A fully wet, multi-stage, high-efficiency method for the separation and recovery of copper, selenium, and tellurium from copper anode slime.

Abstract

This invention discloses a fully wet, stepwise, and efficient method for the recovery of copper, selenium, and tellurium from copper anode mud, comprising the following steps: (1) leaching the copper anode mud with sodium sulfide solution, separating the solid and liquid to obtain tellurium-removed slag and tellurium-containing leachate, and reducing and recovering tellurium from the tellurium-containing leachate to obtain crude tellurium powder; (2) treating the tellurium-removed slag with oxygen-pressure alkaline leaching, separating the solid and liquid to obtain selenium-removed slag and selenium-containing leachate; reducing and recovering selenium from the selenium-containing leachate after acidification to obtain crude selenium powder; (3) leaching the selenium-removed slag with sulfuric acid solution, separating the solid and liquid to obtain acid leaching slag and copper-containing leachate; extracting and back-extracting the copper-containing leachate to obtain copper sulfate. The present invention proposes an innovative "sulfidation for tellurium separation, oxygen pressure alkaline leaching for selenium separation, and acid leaching for copper separation" process for the efficient separation and recovery of copper, selenium, and tellurium from copper anode mud. This process can achieve selective separation and recovery of copper, selenium, and tellurium from anode mud, with a short process flow, high metal separation degree, and high recovery rate.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgy, and particularly relates to a method for recovering copper anode mud. Background Technology

[0002] During the electrolytic refining of crude copper, negatively charged metals such as As and Cu (relative to Cu) on the anode dissolve into the electrolyte under the action of direct current, while positively charged metals such as Au, Ag, Pt, and Pd do not chemically dissolve and fall off with the residual electrode to the bottom of the electrolytic cell, forming copper anode sludge. The yield of copper anode sludge is typically 0.2-0.8% of the crude copper mass, containing 10-30% Cu, 1-15% Se, 0.2-6% Te, 0.01-3% Au, 5-20% Ag, and a small amount of platinum group metals. To efficiently recover precious metals and platinum group metals from the anode sludge, it needs to be pretreated to remove some base metals. Selenium and tellurium are typical rare and dispersed metals, widely used in metallurgy, petrochemicals, electronics, electrical engineering, and defense industries. Tellurium, in particular, is hailed as the "vitamin of modern industry, defense, and cutting-edge technology." Copper in copper anode mud mainly exists as amorphous compounds composed of Cu, CuSO4, CuO, or Cu-Se-Te, while selenium and tellurium mainly exist as selenides or tellurides of copper or silver. These compounds are very stable, making the extraction process of rare and dispersed metals very difficult.

[0003] The main processes for treating copper anode slime include traditional pyrometallurgical processes, semi-wet processes, combined beneficiation and smelting processes, fully wet processes, and Kaldor furnace processes. The extraction methods for copper, selenium, and tellurium differ among these processes.

[0004] Traditional pyrometallurgical processes first employ sulfation roasting to separate selenium. During roasting, the temperature is controlled at 500-600℃, at which point Se oxidizes to SeO2, which volatilizes into the flue gas. SO2 in the flue gas can reduce it back to crude selenium. The acid leaching process uses dilute sulfuric acid as the leaching agent and air as the oxidant to efficiently separate copper from the roasted sand. After sulfation roasting, the copper in the anode mud is converted to water-soluble CuSO4. The copper-removed slag undergoes a "lead reduction smelting - silver separation oxidation refining" process to produce soda slag, which is then leached using alkaline methods to recover tellurium. This lengthy process results in excessive dispersion of Se and Te, with recovery rates of only 90% and 70%, respectively.

[0005] The semi-wet process uses "low-temperature oxidative roasting-acidic leaching with sulfuric acid and sodium chloride" to recover Cu, Se and Te. Se volatilizes into the flue gas, while Cu and Te dissolve into the acidic leachate. This process has advantages such as short production cycle and low environmental pollution, but problems such as poor metal separation effect and severe equipment corrosion have not been solved.

[0006] In the pretreatment stage of the combined beneficiation and smelting process, sodium chlorate is used to oxidize and leach Cu, Se and Te from the anode mud. This process eliminates the rotary kiln roasting and precious lead furnace smelting processes, greatly reducing production energy consumption. However, a small amount of precious metals such as Au and Pd enter the solution, which is not conducive to recovery.

[0007] The all-wet process involves pre-removing copper using a dilute sulfuric acid-air system. The copper-removed slag is then treated with oxidants such as chlorine in a sulfuric acid or sulfuric acid-hydrochloric acid mixture to convert selenium into selenite and tellurium into telluric acid or tellurite. After filtration, a reducing agent is used to reduce selenium and tellurium from the solution. This process offers high selenium recovery, but it is not conducive to the separation of selenium and tellurium, and it consumes a large amount of oxidant.

[0008] The Kaldo furnace process separates copper and tellurium from anode mud through a two-stage pretreatment process of "atmospheric leaching - pressurized acid leaching". The atmospheric leaching process recovers CuO, Cu2O, and CuSO4 from the copper anode mud. Typical process conditions are controlled as follows: sulfuric acid concentration 100-180 g / L, leaching temperature 65-85℃, and blasting time 5 h. After the reaction, the filter residue is pumped into an autoclave for further removal of Cu and Te. At this stage, Cu2S, Cu2Se, and Cu2Te phases are oxidized and enter the pressurized leaching solution, achieving good separation of copper, tellurium, and other metals. Selenium is oxidized to SeO2 during smelting in the Kaldo furnace and volatilizes into the flue gas. After reduction with SO2, crude selenium is obtained. However, this process suffers from problems such as large flue gas volume and low recovery rate, and also generates a large amount of metallurgical slag during the smelting process.

[0009] As can be seen from the above, existing technologies for treating copper anode sludge suffer from difficulties in achieving short processing steps, high recovery rates, and efficient separation of Cu, Se, and Te. Therefore, it is of great significance to provide a method that improves the recovery rate of rare and dispersed metals in copper anode sludge while shortening the processing flow and achieving better metal separation. Summary of the Invention

[0010] The technical problem to be solved by this invention is to overcome the shortcomings and defects mentioned in the background art above, and to provide a fully wet, multi-stage, high-efficiency method for the separation and recovery of copper, selenium, and tellurium from copper anode mud, which features high metal recovery rate, short process flow, and good metal separation effect. To solve the above technical problem, the technical solution proposed by this invention is as follows:

[0011] A fully wet, multi-stage, high-efficiency method for the separation and recovery of copper, selenium, and tellurium from copper anode mud includes the following steps:

[0012] (1) The copper anode mud is leached with sodium sulfide solution, and the solid and liquid are separated to obtain tellurium-free residue and tellurium-containing leachate. Tellurium is reduced and recovered from the tellurium-containing leachate to obtain crude tellurium powder.

[0013] (2) The tellurium-depleted residue is treated by oxygen pressure alkaline leaching, and solid-liquid separation is performed to obtain selenium-depleted residue and selenium-containing leachate; the selenium-containing leachate is acidified and then reduced to recover selenium to obtain crude selenium powder.

[0014] (3) The deselenized residue is leached with sulfuric acid solution, and then the solid and liquid are separated to obtain acid leaching residue and copper-containing leachate; the copper-containing leachate is extracted and back-extracted to obtain copper sulfate.

[0015] In the above-mentioned recycling method, preferably, when leaching copper anode mud with sodium sulfide solution, the copper anode mud is mixed with 60-150 g / L sodium sulfide solution to obtain slurry, the solid-liquid ratio is controlled at 0.1-0.25 g / mL, the reaction temperature is 70-100℃, the stirring rate is 300-500 rpm, and the reaction time is 1-3 h.

[0016] In the above recovery method, preferably, the tellurium-containing leachate is reduced and precipitated by Na2SO3 or SO2, the excess coefficient of Na2SO3 or SO2 is controlled to be 1.5-3 times, the reaction temperature is 20-40℃, and the reaction time is 15-30 min.

[0017] In the above-mentioned recovery method, preferably, when treating the tellurium-depleted residue using oxygen-pressure alkaline leaching, the tellurium-depleted residue is mixed with a 3.0-4.0 mol / L NaOH solution to obtain a slurry. The temperature of the slurry is controlled at 200-250℃, and the solid-liquid ratio is controlled at 0.125-0.25 g / mL during mixing. After the temperature is raised to the preset temperature, oxygen is introduced, and the oxygen partial pressure of the system is controlled at 1.8-2.3 MPa. The reaction is carried out for 2-4 hours. The above process conditions can improve the leaching rate of selenium and simultaneously oxidize Cu2S to Cu2O as completely as possible, facilitating the separation and recovery of copper. In particular, the concentration of NaOH solution and the control of oxygen partial pressure have a significant impact on the subsequent copper leaching.

[0018] In the above recovery method, preferably, the selenium-containing leachate is acidified using the waste acid generated after extraction in step (3), and the amount of waste acid added is controlled to be 10-20% of the total volume of the selenium-containing leachate. Hexavalent Se is difficult to be reduced kinetically. The present invention first acidifies and then reduces, which is beneficial to the recovery of selenium.

[0019] In the above-mentioned recovery method, preferably, after acidification, the selenium-containing leachate is reduced and precipitated by Na2SO3 or SO2, with the excess coefficient of Na2SO3 or SO2 controlled at 1.5-2 times, the reaction temperature at 30-70℃, and the reaction time at 0.5-1h.

[0020] In the above-mentioned recovery method, preferably, when the selenium-depleted residue is leached with sulfuric acid solution, the selenium-depleted residue is mixed with 1-3 mol of H2SO4 solution to obtain a slurry. The temperature of the slurry is controlled at 50-70℃, the solid-liquid ratio is controlled at 0.125-0.25 g / mL during mixing, air is introduced during the reaction, and the air flow rate is controlled at 0.1-0.5 L / min. The reaction is carried out for 1-3 hours.

[0021] In the above recovery method, preferably, AD-100 is used as the extractant and sulfonated kerosene is used as the diluent during the extraction of copper-containing leachate. The O:A ratio is controlled at (2-3):1, the volume concentration of the extractant is 15-20%, the initial pH value is 2.0-2.5, and after extraction for 10-20 min, the mixture is allowed to stand and clarify before separation to obtain a copper-rich organic phase. The copper-rich organic phase is then washed with 1-2 mol / L dilute sulfuric acid for 15-20 min before separation to obtain a copper sulfate solution, which is then evaporated and crystallized to obtain copper sulfate.

[0022] The technical principle of this invention is as follows: First, copper anode mud is subjected to a sulfidation leaching process to selectively leach tellurium. During this process, selenium and copper are enriched in the leaching residue (de-tellurium residue), while tellurium is enriched in the leachate (tellurium-containing leachate). The tellurium-containing solution is then reduced and recovered using Na2SO3 or SO2. Crude tellurium powder is obtained by filtration and further refined to obtain metallic tellurium. The de-tellurium residue is then subjected to an oxygen-pressure alkaline leaching process to selectively separate selenium. During this process, selenium and copper are enriched in the leachate (selenium-containing leachate) and the leaching residue (de-selenium residue), respectively. In the process of deselenization, the selenium-containing solution is acidified and then reduced with Na2SO3 or SO2 to recover the selenium. The crude selenium powder is obtained by filtration and further refined to obtain metallic selenium. Copper in the deselenized residue mainly exists in oxide form. A normal-pressure acid leaching process is used to recover the copper, at which point all the copper is concentrated in the leaching solution (copper-containing leaching solution). The copper-containing leaching solution is selectively separated from the copper using AD-100 extractant. The copper-rich organic phase is back-extracted with dilute sulfuric acid to obtain a copper sulfate solution, which is then evaporated and crystallized to obtain the copper sulfate product. Specifically:

[0023] In step (1), the ionic composition of the alkaline sulfidation system (sodium sulfide solution) is complex. When copper anode mud is added to the alkaline sulfidation system, tellurium-containing phases such as Ag2Te and Cu2Te will react with sodium sulfide to generate S. 2- HS - S2O3 2- The plasma reacts to transform it into TeS3. 2- Or TeS4 2- During leaching, heavy metal ions such as Cu precipitate as Me₂S, which, along with unreacted selenides, remain in the leaching residue, achieving selective extraction of tellurium. The chemical equations potentially involved in this process are as follows:

[0024] Me2Te+Na2S+3S=Na2TeS3+Me2S;

[0025] MeTe + Na2S + 3S = Na2TeS3 + MeS;

[0026] Me2Te3+3Na2S+6S=3Na2TeS3+Me2S3;

[0027] Me2Te3+3Na2S+6S=3Na2TeS3+Me2S3.

[0028] In step (2), Se dissolves in large quantities in the alkaline sodium hydroxide system as Na2SeO3 or Na2SeO4. Then, through process control, copper, existing as Cu2S, is converted into readily reactant Cu2O and CuO in this step, precipitating in the selenium-removing slag, thus achieving selective separation and recovery of selenium. The chemical equations that may be involved in this process are as follows:

[0029] 2Se+4NaOH+3O2=2Na2SeO4+2H2O;

[0030] Ag2Se+2NaOH+2O2=Na2SeO4+Ag2O+H2O;

[0031] 2Cu2Se+4NaOH+5O2=2Na2SeO4+4CuO+2H2O;

[0032] 2CuAgSe+2NaOH+5O2=2Na2SeO4+2CuO+Ag2O+H2O;

[0033] 2Cu2S+4NaOH+5O2=2Na2SO4+4CuO+2H2O.

[0034] In step (3), after the selenium-removed slag is alkaline leached with sodium hydroxide, Cu mainly exists in the form of CuO and Cu2O, with a small amount of Cu2S and CuS. At this time, the material readily reacts with sulfuric acid to generate CuSO4, which dissolves into the leachate. Au, Ag, and other precious metals do not react and precipitate in the copper-removed slag, thus achieving selective separation and recovery of copper. The chemical equations that may be involved in this process are as follows:

[0035] 2Cu+2H2SO4+O2=2CuSO4+2H2O;

[0036] Cu₂O + H₂SO₄ = Cu + CuSO₄ + H₂O;

[0037] 2CuS+2H2SO4+O2=2CuSO4+2H2O+2S;

[0038] CuO + H₂SO₄ = CuSO₄ + H₂O;

[0039] 2Cu2O+4H2SO4+O2=4CuSO4+4H2O.

[0040] The present invention discloses a fully wet, stepwise, and highly efficient method for the separation and recovery of copper, selenium, and tellurium from copper anode mud. This method uses sodium sulfite as a reducing agent for selenium-containing tellurium leachate, and can prepare crude selenium and crude tellurium products in one step. It avoids the sulfation roasting process in traditional selenium production and the "alkali leaching-neutralization precipitation-alkali dissolution electrolysis" process in traditional tellurium production. This process can significantly shorten the process flow and achieve efficient and clean extraction of selenium and tellurium through a short process.

[0041] In the fully wet, stepwise, and highly efficient method for the separation and recovery of copper, selenium, and tellurium from copper anode mud of the present invention, the selective separation and recovery effect of copper, selenium, and tellurium is optimal and the metal recovery rate is highest through the synergistic effect of each process step and process parameter.

[0042] Compared with other technologies, the advantages of this invention are:

[0043] 1. The invention proposes an innovative wet-step-by-step high-efficiency separation and recovery method for copper, selenium and tellurium from copper anode mud. This method involves a new process of "sulfidation for tellurium separation - oxygen pressure alkaline leaching for selenium separation - acid leaching for copper separation". This process can achieve selective separation and recovery of copper, selenium and tellurium from anode mud. The process is short, with high metal separation and high recovery rate.

[0044] 2. The fully wet, stepwise, and efficient method for the separation and recovery of copper, selenium, and tellurium from copper anode mud of the present invention uses a sodium sulfide alkaline system in the tellurium separation process, which can achieve efficient separation and extraction of tellurium. This system has strong adaptability to raw materials, can process different types of copper anode mud, and is easy to implement on a large scale.

[0045] 3. The fully wet, stepped, high-efficiency separation and recovery method for copper, selenium, and tellurium from copper anode mud of the present invention has low energy consumption, simple operation, low production and investment costs, and the copper-removed slag produced can be directly used for precious metal recovery. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a process flow diagram of the fully wet, stepped, and efficient method for the recovery of copper, selenium, and tellurium from copper anode mud according to the present invention.

[0048] Figure 2 The process flow diagram shows the fully wet cascade separation and recovery method for copper, selenium, and tellurium from copper anode mud, which is Comparative Example 1. Detailed Implementation

[0049] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0050] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0051] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0052] The elemental contents of the copper anode slime treated in the following examples and comparative examples are shown in Table 1 below.

[0053] Table 1: Chemical composition (%) of copper anode mud

[0054] element Cu Se Te Au Ag As content 21.86 10.56 4.32 0.18 13.14 2.44

[0055] Example 1:

[0056] like Figure 1 As shown, a method for recovering Cu, Se, and Te using a fully wet process from copper anode mud includes the following steps:

[0057] (1) Take 10g of copper anode mud, add 60g / L Na2S solution to slurry it, and then place it in a constant temperature water bath. During the leaching process, control the water bath temperature at 80℃, the stirring speed at 300rpm, and the liquid-solid ratio at 8:1mL / g. After reacting for 2h, filter to obtain tellurium-free slag and tellurium-containing leachate. At this time, the leaching rates of Cu, Se and Te are 0.04%, 1.80% and 89.15%, respectively, and the tellurium content in the tellurium-free slag is 0.58wt%, achieving efficient separation of Te from Cu and Se.

[0058] (2) Add Na2SO3 with an excess coefficient of 2.0 to the tellurium-containing leachate obtained in step (1), control the reaction temperature at 25℃ and the reaction time at 15min, at which point the precipitation rate of Te reaches 96.84%, and the crude tellurium is vacuum distilled to obtain metallic tellurium with a purity of 99.99%; thus achieving selective precipitation separation of Te.

[0059] (3) The tellurium-depleted residue obtained in step (1) was added to a high-pressure reactor, and 3.0 mol / L NaOH solution was added to slurry it. The leaching process was controlled at a temperature of 230℃, a stirring speed of 300 rpm, a liquid-to-solid ratio of 5:1 mL / g, and an oxygen partial pressure of 2.0 MPa. After reacting for 2 hours, the selenium-depleted residue and selenium-containing leachate were obtained by filtration. At this time, the leaching rates of Cu, Se and Te were 0.1%, 97.69% and 0.5%, respectively, and the selenium content in the selenium-depleted residue was 0.84 wt%. The selenium-containing leachate was alkaline, and hexavalent selenium was difficult to reduce. The leachate was acidified by using the waste acid generated after extraction in step (3). 15% waste acid and 1.5 times excess Na2SO3 were added. The reaction temperature was controlled at 50℃ and the reaction time was 60 min. At this time, the precipitation rate of Se reached 96.56%. The crude selenium was vacuum distilled to obtain metallic selenium with a purity of 99.99%, thus achieving efficient separation and extraction of Se.

[0060] (4) The selenium-removed slag obtained in step (3) was added to a 1.5 mol / L H2SO4 solution for slurrying. The leaching process was controlled with a water bath temperature of 50℃, a stirring speed of 300 rpm, a liquid-to-solid ratio of 5:1 mL / g, and an aeration rate of 0.1 L / min. After 2 h of reaction, the copper-removed slag and copper-containing leachate were obtained by filtration, at which point the Cu leaching rate was 96.56%. The copper-containing leachate was extracted using AD-100 as the extractant and sulfonated kerosene as the diluent. Under the optimal process conditions of an extractant concentration of 15%, a reaction time of 10 min, a phase ratio (O / A) of 2.5:1, a reaction temperature of 25℃, and an initial pH of 2.5, the Cu extraction rate was 96.65%. The copper-rich organic phase was washed in 1 mol / L H2SO4 to obtain a copper sulfate solution with high purity. After evaporation and crystallization, 5H2O·CuSO4 was prepared, achieving selective and efficient extraction of Cu.

[0061] Example 2:

[0062] like Figure 1 As shown, a method for recovering Cu, Se, and Te using a fully wet process from copper anode mud includes the following steps:

[0063] (1) Take 100g of copper anode mud and add 100g / L Na2S solution to slurry it. During the leaching process, control the temperature of the water bath at 90℃, the stirring speed at 300rpm, and the liquid-to-solid ratio at 10:1mL / g. After reacting for 2h, filter to obtain tellurium-depleted residue and tellurium-containing leachate. At this time, the leaching rates of Cu, Se, and Te are 0.02%, 3.2%, and 90.23%, respectively, and the tellurium content in the tellurium-depleted residue is 0.43wt%.

[0064] (2) Add excess Na2SO3 with a coefficient of 2.0 to the tellurium-containing leachate obtained in step (1), control the reaction temperature at 30℃ and the reaction time at 20min. At this time, the precipitation rate of Te reaches 97.54%, and the crude tellurium is vacuum distilled to obtain metallic tellurium with a purity of 99.99%; the selective precipitation separation of Te is achieved.

[0065] (3) The tellurium-depleted residue obtained in step (1) was added to a high-pressure reactor and slurried with 4.0 mol / L NaOH solution. The leaching process was controlled at a temperature of 230℃, a stirring speed of 300 rpm, a liquid-to-solid ratio of 8:1 mL / g, and an oxygen partial pressure of 2.3 MPa. After 3 h of reaction, the selenium-depleted residue and selenium-containing leachate were obtained by filtration. At this time, the leaching rates of Cu, Se and Te were 0.01%, 98.52% and 0.94%, respectively, and the selenium content in the selenium-depleted residue was 0.76 wt%. The selenium-containing leachate was alkaline, and hexavalent selenium was difficult to reduce. The leachate was acidified by using the waste acid generated after extraction in step (3). 15% waste acid and 2.0 times excess Na2SO3 were added. The reaction temperature was controlled at 70℃ and the reaction time was 60 min. At this time, the precipitation rate of Se reached 96.80%. The crude selenium was vacuum distilled to obtain metallic selenium with a purity of 99.99%, thus achieving efficient separation and extraction of Se.

[0066] (4) The selenium-removed slag obtained in step (3) was added to a 3 mol / L H2SO4 solution. During the leaching process, the temperature of the water bath was controlled at 50℃, the stirring speed at 300 rpm, the liquid-to-solid ratio at 8:1 mL / g, and the aeration rate at 0.3 L / min. After reacting for 2 h, the copper-removed slag and copper-containing leachate were obtained by filtration. At this time, the Cu leaching rate was 97.42%. The copper-containing leachate was extracted using AD-100 as the extractant and sulfonated kerosene as the diluent. Under the optimal process conditions of 15% extractant concentration, 10 min reaction time, 3:1 ratio (O / A), 25℃ reaction temperature, and 2.5 initial pH, the Cu extraction rate was 96.32%. The copper-rich organic phase was washed in 1 mol / L H2SO4 to obtain a copper sulfate solution with high purity. After evaporation and crystallization, 5H2O·CuSO4 was prepared, achieving selective and efficient extraction of Cu.

[0067] Comparative Example 1:

[0068] like Figure 2 As shown, the method for recovering Cu, Se, and Te using a fully wet process from copper anode slime in this comparative example includes the following steps:

[0069] (1) Take 100g of copper anode mud, add 3mol / L NaOH solution to slurry it, and then place it in a high-pressure reactor. The leaching process is controlled at a temperature of 200℃, a stirring speed of 300rpm, a liquid-to-solid ratio of 5:1mL / g, and an oxygen partial pressure of 2.0MPa. After reacting for 2 hours, filter to obtain deselenized residue and selenium-containing leachate. At this time, the leaching rates of Cu, Se, and Te are 0.06%, 98.42%, and 1.36%, respectively.

[0070] (2) The selenium-removed residue obtained in step (1) was mixed with 100 g / L Na2S solution and placed in a constant temperature water bath. The reaction temperature was controlled at 85℃, the stirring speed at 300 rpm, and the liquid-solid ratio at 10:1 mL / g. After reacting for 2 h, the tellurium-removed residue and tellurium-containing leachate were obtained by filtration. At this time, the leaching rates of Cu, Se, and Te were 0.1%, 4.62%, and 88.63%, respectively. Excess Na2SO3 with an excess coefficient of 2.0 was added to the tellurium-containing leachate. The reaction temperature was controlled at 25℃ and the reaction time at 15 min. At this time, the precipitation rate of Te reached 96.26%. The crude tellurium was vacuum distilled to obtain metallic tellurium with a purity of 99.99%; the selective precipitation and separation of Te was achieved.

[0071] (3) The selenium-removed slag obtained in step (2) was added to a 2 mol / L H2SO4 solution for slurrying. The leaching process was controlled with the water bath temperature at 50℃, the stirring speed at 300 rpm, and the liquid-to-solid ratio at 10:1 mL / g. After reacting for 2 hours, the copper-removed slag and copper-containing leachate were obtained by filtration. At this time, the Cu leaching rate was only 31.97%, and the copper content in the slag was as high as 21.15%.

[0072] (4) Alternatively, the selenium-removed slag obtained in step (2) is slurried in a 2 mol / L H2SO4 solution. During the leaching process, the water bath temperature is controlled at 50℃, the stirring speed at 300 rpm, the liquid-to-solid ratio at 10:1 mL / g, and the aeration rate at 0.3 L / min. After reacting for 2 hours, the copper-removed slag and copper-containing leachate are obtained by filtration. At this point, the Cu leaching rate is only 37.69%, and the slag contains 19.96% copper.

[0073] Experiments in steps (3) and (4) show that after the "oxygen pressure selenium separation-sulfurization tellurium separation" process, copper in the copper anode mud will be converted into Cu2S precipitate, which is difficult to react and is not conducive to subsequent separation and recovery. However, in steps (1) of Examples 1 and 2, copper in the copper anode mud is converted into Cu2S precipitate in Na2S solution. In step (2), Cu2O and CuO precipitates will be generated in the selenium removal slag. At this time, the copper is easy to react with sulfuric acid and enter the copper-containing solution, thus achieving separation and recovery. At this time, not only the separation and recovery of selenium and tellurium are achieved, but also the efficient separation of copper is achieved, with a copper leaching rate of about 95% and a recovery rate of about 90%.

Claims

1. A fully wet, multi-stage, high-efficiency method for the separation and recovery of copper, selenium, and tellurium from copper anode mud, characterized in that... Includes the following steps: (1) The copper anode mud is leached with sodium sulfide solution, and the solid and liquid are separated to obtain tellurium-free residue and tellurium-containing leachate. Tellurium is reduced and recovered from the tellurium-containing leachate to obtain crude tellurium powder. (2) The tellurium-depleted residue is treated by oxygen pressure alkaline leaching, and solid-liquid separation is performed to obtain deselenized residue and selenium-containing leachate; the selenium-containing leachate is acidified and then reduced to recover selenium to obtain crude selenium powder. (3) The deselenized residue is leached with sulfuric acid solution, and then the solid and liquid are separated to obtain acid leaching residue and copper-containing leachate; the copper-containing leachate is extracted and back-extracted to obtain copper sulfate.

2. The recycling method according to claim 1, characterized in that, When leaching copper anode mud with sodium sulfide solution, the copper anode mud is mixed with 60-150 g / L sodium sulfide solution to obtain a slurry. The solid-liquid ratio is controlled at 0.1-0.25 g / mL, the reaction temperature is 70-100℃, the stirring speed is 300-500 rpm, and the reaction time is 1-3 h.

3. The recycling method according to claim 1, characterized in that, The tellurium-containing leachate is reduced and precipitated by Na2SO3 or SO2. The excess coefficient of Na2SO3 or SO2 is controlled to be 1.5-3 times, the reaction temperature is 20-40℃, and the reaction time is 15-30 min.

4. The recycling method according to claim 1, characterized in that, When treating the tellurium-depleted residue with oxygen-pressure alkaline leaching, the tellurium-depleted residue is mixed with a 3.0-4.0 mol / L NaOH solution to obtain a slurry. The temperature of the slurry is controlled at 200-250℃, and the solid-liquid ratio is controlled at 0.125-0.25 g / mL during mixing. After the temperature is raised to the preset temperature, oxygen is introduced, and the oxygen partial pressure of the system is controlled at 1.8-2.3 MPa. The reaction is carried out for 2-4 hours.

5. The recycling method according to claim 1, characterized in that, The waste acid generated after extraction in step (3) is used to acidify the selenium-containing leachate, and the amount of waste acid added is controlled to be 10-20% of the total volume of the selenium-containing leachate.

6. The recycling method according to claim 1, characterized in that, After acidification, the selenium-containing leachate is reduced and precipitated with Na2SO3 or SO2. The excess coefficient of Na2SO3 or SO2 is controlled to be 1.5-2 times, the reaction temperature is 30-70℃, and the reaction time is 0.5-1h.

7. The recycling method according to any one of claims 1-6, characterized in that, When the deselenate slag is leached with sulfuric acid solution, the deselenate slag is mixed with 1-3 mol of H2SO4 solution to obtain a slurry. The temperature of the slurry is controlled at 50-70℃, and the solid-liquid ratio is controlled at 0.125-0.25 g / mL during mixing. Air is introduced during the reaction, and the air flow rate is controlled at 0.1-0.5 L / min. The reaction is carried out for 1-3 hours.

8. The recycling method according to any one of claims 1-6, characterized in that, When extracting copper-containing leachate, AD-100 was used as the extractant and sulfonated kerosene as the diluent. The O:A ratio was controlled at (2-3):1, the volume concentration of the extractant was 15-20%, the initial pH was 2.0-2.5, and after extraction for 10-20 min, the mixture was allowed to stand and clarify before separation to obtain a copper-rich organic phase. The copper-rich organic phase was washed with 1-2 mol / L dilute sulfuric acid for 15-20 min and then separated to obtain a copper sulfate solution, which was then evaporated and crystallized to obtain copper sulfate.

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