liquid; reducing the copper separation liquid by using hydrochloric acid, an alkaline medium and formaldehyde to obtain solid silver, and obtaining silver reduced liquid; sulfur dioxide and / or sodium sulfite are / is used for reducing the silver-deposited liquid to obtain mixed selenium and tellurium slag, and selenium and tellurium deposited liquid is obtained; adding sodium sulfite into the mixed selenium-tellurium slag to leach selenium to obtain selenium leaching liquid and tellurium slag, and adding sulfuric acid into the selenium leaching liquid to obtain crude selenium; the method comprises the following steps: performing chlorination reaction on tellurium residues to obtain tellurium leaching liquid and tellurium residues, adding sodium sulfide or / and sodium hydrosulfide into the tellurium leaching liquid to perform vulcanization and impurity removal, and removing heavy metal impurities in the tellurium leaching liquid to obtain vulcanized liquid and vulcanized residues; reducing the vulcanized liquid by using sulfur dioxide to obtain tellurium powder and tellurium precipitation liquid; and the tellurium precipitation liquid meeting the preset standard is subjected to electrodeposition decoppering through a liquid purification system, and electrodeposited copper and secondary decoppering final liquid are produced.

Description

Technical Field

[0001] The present invention relates to the technical field of smelting, and in particular to a method for recovering silver, selenium, tellurium, and copper from copper separation solution. Background Art

[0002] In the related art, the roasting slag of anode slime is roasted in a rotary kiln, and after acid leaching and copper separation, copper separation solution is obtained. In some other technologies, iron powder is added to recover sponge copper, and the remaining selenium and tellurium are sent to sewage treatment together with waste acid; by means of evaporation and concentration, copper sulfate is prepared. Not only is the energy consumption large, but the market price of the prepared copper sulfate is not good, and it can only be sent back for smelting treatment; by adding basic sodium carbonate salt for neutralization, basic copper carbonate is prepared for sale, generating a large amount of waste water and having poor environmental protection effect.

[0003] The above technologies have losses of valuable metals, reducing the recovery rates of silver and tellurium. At the same time, the contents of selenium, tellurium, chlorine, and particulate matter in the copper separation solution entering the electrowinning system are not controlled, which will affect the product quality and production efficiency of electrolytic cathode copper. With the gradual increase of metal prices and environmental protection standards, there is an urgent need for a copper separation solution treatment technology that is environmentally friendly and comprehensively recovers valuable metals. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this purpose, the object of the present invention is to provide a method for recovering silver, selenium, tellurium, and copper from copper separation solution, which can effectively recover valuable metals such as silver and tellurium, improve the direct recovery rate and recovery rate of silver, selenium, and tellurium, control the contents of selenium, tellurium, chlorine, and particulate matter in the electrolytic purified solution system, improve the product quality and production efficiency of electrolytic cathode copper, reduce the external discharge amount of waste water, and enhance the environmental protection governance ability.

[0005] To achieve the above object, an embodiment of the present invention provides a method for recovering silver, selenium, tellurium, and copper from copper separating solution, comprising: performing an acid leaching reaction on roasted slag to obtain copper separating solution; wherein, the copper separating solution contains liquid copper sulfate, liquid nickel sulfate, liquid silver sulfate, liquid selenous acid, and liquid tellurous acid; reducing solid silver from the copper separating solution by using hydrochloric acid, basic medium, and formaldehyde, and obtaining a solution after silver reduction; reducing a mixed selenium-tellurium slag from the solution after silver precipitation by using sulfur dioxide and / or sodium sulfite, and obtaining a solution after selenium and tellurium precipitation; wherein, the solution after silver precipitation contains liquid selenous acid and liquid tellurous acid; adding sodium sulfite to the mixed selenium-tellurium slag to leach selenium, obtaining a selenium leaching solution and tellurium slag, adding sulfuric acid to the selenium leaching solution to obtain crude selenium; performing a chlorination reaction on the tellurium slag to obtain a tellurium leaching solution and tellurium slag, adding sodium sulfide and / or sodium hydrosulfide to the tellurium leaching solution for sulfurization to remove heavy metal impurities in the tellurium leaching solution, obtaining a solution after sulfurization and a sulfurized slag; wherein, the solution after sulfurization contains liquid tellurous acid; reducing tellurium powder and a solution after tellurium precipitation from the solution after sulfurization by using sulfur dioxide; subjecting the solution after tellurium precipitation meeting a preset standard to electrowinning copper removal through a purification system, producing electrowon copper and a final solution after secondary copper removal; wherein, the final solution after secondary copper removal contains sulfuric acid.

[0006] In addition, the method for recovering silver, selenium, tellurium, and copper from copper separating solution according to the above embodiment of the present invention may further have the following additional technical features:

[0007] According to some embodiments of the present invention, it further includes using the final solution after secondary copper removal to perform acid leaching on the roasted slag.

[0008] According to some embodiments of the present invention, the roasted slag mainly includes solid copper sulfate, solid nickel sulfate, solid silver sulfate, solid selenium dioxide, solid tellurium dioxide, lead sulfate, etc.; performing an acid leaching reaction on the roasted slag to obtain copper separating solution; wherein, the copper separating solution mainly contains liquid copper sulfate, liquid nickel sulfate, liquid silver sulfate, liquid selenous acid, and liquid tellurous acid, including: controlling the selenium content in the roasted slag to be less than 0.1%, the sulfuric acid concentration used in the acid leaching reaction is 80 - 120 g / L, the liquid-solid ratio of sulfuric acid to roasted slag is 4:1, the reaction temperature is 70 - 90 °C, and the reaction time is 4 - 5 h.

[0009] According to some embodiments of the present invention, reducing solid silver from the copper separating solution by using hydrochloric acid, basic medium, and formaldehyde, and obtaining a solution after silver reduction, includes: slowly adding a hydrochloric acid solution to precipitate silver ions according to the silver concentration in the copper separating solution, sampling and dropping hydrochloric acid until no white silver chloride precipitates as the reaction end point; continuing to add sodium hydroxide to the silver chloride according to a liquid-solid ratio of 2 - 5:1 to adjust the pH value ≥ 11, the reaction temperature is normal temperature, slowly dropping formaldehyde until no silver powder is produced as the reaction end point, and the reduction time is 2 - 4 h.

[0010] According to some embodiments of the present invention, sulfur dioxide and / or sodium sulfite are used to reduce a mixed selenium-tellurium residue from the post-silver precipitation solution, and a post-selenium-tellurium precipitation solution is obtained, including: adding sulfur dioxide or sodium sulfite to the post-silver precipitation solution, with a reduction reaction time of 2-5 h and a reaction temperature of 80-95 °C.

[0011] According to some embodiments of the present invention, sodium sulfite is added to the mixed selenium-tellurium residue to leach selenium, obtaining a selenium leaching solution and a tellurium residue, and sulfuric acid is added to the selenium leaching solution to obtain crude selenium, including: adding sodium sulfite to the filtered mixed selenium-tellurium residue to leach selenium, with a liquid-solid ratio of 4:1, reacting at room temperature, and the molar excess coefficient of sodium sulfite to selenium being 2-5 times, and the reaction time being 3-5 h.

[0012] According to some embodiments of the present invention, the tellurium residue is subjected to a chlorination reaction to obtain a tellurium leaching solution and a tellurium residue, and sodium sulfide or / and sodium hydrosulfide are added to the tellurium leaching solution for sulfurization and impurity removal to remove heavy metal impurities in the tellurium leaching solution, obtaining a post-sulfurization solution and a sulfurization residue, including: subjecting the tellurium residue to a chlorination reaction, with a liquid-solid ratio of 5:1, a reaction temperature of 80-95 °C, a reaction time of 3-4 h, adding chlorine or sodium chlorate and hydrochloric acid, and tellurium enters the solution in the form of tellurous acid and the remaining heavy metal impurities enter the solution in the form of chlorides; wherein, the molar ratio of tellurium to sodium chlorate is 1:2-5; after the tellurium residue is completely dissolved and cooled to room temperature, sodium sulfide or sodium hydrosulfide is added to remove heavy metal impurities in the solution.

[0013] According to some embodiments of the present invention, tellurium powder and a post-tellurium precipitation solution are obtained by reducing the post-sulfurization solution with sulfur dioxide, including: reducing the filtered post-sulfurization solution with sulfur dioxide to obtain tellurium powder, with a reaction temperature of 85-95 °C and a reaction time of 2-4 h.

[0014] According to some embodiments of the present invention, the post-tellurium precipitation solution meeting the preset standard is subjected to electrowinning for copper removal through a purification system, producing electrowon copper and a secondary post-copper-removal solution, including subjecting the post-tellurium precipitation solution with detected selenium and tellurium < 0.05 g / L and chloride ions < 0.1 g / L to precision filtration to remove fine particles larger than 1 μm in the solution, entering the purification system for electrowinning copper removal, mixing the copper separation solution and the first-stage electrolysis solution in a preset ratio, controlling the copper ion concentration to be lower than 25 g / L, and controlling the current density at 250-300 A / m 3 , and flowing into the electrowinning cell at a flow rate of 40-60 L / min for copper electrowinning, and electrowon copper is obtained at the cathode.

[0015] A method for recovering silver, selenium, tellurium and copper from copper separating solution according to an embodiment of the present invention includes: performing an acid leaching reaction on roasting slag to obtain copper separating solution; wherein, the copper separating solution contains liquid copper sulfate, liquid nickel sulfate, liquid silver sulfate, liquid selenous acid and liquid tellurous acid; reducing solid silver from the copper separating solution by using hydrochloric acid, an alkaline medium and formaldehyde, and obtaining a solution after silver reduction; reducing a mixed selenium-tellurium slag from the solution after silver precipitation by using sulfur dioxide and / or sodium sulfite, and obtaining a solution after selenium and tellurium precipitation; wherein, the solution after silver precipitation contains liquid selenous acid and liquid tellurous acid; adding sodium sulfite to the mixed selenium-tellurium slag to leach selenium, obtaining a selenium leaching solution and tellurium slag, adding sulfuric acid to the selenium leaching solution to obtain crude selenium; performing a chlorination reaction on the tellurium slag to obtain a tellurium leaching solution and tellurium slag, adding sodium sulfide and / or sodium hydrosulfide to the tellurium leaching solution for sulfurization impurity removal to remove heavy metal impurities in the tellurium leaching solution, obtaining a solution after sulfurization and a sulfurized slag; wherein, the solution after sulfurization contains liquid tellurous acid; reducing tellurium powder and a solution after tellurium precipitation from the solution after sulfurization by using sulfur dioxide; subjecting the solution after tellurium precipitation meeting a preset standard to electrowinning copper removal through a purification system, producing electrowon copper and a final solution after secondary copper removal; wherein, the final solution after secondary copper removal contains sulfuric acid. Thus, this method can effectively recover valuable metals such as silver and tellurium, improve the direct recovery rate and recovery rate of silver, selenium and tellurium, control the contents of selenium, tellurium, chlorine and particulate matters entering the electrolytic purification system, improve the product quality and production efficiency of electrolytic cathode copper, reduce the external discharge amount of wastewater, and enhance the environmental protection governance ability.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a method for recovering silver, selenium, tellurium and copper from copper separating solution according to some embodiments of the present invention. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0019] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should have the ordinary meanings understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar terms used in the embodiments of the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to represent relative position relationships, and when the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0020] As described in the background art section, the calcined slag of anode slime roasted in a rotary kiln is acid-leached to separate copper, and a copper-separating solution is obtained. In some other technologies, the method of adding iron powder to recover sponge copper is adopted, and the remaining selenium and tellurium are sent to sewage treatment together with the waste acid; the method of evaporation and concentration is adopted to prepare copper sulfate, which not only consumes a large amount of energy, but also the market price of the prepared copper sulfate is not good, and it can only be sent back for smelting treatment; by adding basic sodium carbonate salt for neutralization, basic copper carbonate is prepared for sale, generating a large amount of wastewater and having a poor environmental protection effect.

[0021] The applicant found in the process of implementing the present invention that the above technologies have losses of valuable metals, reducing the recovery rates of silver and tellurium. At the same time, the contents of selenium, tellurium, chlorine and particulate matter in the copper-separating solution entering the electrowinning system are not controlled, which will all affect the product quality and production efficiency of electrolytic cathode copper. With the gradual increase of metal prices and environmental protection standards, there is an urgent need for a copper-separating solution treatment technology that is environmentally friendly and comprehensively recovers valuable metals.

[0022] Therefore, the present invention can effectively recover valuable metals such as silver and tellurium, improve the direct recovery rate and recovery rate of silver, selenium and tellurium, control the contents of selenium, tellurium, chlorine and particulate matter in the electrolytic purified solution system, improve the product quality and production efficiency of electrolytic cathode copper, reduce the external discharge amount of wastewater, and enhance the environmental protection governance ability.

[0023] The method for recovering silver, selenium, tellurium and copper from a copper-separating solution proposed in the embodiments of the present invention will be described below with reference to the accompanying drawings.

[0024] Refer to Figure 1 , which is a schematic diagram of a method for recovering silver, selenium, tellurium and copper from a copper-separating solution according to some embodiments of the present invention.

[0025] In the process flow of treating copper anode slime by the wet process, first, the copper anode slime is slurried with concentrated sulfuric acid, and then the mixture of the slurried copper anode slime and concentrated sulfuric acid is roasted to obtain roasted slag. Finally, the roasted slag is subjected to acid leaching reaction so that most of the solid copper, part of the solid silver, solid selenium, and solid tellurium in the roasted slag are dissolved into a liquid state, and the copper and part of the impurities are leached into the solution to form a copper separation solution.

[0026] Specifically, it can be represented by the following chemical equations:

[0027] CuSO 4 (s) = CuSO 4 (l)

[0028] NiSO 4 (s) = NiSO 4 (l)

[0029] Ag 2 SO 4 (s) = Ag 2 SO 4 (l);

[0030] SeO 2 (s) + H 2 O(l) = H 2 SeO 3 (l)

[0031] TeO 2 (s) + H 2 O(l) = H 2 TeO 3 (l)

[0032] Among them, (·) represents the state of the substance, (s) represents the solid state, and (l) represents the liquid state. The roasted slag contains solid copper sulfate (CuSO 4 (s)), solid nickel sulfate (NiSO 4 (s)), solid silver sulfate (Ag 2 SO 4 (s)), solid selenium dioxide (SeO 2 (s)), and solid tellurium dioxide (TeO 2 (s)). The copper separation solution contains liquid copper sulfate (CuSO 4 (l)), liquid nickel sulfate (NiSO 4 (l)), liquid silver sulfate (Ag 2 SO 4 (l)), liquid selenous acid (H 2 SeO 3 (l)), liquid tellurous acid (H 2 TeO 3(l)) and liquid water (H 2 O(l)).

[0033] Among them, the wet process refers to the process of treating materials with liquid chemical reagents, usually involving steps such as cleaning, etching, and stripping, in order to remove contaminants, form specific structures, or remove unwanted materials. Pulverization refers to the process of dispersing, dissolving, and mixing raw materials to make them into a slurry that is easy to process subsequently. The pulverization process usually involves mixing solid particles with a liquid and making them uniformly dispersed through mechanical stirring or chemical reactions to form a slurry with certain fluidity and stability. Roasting is a heat treatment process, usually used for the pretreatment of ores, metal compounds, or chemical raw materials. By roasting at high temperatures, moisture and volatile components in the raw materials can be removed, certain compounds can be decomposed, or chemical reactions can occur in the raw materials, thereby improving their physical and chemical properties and facilitating subsequent processing or extraction.

[0034] After obtaining the copper-dividing solution, liquid hydrochloric acid (HCl(l)) is added to the copper-dividing solution to precipitate silver ions, thereby generating solid silver chloride (AgCl(s)). An alkaline medium is added to the solid silver chloride. Under alkaline conditions, the solid silver chloride can be reduced with liquid formaldehyde (HCHO(l)) to obtain solid silver (Ag(s)), and a silver-reduced solution is obtained. Among them, the solid silver can be silver powder, and the silver-reduced solution is recycled by the system after treatment.

[0035] Specifically, it can be represented by the following chemical equations:

[0036] Ag 2 SO 4 (l) + 2HCl(l) = 2AgCl(s) + H 2 SO 4 (l)

[0037] 2AgCl(s) + 2NaOH(l) = Ag 2 O(s) + 2NaCl(l) + H 2 O(l)

[0038] Ag 2 O(s) + HCHO(l) = 2Ag(s) + HCOOH(l)

[0039] Among them, the alkaline medium is liquid sodium hydroxide (NaOH(l)).

[0040] After obtaining the silver-precipitated solution, gaseous sulfur dioxide and / or liquid sodium sulfite are added to the silver-precipitated solution to obtain a mixed selenium-tellurium residue by reduction from the silver-precipitated solution, and a selenium- and tellurium-precipitated solution is obtained. The silver-precipitated solution contains liquid selenous acid (H 2 SeO 3 (l)) and liquid tellurous acid (H2 TeO 3 (l))。

[0041] Specifically, it can be represented by the following chemical equation:

[0042] H 2 TeO 3 (l) + 2SO 2 (g) + H 2 O(l) = Te(s) + 2H 2 SO 4 (l)

[0043] H 2 SeO 3 (l) + 2SO 2 (g) + H 2 O(l) = Se(s) + 2H 2 SO 4 (l)

[0044] H 2 TeO 3 (l) + 2Na 2 SO 3 (l) = Te(s) + 2Na 2 SO 4 (l) + H 2 O(l)

[0045] H 2 SeO 3 (l) + 2Na 2 SO 3 (l) = Se(s) + 2Na 2 SO 4 (l) + H 2 O(l)

[0046] Among them, (g) represents gaseous state. The mixed selenium-tellurium residue contains solid tellurium (Te(s)) and solid selenium (Se(s)). When gaseous sulfur dioxide is added to the post-silver precipitation solution, the post-selenium-tellurium precipitation solution contains liquid sulfuric acid (H 2 SO 4 (l)); when liquid sodium sulfite is added to the post-silver precipitation solution, the post-selenium-tellurium precipitation solution contains liquid sodium sulfate (Na 2 SO 4 (l)) and liquid water (H 2 O(l)).

[0047] After obtaining the mixed selenium-tellurium residue, filter the mixed selenium-tellurium residue, and add liquid sodium sulfite (Na 2 SO 3(l)) Leach selenium to obtain a selenium leaching solution and tellurium residue. Add liquid sulfuric acid to the selenium leaching solution for reduction to obtain crude selenium.

[0048] Specifically, it can be represented by the following chemical equations:

[0049] Se(s) + Na 2 SO 3 (l) = Na 2 SeSO 3 (l)

[0050] Na 2 SeSO 3 (l) + H 2 SO 4 (l) = Na 2 SO 4 (l) + Se(s) + SO 2 (g) + H 2 O(l)

[0051] Among them, the selenium leaching solution contains sodium selenosulfate (Na 2 SeSO 3 (l)).

[0052] After obtaining the tellurium residue, filter the tellurium residue. Add gaseous chlorine (Cl 2 (g)) to the filtered tellurium residue for chlorination reaction of the tellurium residue to obtain a tellurium leaching solution and tellurium residue. Add liquid sodium sulfide (Na 2 S) or / and sodium hydrosulfide to the tellurium leaching solution for sulfurization and impurity removal to remove heavy metal impurities in the tellurium leaching solution to obtain a sulfurized solution and sulfurized residue. Among them, the tellurium residue and sulfurized residue contain impurities such as copper, lead, arsenic, antimony, and bismuth. Return the tellurium residue and sulfurized residue to the copper smelting system.

[0053] Specifically, it can be represented by the following chemical equations:

[0054] Te(s) + 3H 2 O(l) + 2Cl 2 (g) = H 2 TeO 3 (l) + 4HCl(l)

[0055] Me(s) + 2HCl(l) = MeCl 2 (l) + H 2 (g)

[0056] MeCl 2 (l) + Na 2 S(l) = MeS(s) + 2NaCl(l)

[0057] Among them, the tellurium leaching solution contains liquid tellurous acid (H2 TeO 3 (l)), liquid hydrochloric acid (HCl(l)), liquid dichloromethane (MeCl 2 (l)) and liquid sodium chloride (NaCl(l)). The post-sulfidation solution contains tellurous acid in liquid form.

[0058] After obtaining the post-sulfidation solution, the post-sulfidation solution is filtered. Gaseous sulfur dioxide is added to the filtered post-sulfidation solution to reduce tellurium powder and the post-tellurium precipitation solution from the post-sulfidation solution. The wastewater of the solution after tellurium powder reduction is recycled after treatment.

[0059] Specifically, it can be represented by the following chemical equation:

[0060] H 2 TeO 3 (l) + 2SO 2 (g) + H 2 O(l) = Te(s) + 2H 2 SO 4 (l)

[0061] Among them, the post-tellurium precipitation solution contains liquid copper sulfate (CuSO 4 (l)) and liquid water (H 2 O(l)).

[0062] After obtaining the post-tellurium precipitation solution, the contents of selenium, tellurium, chloride ions, and particulate matter in the post-tellurium precipitation solution are detected. The post-tellurium precipitation solution with the contents of selenium, tellurium, chloride ions, and particulate matter lower than the control concentration is precisely filtered to remove the fine particulate matter in the post-tellurium precipitation solution. Then, the post-tellurium precipitation solution meeting the preset standard is subjected to electrowinning copper removal through a purification liquid system to produce electrowon copper and the final solution after secondary copper removal. The increased acid in the copper electrolysis system is returned to the acid leaching and copper separation process as supplementary acid.

[0063] Specifically, it can be represented by the following chemical equation:

[0064] CuSO 4 (l) + H 2 O(l) = Cu(s) + H 2 SO 4 (l) + 1 / 2O 2 (g)

[0065] Among them, the final solution after secondary copper removal contains liquid sulfuric acid (H 2 SO 4 (l)).

[0066] After obtaining the final solution of secondary copper removal, the roasted slag is acid-leached with the final solution of secondary copper removal. Since the increased acid generated after secondary copper removal is returned to the copper separation process of acid leaching, recycling the waste acid not only reduces the consumption of sulfuric acid but also solves the acid balance problem in the electrolysis plant. After the waste water in the process flow recovers valuable metals, it reduces environmental pollution and realizes the sustainable utilization of resources.

[0067] As a specific embodiment, the liquid-solid ratio is 4:1, the sulfuric acid concentration is 80 - 120 g / l, the reaction temperature is 70 - 90 °C, and the acid leaching time is 4 - 5 h; more than 98% of copper, nickel, about 30% of silver, selenium, and tellurium dissolve into the copper separation solution.

[0068] Specifically, it can be represented by the following chemical equations:

[0069] CuSO 4 (s)=CuSO 4 (l)

[0070] NiSO 4 (s)=NiSO 4 (l)

[0071] Ag 2 SO 4 (s)=Ag 2 SO 4 (l);

[0072] SeO 2 (s)+H 2 O(l)=H 2 SeO 3 (l)

[0073] TeO 2 (s)+H 2 O(l)=H 2 TeO 3 (l)

[0074] The copper separation solution is slowly added to the hydrochloric acid solution according to the silver concentration to precipitate silver ions. Sampling is carried out until no white silver chloride precipitates when adding the hydrochloric acid solution as the end point. Silver chloride is added with sodium hydroxide according to the liquid-solid ratio of 2 - 5:1 to adjust the pH value ≥ 11. The reaction temperature is at room temperature. Formaldehyde is slowly added until no solid silver is produced as the end point. The reduction time is 2 - 4 h to generate solid silver and obtain the silver-reduced solution, which is recycled after treatment in the system.

[0075] Specifically, it can be represented by the following chemical equations:

[0076] Ag 2 SO 4 (l)+2HCl(l)=2AgCl(s)+H 2SO 4 (l)

[0077] 2AgCl(s) + 2NaOH(l) = Ag 2 O(s) + 2NaCl(l) + H 2 O(l)

[0078] Ag 2 O(s) + HCHO(l) = 2Ag(s) + HCOOH(l)

[0079] Sulfur dioxide or sodium sulfite is added to the post - silver - precipitation solution for reduction for 2 - 5 h, the reaction temperature is 80 - 90 °C, and the sulfuric acid concentration is 80 - 120 g / l to obtain a mixed selenium - tellurium residue from the post - silver - precipitation solution and a post - selenium - tellurium - precipitation solution.

[0080] Specifically, it can be represented by the following chemical equations:

[0081] H 2 TeO 3 (l) + 2SO 2 (g) + H 2 O(l) = Te(s) + 2H 2 SO 4 (l)

[0082] H 2 SeO 3 (l) + 2SO 2 (g) + H 2 O(l) = Se(s) + 2H 2 SO 4 (l)

[0083] H 2 TeO 3 (l) + 2Na 2 SO 3 (l) = Te(s) + 2Na 2 SO 4 (l) + H 2 O(l)

[0084] H 2 SeO 3 (l) + 2Na 2 SO 3 (l) = Se(s) + 2Na 2 SO 4 (l) + H 2 O(l)

[0085] Sodium sulfite is added to the filtered mixed selenium-tellurium residue to leach selenium. The liquid-solid ratio is 4:1, and the reaction is carried out at room temperature. The molar excess coefficient of sodium sulfite and selenium is 2 - 5 times, and the reaction time is 3 - 5 h to obtain a selenium leaching solution (sodium selenosulfate) and tellurium residue. Liquid sulfuric acid is added to the selenium leaching solution for reduction to obtain crude selenium.

[0086] Specifically, it can be represented by the following chemical equations:

[0087] Se(s) + Na 2 SO 3 (l) = Na 2 SeSO 3 (l)

[0088] Na 2 SeSO 3 (l) + H 2 SO 4 (l) = Na 2 SO 4 (l) + Se(s) + SO 2 (g) + H 2 O(l)

[0089] The filtered tellurium residue is subjected to a chlorination reaction. The liquid-solid ratio is 5:1, the reaction temperature is 80 - 90 °C, and the reaction time is 3 - 4 h. Chlorine or sodium chlorate (molar ratio of tellurium: NaClO 3 = 1:2 - 5), and hydrochloric acid are added. Tellurium enters the tellurium leaching solution in the form of tellurous acid, and the remaining heavy metal impurities enter the tellurium leaching solution in the form of chlorides. After the tellurium residue is completely dissolved and cooled to room temperature, sodium sulfide or sodium hydrosulfide is added to remove heavy metal impurities in the tellurium leaching solution to obtain a post-sulfidation solution and a sulfide residue. The tellurium residue and the sulfide residue contain impurities such as copper, lead, arsenic, antimony, and bismuth, and the tellurium residue and the sulfide residue are returned to the copper smelting system.

[0090] Specifically, it can be represented by the following chemical equations:

[0091] Te(s) + 3H 2 O(l) + 2Cl 2 (g) = H 2 TeO 3 (l) + 4HCl(l)

[0092] NaClO 3 (l) + 6HCl(l) = NaCl(l) + 3Cl 2 (g) + 3H 2 O(l)

[0093] Me(s) + 2HCl(l) = MeCl 2 (l) + H 2 (g)

[0094] MeCl 2 (l) + Na 2 S(l) = MeS(s) + 2NaCl(l)

[0095] Gaseous sulfur dioxide is added to the filtered post - sulfidation solution to reductively obtain tellurium powder and post - tellurium - precipitation solution from the post - sulfidation solution. The reaction temperature is 85 - 95 °C, the reaction time is 2 - 4 h, and the wastewater from the solution after tellurium powder reduction is reused after treatment.

[0096] Specifically, it can be represented by the following chemical equation:

[0097] H 2 TeO 3 (l) + 2SO 2 (g) + H 2 O(l) = Te(s) + 2H 2 SO 4 (l)

[0098] The contents of selenium, tellurium, chloride ions, and particulate matter in the post - tellurium - precipitation solution are detected. The post - tellurium - precipitation solution with selenium and tellurium < 0.05 g / L and chloride ions < 0.1 g / L is precisely filtered to remove fine particulate matter larger than 1 μm in the post - tellurium - precipitation solution. The post - tellurium - precipitation solution meeting the preset standard is subjected to electrowinning for copper removal through a purification system. The copper - separating solution and the electrolyte are mixed in a certain proportion, the copper ion concentration is controlled below 25 g / L, and the current density is controlled at 250 - 300 A / m 3 , and it flows into the electrowinning cell for copper electrowinning at a flow rate of 40 - 60 l / min. Electrowon copper is obtained at the cathode, and the acid in the copper electrolysis system is incremented and returned to the acid leaching and copper - separating process as supplementary acid.

[0099] Specifically, it can be represented by the following chemical equation:

[0100] CuSO 4 (l) + H 2 O(l) = Cu(s) + H 2 SO 4 (l) + 1 / 2O 2 (g)

[0101] In summary, the method for recovering silver, selenium, tellurium, and copper from copper separating solution according to the embodiments of the present invention includes: subjecting roasted slag to acid leaching reaction to obtain copper separating solution; wherein, the copper separating solution contains liquid copper sulfate, liquid nickel sulfate, liquid silver sulfate, liquid selenous acid, and liquid tellurous acid; reducing to obtain solid silver from the copper separating solution by using hydrochloric acid, basic medium, and formaldehyde, and obtaining silver-reduced solution; reducing to obtain mixed selenium-tellurium slag from the silver-precipitated solution by using sulfur dioxide and / or sodium sulfite, and obtaining selenium- and tellurium-precipitated solution; wherein, the silver-precipitated solution contains liquid selenous acid and liquid tellurous acid; adding sodium sulfite to the mixed selenium-tellurium slag to leach selenium to obtain selenium-leaching solution and tellurium slag, adding sulfuric acid to the selenium-leaching solution to obtain crude selenium; subjecting the tellurium slag to chlorination reaction to obtain tellurium-leaching solution and tellurium slag, adding sodium sulfide or / and sodium hydrosulfide to the tellurium-leaching solution for sulfurization impurity removal to remove heavy metal impurities in the tellurium-leaching solution, and obtaining sulfurized solution and sulfurized slag; wherein, the sulfurized solution contains liquid tellurous acid; reducing to obtain tellurium powder and tellurium-precipitated solution from the sulfurized solution by using sulfur dioxide; subjecting the tellurium-precipitated solution meeting the preset standard to electrowinning copper removal through a purification system to produce electrowon copper and secondary copper-removed final solution; wherein, the secondary copper-removed final solution contains sulfuric acid. Thus, this method can effectively recover valuable metals such as silver, selenium, and tellurium, improve the direct recovery rate and recovery rate of silver and tellurium, control the contents of selenium, tellurium, chlorine, and particulate matter entering the electrolytic purification system, improve the product quality and production efficiency of electrolytic cathode copper, reduce the external discharge amount of wastewater, and enhance the environmental protection governance ability.

[0102] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should have the ordinary meanings understood by those of ordinary skill in the art to which the present invention belongs. The "first", "second", and similar terms used in the embodiments of the present invention do not denote any order, quantity, or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative position relationships, and when the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0103] Although the spirit and principles of the present invention have been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the specific embodiments disclosed, and the division of each aspect does not mean that the features in these aspects cannot be combined for benefit. Such a division is only for convenience of expression. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the appended claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A method for recovering silver, selenium, tellurium and copper from a copper separation solution, characterized in that: include: The roasted slag is subjected to an acid leaching reaction to obtain a copper separation liquid; wherein the copper separation liquid contains liquid copper sulfate, liquid nickel sulfate, liquid silver sulfate, liquid selenious acid and liquid tellurous acid; Using hydrochloric acid, alkaline medium and formaldehyde to reduce the copper separation liquid to obtain solid silver and obtain a silver reduction liquid; Using sulfur dioxide and / or sodium sulfite to reduce the silver precipitation liquid to obtain a mixed selenium-tellurium slag, and obtain a selenium-tellurium precipitation liquid; wherein the silver precipitation liquid contains liquid selenious acid and liquid tellurous acid; Sodium sulfite is added to the mixed selenium-tellurium slag to leach selenium, thereby obtaining a selenium leaching solution and tellurium slag, and sulfuric acid is added to the selenium leaching solution to obtain crude selenium; Carrying out a chlorination reaction on the tellurium slag to obtain a tellurium leaching solution and a tellurium slag, adding sodium sulfide and / or sodium hydrosulfide to the tellurium leaching solution for sulfidation and impurity removal to remove heavy metal impurities in the tellurium leaching solution, and obtaining a sulfided solution and sulfided slag; wherein the sulfided solution contains liquid tellurous acid; Using sulfur dioxide to reduce the sulfidized liquid to obtain tellurium powder and tellurium precipitation liquid; The tellurium-deposited liquid that meets the preset standards is subjected to electrolytic copper removal through a liquid purification system to produce electrolytic copper and secondary copper removal final liquid; wherein the secondary copper removal final liquid contains sulfuric acid.

2. The method for recovering silver, selenium, tellurium and copper from copper separation solution according to claim 1, characterized in that: The method also includes acid leaching the roasted slag using the secondary decopperization final solution.

3. The method for recovering silver, selenium, tellurium and copper from copper separation solution according to claim 2, characterized in that: The roasted slag mainly includes solid copper sulfate, solid nickel sulfate, solid silver sulfate, solid selenium dioxide, solid tellurium dioxide, lead sulfate, etc.; The calcined slag is subjected to an acid leaching reaction to obtain a copper separation liquid; wherein the copper separation liquid mainly contains liquid copper sulfate, liquid nickel sulfate, liquid silver sulfate, liquid selenious acid and liquid tellurous acid, including: The selenium content of the roasted slag is controlled to be less than 0.1%, the sulfuric acid concentration used in the acid leaching reaction is 80-120 g / L, the liquid-solid ratio of the sulfuric acid to the roasted slag is 4:1, the reaction temperature is 70-90° C., and the reaction time is 4-5 hours.

4. The method for recovering silver, selenium, tellurium and copper from copper separation solution according to claim 3, characterized in that: The method of reducing the copper separation liquid with hydrochloric acid, alkaline medium and formaldehyde to obtain solid silver and silver reduction liquid comprises: According to the silver concentration of the copper separation solution, slowly add hydrochloric acid solution to precipitate silver ions, and take a sample and dropwise add hydrochloric acid until no white silver chloride is precipitated, which is the reaction end point; Silver chloride continues to add sodium hydroxide at a liquid-to-solid ratio of 2-5:1, adjust the pH value ≥ 11, the reaction temperature is room temperature, and formaldehyde is slowly added dropwise until no silver powder is produced, which is the reaction end point. The reduction time is 2-4h.

5. The method for recovering silver, selenium, tellurium and copper from copper separation solution according to claim 4, characterized in that: The method of reducing the silver precipitation liquid with sulfur dioxide and / or sodium sulfite to obtain a mixed selenium-tellurium slag and a selenium-tellurium precipitation liquid comprises: Sulfur dioxide or sodium sulfite is added to the silver precipitation liquid, the reduction reaction time is 2-5 hours, and the reaction temperature is 80-95°C.

6. The method for recovering silver, selenium, tellurium and copper from copper separation liquid according to claim 5, characterized in that: The method comprises: adding sodium sulfite to the mixed selenium-tellurium slag to leach selenium to obtain a selenium leaching solution and tellurium slag, and adding sulfuric acid to the selenium leaching solution to obtain crude selenium, comprising: Sodium sulfite is added to the filtered mixed selenium-tellurium slag to leach selenium, with a liquid-to-solid ratio of 4:1, and the reaction is carried out at room temperature. The molar excess coefficient of sodium sulfite and selenium is 2-5 times, and the reaction time is 3-5 hours.

7. The method for recovering silver, selenium, tellurium and copper from copper separation solution according to claim 6, characterized in that: The process of subjecting the tellurium slag to a chlorination reaction to obtain a tellurium leaching solution and a tellurium slag, and adding sodium sulfide or / and sodium hydrosulfide to the tellurium leaching solution for sulfidation and impurity removal to remove heavy metal impurities in the tellurium leaching solution to obtain a sulfided solution and sulfided slag comprises: The tellurium slag is subjected to chlorination reaction, with a liquid-solid ratio of 5:1, a reaction temperature of 80-95°C, and a reaction time of 3-4h, and chlorine gas or sodium chlorate and hydrochloric acid are added, and tellurium enters the solution in the form of tellurous acid and the remaining impurity heavy metals enter the solution in the form of chlorides; wherein the molar ratio of tellurium to sodium chlorate is 1:2-5; After the tellurium slag is completely dissolved and cooled to room temperature, sodium sulfide or sodium hydrosulfide is added to remove heavy metal impurities in the solution.

8. The method for recovering silver, selenium, tellurium and copper from copper separation solution according to claim 7, characterized in that: The method of reducing the sulfidized liquid with sulfur dioxide to obtain tellurium powder and the tellurium precipitation liquid comprises: The filtered sulfidized liquid is reduced with sulfur dioxide to obtain tellurium powder. The reaction temperature is 85-95°C and the reaction time is 2-4h.

9. The method for recovering silver, selenium, tellurium and copper from copper separation solution according to claim 8, characterized in that: The process of subjecting the tellurium-deposited liquid that meets the preset standards to electrolytic copper removal through a liquid purification system to produce electrolytic copper and secondary copper removal final liquid includes: The tellurium precipitation solution with selenium and tellurium <0.05g / L and chloride ion <0.1g / L is finely filtered to remove fine particles larger than 1μm in the solution, and then enters the liquid purification system for electrolytic copper removal. The copper solution and the first electrolytic solution are mixed according to the preset ratio to control the copper ion concentration below 25g / L and the current density at 250-300A / m 3 , flows into the electrowinning cell at a flow rate of 40-60L / min for copper electrowinning, and electrowinning copper is obtained at the cathode.

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