Method for recovering selenium and tellurium from copper anode slime copper separation liquid step by step

Abstract

The invention relates to a method for recycling selenium and tellurium from copper anode slime copper separation liquid step by step, and aims to solve the technical problems that pyrogenic separation is needed after selenium and tellurium are extracted, and the treatment process flow is long. According to the technical scheme, the method comprises the following steps: (1) heating, concentrating, cooling and filtering the copper anode slime copper separation liquid; (2) detecting the content of selenium and tellurium; (3) carrying out sodium hydrogen sulfite reduction on filtrate I to extract selenium; (4) chlorinating filtrate II and then reducing to obtain crude tellurium; after the copper separation liquid is treated step by step, step-by-step recovery of selenium and tellurium in the copper separation liquid is achieved through a one-step method, the recovery process of selenium and tellurium is shortened, the recovery rate of selenium and tellurium in the copper anode slime is increased, and the economic benefits of smelting plants are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of copper anode mud treatment, and in particular relates to a method for recovering selenium and tellurium in steps from copper anode mud copper separation liquid. Background Art

[0002] The precious metal workshop of a copper smelter adopts the process of sulfuric acid roasting + acid leaching for copper separation + chlorination for gold separation + ammonia leaching for silver separation to comprehensively recover precious metals from copper anode mud. In the process of acid leaching for copper separation, selenium and tellurium become corresponding acids and enter the copper separation liquid. Tellurium is a rare metal. Due to its good optical properties, it is widely used in defense, energy, aerospace and other fields, especially its good thermoelectric potential and photoelectric conversion effect. It is the preferred material for refrigeration elements, optical disk targets and gas detectors. Tellurium is a silvery-white semi-metal with stable properties. With the growing demand for refrigeration, the demand for tellurium is in short supply. The price of tellurium has reached almost 700,000 yuan / ton, but because the abundance of tellurium in the earth's crust is only 1×10 -9 The raw materials for tellurium production mainly come from copper anode mud, so it is particularly important to recover tellurium from copper anode mud.

[0003] The tellurium content of copper anode mud reaches 4.3%. During the process of sulfuric acid roasting of copper anode mud, tellurium is oxidized to tellurium dioxide and enters the roasting slag. The roasting slag is leached with sulfuric acid, and tellurium dioxide is converted into telluric acid and enters the acid leaching copper separation liquid. Currently, iron powder is used for replacement to form a selenium-tellurium mixture and sponge copper powder. The selenium-tellurium mixture needs to be re-separated, resulting in a lengthy copper separation liquid treatment process, affecting the recovery rate of selenium and tellurium in the copper separation liquid, and high treatment costs, which in turn affects the economic benefits of the enterprise.

[0004] At present, other copper smelters use iron powder to replace copper liquid, and the generated selenium-tellurium mixture is separated by pyrometallurgy to produce tellurium and selenium. The copper sulfate solution after iron powder replaces selenium and tellurium is returned to the copper electrolytic refining electrolyte purification process, which reduces the amount of iron powder used and the cost of sponge copper smelting and processing, and improves the overall efficiency. However, it is necessary to add a new pyrometallurgical selenium-tellurium separation device, and the processing process is long. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems and provide a method for recovering selenium and tellurium from copper anode mud copper liquid in steps.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for recovering selenium and tellurium from copper anode mud copper separation liquid in steps, comprising the following steps: Step 1) taking copper anode mud and separating the copper liquid, placing it on an electric heating plate or a heating furnace for heating and concentration, first cooling it naturally, then cooling it with water, and filtering it when the temperature drops to room temperature to obtain a filter residue 1, placing the filter residue 1 in a blast drying oven for drying, and then taking it out to form a copper sulfate pentahydrate product, and the filtered filtrate 1 is for standby use; Step 2) respectively detecting the contents of selenium and tellurium in the filtrate 1; Step 3) Dilute the filtrate 1 by half with water, mix well and heat in a constant temperature water bath, add solid sodium bisulfite to the filtrate 1 several times to reduce it to obtain selenium, and then filter to form filtrate 2 and residue 2. The reaction process equation is: H2SeO3+2NaHSO3=Se↓+Na2SO4+H2SO4+H2O; Step 4) Heat the filtrate 2 in a constant temperature water bath, first add sodium chloride or hydrochloric acid to the filtrate 2 several times to chlorinate it, and after the chlorination is completed, add sodium bisulfite to the filtrate 2 for reduction to obtain crude tellurium, filter it to form filtrate 3 and residue 3, and the reaction process equation is: H2TeO3+2NaHSO3=Te↓+Na2SO4+H2SO4+H2O; Step 5) electrolysis is performed using the copper starting plate as the cathode, the insoluble lead plate as the anode, and the filtrate 3 as the electrolyte. The impurity ions in the filtrate 3 enter the copper starting plate to form a black copper plate. After the electrolysis is completed, the electrolyte is converted into sulfuric acid and directly reused in the copper separation process; Furthermore, in the step 1), the copper anode mud is heated and concentrated by 3 to 5 times, the natural cooling time is 30 to 40 minutes, the water cooling time is 5 to 10 minutes, the first component of the filter residue is copper sulfate pentahydrate crystals, and the drying time is ≥ 24 hours.

[0007] Furthermore, in step 3), the constant temperature water bath temperature of the filtrate 1 is 55-80° C., the mass of the sodium bisulfite is 4-6 times the selenium content in the filtrate 1, the reduction time is 0.5-1 h, and the component of the filter residue 2 is red selenium.

[0008] Furthermore, in the step 4), the constant temperature water bath temperature of the filtrate 2 is 85-95° C., the mass of the sodium chloride or hydrochloric acid is 2-5 times the tellurium content in the filtrate 2, the chlorination time is 0.5-1 h, the mass of the sodium bisulfite is 5-8 times the tellurium content in the filtrate 2, the reduction time is 1-1.5 h, and the cost of the filter residue 3 is crude tellurium.

[0009] Furthermore, in step 5), the electrolyte after electrolysis is converted into 25% to 35% sulfuric acid.

[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. After the copper separation liquid of the present invention is processed step by step, the step-by-step recovery of selenium and tellurium in the copper separation liquid is realized by a one-step method, which shortens the recovery process of selenium and tellurium, improves the recovery rate of selenium and tellurium in copper anode mud, and improves the economic benefits of the smelter; 2. The copper liquid separation and step-by-step recovery of selenium and tellurium process of the present invention does not require new equipment and can be carried out using existing equipment, without generating wastewater. The copper liquid separation realizes full process circulation, with “0” wastewater discharge, thus reducing the pressure of rare metal wastewater treatment; 3. The process for recovering selenium and tellurium from copper solution in steps of the present invention is easy to operate, highly automated, safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0013] like Figure 1 As shown, a method for recovering selenium and tellurium from copper anode mud copper liquid in steps comprises the following steps: Step 1) Take 27L of copper anode mud and copper liquid, the chemical composition of which is shown in Table 1, put it on an electric hot plate or a heating furnace to heat and concentrate it to 9L, first cool it naturally for 30 minutes, then water cool it for 10 minutes, and when the temperature drops to room temperature, filter it to obtain a filter residue, put the filter residue into a blast drying oven for drying for 24 hours, take it out to obtain a copper sulfate pentahydrate product, and the filtered filtrate is set aside; Table 1 Chemical composition of copper solution

[0014] Step 2) respectively detecting the contents of selenium and tellurium in the filtrate 1; Step 3) Take 2L of filtrate 1 and dilute it to 4L with water, stir evenly and heat it in a constant temperature water bath at 80°C, add 15g of sodium bisulfite (90g in total) to filtrate 1 every 20 minutes and stir, reduce it for 1 hour, and then filter it while hot to obtain filtrate 2 and residue 2. The composition of residue 2 is single red single selenium, the purity of selenium is ≥99%, the direct recovery rate of selenium reaches 94.93%, and no gray tellurium is generated. The reaction process equation is: H2SeO3+2NaHSO3=Se↓+Na2SO4+H2SO4+H2O; Step 4) Take 3L of filtrate 2, add 120ml of hydrochloric acid to it, stir evenly, and then heat it in a water bath at 80°C to chlorinate it for 1h. After the chlorination is completed, add 10g of sodium sulfite (a total of 120g) to filtrate 2 every 20 minutes and stir, reduce for 1.5 hours, filter while hot to obtain filtrate 3 and filter residue 3. The composition of filter residue 3 is crude tellurium, the purity of crude tellurium is ≥70%, and the direct recovery rate of tellurium reaches more than 70%. The reaction process equation is: H2TeO3+2NaHSO3=Te↓+Na2SO4+H2SO4+H2O; Step 5) With the copper starting plate as cathode and the insoluble lead plate as anode, filtrate three is used as electrolyte for electrolysis. Impurity ions in filtrate three enter the copper starting plate to form a black copper plate. After the electrolysis is completed, the electrolyte is converted into 35% sulfuric acid and directly reused in the copper separation process, achieving "0" wastewater discharge of the copper separation liquid and realizing the recycling of the copper separation liquid.

[0015] In the step 1), the heating and concentration of the copper anode mud and the copper liquid can be any multiple between 3 and 5, the natural cooling time can be any value between 30 and 40 minutes, the water cooling time can be any value between 5 and 10 minutes, and the drying time can be any value ≥ 24 hours; In the step 3), the constant temperature water bath temperature of the filtrate 1 can also be any value between 55 and 80° C., the mass of the sodium bisulfite can also be any value between 4 and 6 times the selenium content in the filtrate 1, and the reduction time can also be any value between 0.5 and 1 h.

[0016] In the step 4), the constant temperature water bath temperature of the filtrate 2 can also be any value between 85 and 95° C., the hydrochloric acid can also be replaced by sodium chloride, the mass of the hydrochloric acid / sodium chloride can also be any value between 2 and 5 times the tellurium content in the filtrate 2, the chlorination time can also be any value between 0.5 and 1 h, the mass of the sodium bisulfite can also be any value between 5 and 8 times the tellurium content in the filtrate 2, and the reduction time can also be any value between 1 and 1.5 h.

[0017] The concentration of sulfuric acid converted from the electrolyte after the electrolysis in step 5) can also be any value between 25% and 35%.

[0018] The copper separation solution, the concentrated copper separation solution, the selenium extraction solution, and the tellurium extraction solution were sampled and analyzed by ICP. The chemical contents in the solutions are shown in Table 2: Table 2 Chemical composition of different solutions (mg / L)

[0019] It can be calculated from Table 3 that the direct recovery rate of copper sulfate is 70.61%, which is relatively low. The higher the concentration multiple, the higher the direct recovery rate, but the higher the content of selenium and tellurium included, the more selenium and tellurium will be lost.

[0020] When the concentrated copper solution was diluted 2 times, 90g of sodium sulfite was added in batches at 80°C. During the reduction process, the volume did not change. A total of 1.583g of selenium was recovered, and the recovery rate of selenium reached 98.76%. At a temperature of 80°C, 120 g of sodium sulfite was added in batches. During the reduction process, a total of 10.3 g of precipitate was produced, 7.4 g of tellurium was recovered, and the direct recovery rate of tellurium was 94.87%. This was mainly because after adding hydrochloric acid / sodium chloride, tellurium was converted into tellurium chloride, thereby improving the reduction effect.

Claims

1. A method for recovering selenium and tellurium from copper anode mud copper liquid in steps, characterized in that: The steps include: Step 1) taking copper anode mud and separating the copper liquid, placing it on an electric heating plate or a heating furnace for heating and concentration, first cooling it naturally, then cooling it with water, and filtering it when the temperature drops to room temperature to obtain a filter residue 1, placing the filter residue 1 in a blast drying oven for drying, and then taking it out to form a copper sulfate pentahydrate product, and the filtered filtrate 1 is for standby use; Step 2) respectively detecting the contents of selenium and tellurium in the filtrate 1; Step 3) Dilute the filtrate 1 by half with water, mix well and heat in a constant temperature water bath, add solid sodium bisulfite to the filtrate 1 several times to reduce it to obtain selenium, and then filter to form filtrate 2 and residue 2. The reaction process equation is: H2SeO3+2NaHSO3=Se↓+Na2SO4+H2SO4+H2O; Step 4) Heat the filtrate 2 in a constant temperature water bath, first add sodium chloride or hydrochloric acid to the filtrate 2 several times to chlorinate it, and after the chlorination is completed, add sodium bisulfite to the filtrate 2 for reduction to obtain crude tellurium, filter it to form filtrate 3 and residue 3, and the reaction process equation is: H2TeO3+2NaHSO3=Te↓+Na2SO4+H2SO4+H2O; Step 5) Use the copper starting plate as the cathode, the insoluble lead plate as the anode, and the filtrate three as the electrolyte for electrolysis. The impurity ions in the filtrate three enter the copper starting plate to form a black copper plate. After the electrolysis is completed, the electrolyte is converted into sulfuric acid and directly reused in the copper separation process.

2. The method for recovering selenium and tellurium from copper anode mud copper separation liquid in steps according to claim 1, characterized in that: In the step 1), the copper anode mud is heated and concentrated by 3 to 5 times, the natural cooling time is 30 to 40 minutes, the water cooling time is 5 to 10 minutes, the first component of the filter residue is copper sulfate pentahydrate crystals, and the drying time is ≥ 24 hours.

3. The method for recovering selenium and tellurium from copper anode mud copper separation liquid in steps according to claim 1, characterized in that: In the step 3), the constant temperature water bath temperature of the filtrate 1 is 55-80° C., the mass of the sodium bisulfite is 4-6 times the selenium content in the filtrate 1, the reduction time is 0.5-1 h, and the component of the filter residue 2 is red selenium.

4. The method for recovering selenium and tellurium from copper anode mud copper separation liquid in steps according to claim 1, characterized in that: In the step 4), the constant temperature water bath temperature of the filtrate 2 is 85-95° C., the mass of the sodium chloride or hydrochloric acid is 2-5 times the tellurium content in the filtrate 2, the chlorination time is 0.5-1 h, the mass of the sodium bisulfite is 5-8 times the tellurium content in the filtrate 2, the reduction time is 1-1.5 h, and the cost of the filter residue 3 is crude tellurium.

5. The method for recovering selenium and tellurium from copper anode mud copper separation liquid in steps according to claim 1, characterized in that: In the step 5), the electrolyte after the electrolysis is converted into 25% to 35% sulfuric acid.

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