A method for quickly separating and recovering tellurium from copper anode slime

Abstract

The application discloses a method for rapidly separating and recovering tellurium from copper anode slime, which comprises the following steps: mixing coal powder, a volatile agent and the copper anode slime, stirring uniformly, granulating, and obtaining coal-mixed anode slime particles; calcining the coal-mixed anode slime particles, and passing generated flue gas into a gas-solid spiral separator for dust collection, and recovering calcined capture powder; mixing an aqueous sodium hydroxide solution and the calcined capture powder, stirring uniformly, then heating the slurry, and performing solid-liquid separation after the heating is completed, and obtaining a liquid, which is a tellurium-rich liquid; irradiating the tellurium-rich liquid with a low-temperature plasma, and obtaining a tellurium-rich activated liquid; adding sodium sulfite into the tellurium-rich activated liquid, stirring, and performing solid-liquid separation, and washing the obtained solid with clean water, and then drying to obtain a tellurium product. The preparation process is simple, the required raw materials are conventional materials, tellurium is efficiently recovered and extracted from the copper anode slime through early-stage reasonable dosing, carbothermal chlorination, low-temperature plasma activation and reduction reaction, and the prepared product can reach a tellurium content of 94.36% at most.

Description

A method for rapid separation and recovery of tellurium from copper anode mud Technical Field

[0001] This invention belongs to the field of solid waste resource utilization, and in particular relates to a method for rapidly separating and recovering tellurium from copper anode mud. Background Technology

[0002] Copper anode sludge, an inevitable byproduct of copper electrolytic refining, contains various valuable metallic elements, but also poses significant environmental hazards. During copper electrolytic refining, the anode copper plate dissolves in the electrolytic cell, and impurities such as silver, gold, selenium, and tellurium gradually accumulate in the anode sludge. While copper anode sludge is rich in metallic elements, its treatment process is accompanied by serious environmental problems. Therefore, how to scientifically and efficiently treat copper anode sludge to achieve effective resource recovery and sustainable environmental development has become a current research challenge. The treatment of copper anode sludge generates large amounts of harmful gases such as smoke, nitrogen oxides, and sulfur dioxide. If the waste residue and waste generated during the treatment process are not properly treated and are indiscriminately dumped, they will pollute the soil, affect the ecological balance, and even lead to the collapse of the ecosystem.

[0003] Tellurium is a rare and valuable metallic element with wide applications in semiconductors, solar cells, and metallurgy. Rapidly separating and recovering tellurium from copper anode sludge not only enables efficient resource utilization but also reduces the exploitation of natural resources, contributing to resource conservation and environmental protection. Simultaneously, recovering tellurium from copper anode sludge can alleviate my country's tellurium resource shortage to some extent, reducing dependence on external supplies and thus safeguarding national security and economic development. With continuous technological advancements and increasingly stringent environmental requirements, copper anode sludge treatment and tellurium recovery technologies need constant optimization and upgrading to provide strong support for the sustainable development of related industries. Strengthening research and application of copper anode sludge treatment and tellurium recovery technologies is a concrete practice of the circular economy concept. Summary of the Invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method that is simple to prepare and can quickly and efficiently separate, recover and extract tellurium from copper anode mud.

[0005] The technical problem that this invention also aims to solve is to provide a tellurium product with a tellurium content as high as 84.24-94.36% obtained by the separation method described above.

[0006] Technical Solution: To solve the above-mentioned technical problems, the present invention provides a method for rapidly separating and recovering tellurium from copper anode mud, comprising the following steps:

[0007] (1) Mix coal powder, volatile agent and copper anode mud, stir evenly, granulate to obtain coal-mixed anode mud particles;

[0008] (2) The coal-mixed anode mud particles are calcined, and the flue gas generated during the calcination process is passed into a gas-solid spiral separator for dust collection. The recovered flue gas dust is the calcination collection powder.

[0009] (3) Mix the caustic soda aqueous solution and calcined collecting powder, stir evenly, then heat the slurry, and after heating, perform solid-liquid separation. The resulting liquid is the tellurium-rich liquid.

[0010] (4) The tellurium-rich liquid was subjected to low-temperature plasma irradiation to obtain a tellurium-rich activated liquid;

[0011] (5) Add sodium sulfite to the tellurium-rich activation solution, stir for 1 to 4 hours, separate the solid and liquid, rinse the obtained solid with water, and then dry it to obtain the tellurium product.

[0012] The volatile agent mentioned in step (1) is any one of ammonium chloride, calcium chloride, and magnesium chloride.

[0013] In step (1), the mass ratio of pulverized coal, volatile agent and copper anode mud is 25-75:25-45:100.

[0014] In step (2), the calcination temperature is 400-600℃ and the calcination time is 1-5 hours.

[0015] In step (3), the concentration of the caustic soda aqueous solution is 2-5M, and the liquid-solid ratio of the caustic soda aqueous solution to the calcined trapping powder is 1.5-7.5:1mL / g.

[0016] The heating temperature in step (3) is 80-120℃.

[0017] In step (4), the low-temperature plasma irradiation time is 0.5 to 4.5 hours, the low-temperature plasma voltage is 5 to 75 kV, and the low-temperature plasma atmosphere is any one of air, oxygen, or ozone.

[0018] In step (5), the molar amount of sodium sulfite is 4 to 8 times the molar amount of tellurium in the tellurium-rich activation solution.

[0019] The present invention also includes tellurium products prepared by the method.

[0020] The tellurium content of the tellurium product is 84.24% to 94.36%.

[0021] The reaction mechanism of this invention involves mixing coal powder, a volatile agent, and copper anode slime. During the stirring and granulation process, the volatile agent dissolves, and the three materials are thoroughly mixed. The aluminosilicate minerals in the coal powder adsorb chloride ions and cations from the volatile agent and adsorb and eliminate hydrogen ions from the copper anode slime. The coal-mixed anode slime particles are then calcined. During calcination, carbon in the coal powder undergoes pyrolysis and oxidation, releasing a large amount of heat. Under high-temperature conditions, the silicates and aluminosilicate minerals in the coal powder can adsorb and stabilize elements such as copper, zinc, lead, silver, and palladium, thus creating a slag-forming effect. The cations in the volatile agent enhance the adsorption and stabilization effect of the silicates and aluminosilicate minerals in the coal powder on elements such as copper, zinc, lead, silver, and palladium through ion exchange and lattice defects. Simultaneously, under high-temperature conditions, elements such as tellurium, selenium, gold, platinum, and iron in the coal-mixed anode slime particles combine with chloride ions in the volatile agent on the surface of the coal powder particles and pyrolysis products to form chlorides. These chlorides then volatilize under carbothermic chlorination and enter the flue gas, where they are captured and recovered when the flue gas enters the gas-solid spiral separator. The high-temperature gases released from the pyrolysis and oxidation of carbon in pulverized coal can activate copper anode mud, enhancing the release of elements such as tellurium, selenium, gold, platinum, and iron. This promotes the combination and continuous release of these elements with chlorine. Mixing caustic soda solution with calcined trapping powder during heating allows iron to combine with hydroxide ions to form a precipitate, while ferric hydroxide can adsorb some of the hydroxide-complexed platinum, gold, and selenium elements, creating a co-precipitation effect. Low-temperature plasma irradiation of tellurium-rich solutions enhances the electrophilicity of tellurium, thereby improving the selective reaction between tellurium and reducing agents. Adding sodium sulfite to tellurium-rich solutions reduces tellurium, forming elemental tellurium material.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following advantages: The preparation process of the present invention is simple, the raw materials required are conventional materials, and there are many ways to obtain them. Through reasonable pre-processing, carbothermic chlorination, low-temperature plasma activation and reduction reaction, tellurium is efficiently recovered and extracted from copper anode mud. The tellurium content in the prepared product can reach up to 94.36%. Attached Figure Description

[0023] Figure 1 is a flowchart of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Pulverized coal: The pulverized coal was taken from Zhangji Coal Mine of Huainan Mining (Group) Co., Ltd., and mainly consisted of 89.14% C. daf 5.08% H daf 2.87% O daf 1.62% S daf 1.29% N daf composition;

[0026] Copper anode slime: The copper anode slime was obtained from Yunnan Copper Co., Ltd. XRF analysis of the elemental composition of the copper anode slime is as follows: 26.72% O, 20.46% Cu, 7.58% Pb, 7.02% Se, 5.54% S, 5.32% Ag, 4.47% As, 4.08% Sb, 4.02% Sn, 3.75% Ba, 2.64% Te, 1.75% Bi, 1.51% Cl, 1.12% Ni, 0.82% Zn, 0.24% Mg, 0.17% Si, 0.15% Au, and other components (unavoidable loss on ignition).

[0027] Ammonium chloride: purity AR (99.5%), CAS number: 12125-02-9, molecular formula: NH4Cl, MDL number: MFCD00143604, PubChem number: 25517;

[0028] Calcium chloride: purity 97.0%, CAS number: 10043-52-4, molecular formula: CaCl2, MDL number: MFCD00010903, PubChem number: 5284359;

[0029] Magnesium chloride: purity 99%, CAS number: 7786-30-3, molecular formula: MgCl2, MDL number: MFCD00011106, PubChem number: 5360315;

[0030] Sodium sulfite: Purity AR (98.0%), CAS No.: 7757-83-7, Molecular Formula: Na2SO3, MDL No.: MFCD00003503, PubChem No.: 24437.

[0031] Example 1: Effect of the mass ratio of pulverized coal, volatile agent, and copper anode slime on the tellurium content of the prepared product.

[0032] According to the mass ratios of 17.5:25:100, 20:25:100, 22.5:25:100, 25:17.5:100, 25:20:100, 25:22.5:100, 25:25:100, 50:25:100, 75:25:100, 25:35:100, 50:35:100, and 75:35:10 Coal powder, volatile organic compound (VOC), and copper anode slime were mixed in ratios of 0, 25:45:100, 50:45:100, 75:45:100, 75:50:100, 75:55:100, 75:60:100, 80:45:100, 85:45:100, and 90:45:100. The mixture was stirred until homogeneous, then granulated to obtain coal-mixed anode slime granules, where ammonium chloride was the VOC. The coal-mixed anode slime granules were then introduced into a calcining furnace for calcination. The flue gas generated during calcination was passed through a gas-solid spiral separator (Changchun Hongmao Technology Co., Ltd., model: FX-350) for dust collection. The recovered flue gas dust was the calcination collection powder. The calcination temperature was 400℃, and the calcination time was 1 hour. A 2M caustic soda aqueous solution was prepared by dissolving sodium hydroxide in water. A caustic soda aqueous solution and calcined trapping powder were mixed at a liquid-to-solid ratio of 1.5:1 mL / g and stirred until homogeneous. The slurry was then heated, followed by solid-liquid separation. The resulting liquid was the tellurium-rich solution, with a heating temperature of 80℃. The tellurium-rich solution was then subjected to low-temperature plasma irradiation for 0.5 hours, with an irradiation voltage of 5 kV and an air atmosphere. Sodium sulfite was added to the tellurium-rich activated solution, with a molar amount of sodium sulfite equal to four times the molar amount of tellurium in the activated solution. The mixture was stirred for one hour, followed by solid-liquid separation using a plate and frame filter press. The resulting solid was washed with water and dried to obtain the tellurium product.

[0033] Tellurium content detection of tellurium products: The tellurium content in the tellurium products prepared in this invention was detected and determined in accordance with the "Tellurium Chemical Analysis Methods Part 9: Determination of Tellurium Content by Potassium Dichromate-Ferrous Ammonium Sulfate Titration Method" (YS-T 227.9-2010).

[0034] The test results of this embodiment are shown in Table 1.

[0035] Table 1. Effect of the mass ratio of pulverized coal, volatile agent, and copper anode slime on the tellurium content of the prepared product.

[0036]

[0037]

[0038] As shown in Table 1, when the mass ratio of pulverized coal, volatile agent, and copper anode slime is less than 25:25:100 (such as in Table 1, when the mass ratio of pulverized coal, volatile agent, and copper anode slime is 22.5:25:100, 20:25:100, 17.5:25:100, 25:22.5:100, 25:20:100, 25:17.5:100, and even lower ratios not listed in Table 1), less pulverized coal and volatile agent are added, resulting in an imbalance in the material composition. Consequently, the tellurium content of the prepared product decreases significantly as the mass ratio of pulverized coal, volatile agent, and copper anode slime decreases. When the mass ratio of pulverized coal, volatile agent, and copper anode slime is 25–75:25–45:100 (as shown in Table 1, where the mass ratios are 25:25:100, 50:25:100, 75:25:100, 25:35:100, 50:35:100, 75:35:100, 25:45:100, 50:45:100, and 75:45:100), the pulverized coal, volatile agent, and copper anode slime are mixed. During the stirring and granulation process, the volatile agent dissolves, and the three materials are thoroughly mixed. The aluminosilicate minerals in the pulverized coal adsorb chloride ions and cations from the volatile agent and adsorb and eliminate hydrogen ions from the copper anode slime. Ultimately, the tellurium content of the prepared products is greater than 84%. When the mass ratio of pulverized coal, volatile agent, and copper anode slime is greater than 75:45:100 (as shown in Table 1, where the mass ratios are 75:50:100, 75:55:100, 75:60:100, 80:45:100, 85:45:100, 90:45:100, and higher ratios not listed in Table 1), excessive addition of pulverized coal and volatile agent leads to poorer calcination results in a significant decrease in the tellurium content of the prepared product as the mass ratio of pulverized coal, volatile agent, and copper anode slime further increases. Therefore, considering both efficiency and cost, a mass ratio of pulverized coal, volatile agent, and copper anode slime of 25–75:25–45:100 is most beneficial for increasing the tellurium content of the prepared product.

[0039] Example 2: Effect of calcination temperature on the tellurium content of the prepared product

[0040] Coal powder, volatile agent, and copper anode mud were mixed in a mass ratio of 75:45:100, stirred evenly, and granulated to obtain coal-mixed anode mud granules, wherein the volatile agent was calcium chloride. The coal-mixed anode mud granules were introduced into a calcining furnace for calcination. The flue gas generated during calcination was passed through a gas-solid spiral separator (Changchun Hongmao Technology Co., Ltd., model: FX-350) for dust collection. The recovered flue gas dust was the calcination collecting powder. The calcination temperatures were 325℃, 350℃, 375℃, 400℃, 500℃, 600℃, 625℃, 650℃, and 675℃, and the calcination time was 3 hours. A 3.5M caustic soda aqueous solution was prepared by dissolving sodium hydroxide in water. The caustic soda aqueous solution and the calcination collecting powder were mixed in a liquid-solid ratio of 4.5:1 mL / g and stirred evenly. The slurry was then heated, and after heating, solid-liquid separation was performed. The resulting liquid was the tellurium-rich solution, and the heating temperature was 100℃. Tellurium-rich liquid was irradiated with low-temperature plasma for 2.5 hours to obtain an activated tellurium-rich solution. The plasma irradiation voltage was 40 kV, and the atmosphere was oxygen. Sodium sulfite was added to the activated tellurium-rich solution, with the molar amount of sodium sulfite being 6 times the molar amount of tellurium in the activated solution. The mixture was stirred for 2.5 hours, and then the solid and liquid were separated using a plate and frame filter press. The obtained solid was washed with water and dried to obtain the tellurium product.

[0041] The tellurium content of the tellurium product was tested in the same way as in Example 1. The test results of this example are shown in Table 2.

[0042] Table 2 Effect of calcination temperature on tellurium content of the prepared products

[0043] Calcination temperature and tellurium content error percentage: 325℃ 76.58±0.1%; 350℃ 81.36±0.2%; 375℃ 85.01±0.1%; 400℃ 88.62±0.1%; 500℃ 90.14±0.1%; 600℃ 90.87±0.1%; 625℃ 86.79±0.1%; 650℃ 82.26±0.1%; 675℃ 79.73±0.1%. surface

[0044] As shown in Table 2, when the calcination temperature is below 400℃ (as shown in Table 2, calcination temperatures = 375℃, 350℃, 325℃, and even lower values ​​not listed in Table 2), the calcination temperature is low, and the material reaction is insufficient, resulting in a significant decrease in the tellurium content of the prepared product as the calcination temperature decreases. When the calcination temperature is between 400℃ and 600℃ (as shown in Table 2, calcination temperatures = 400℃, 500℃, 600℃), the coal-mixed anode mud particles are calcined. During the calcination process, the carbon in the coal powder undergoes pyrolysis and oxidation reactions, releasing a large amount of heat. Under high-temperature conditions, silicate and aluminosilicate minerals in the coal powder can adsorb and stabilize elements such as copper, zinc, lead, silver, and palladium, thereby forming a slag-forming effect. The cations in the volatile agent enhance the adsorption and stabilization effect of silicate and aluminosilicate minerals in the coal powder on elements such as copper, zinc, lead, silver, and palladium through ion exchange and lattice defects. Simultaneously, under high-temperature conditions, elements such as tellurium, selenium, gold, platinum, and iron in the coal-mixed anode mud combine with chloride ions in the volatile agent on the surface of coal powder particles and coal pyrolysis products to form chlorides. These chlorides then volatilize under carbothermic chlorination and enter the flue gas, where they are captured and recovered when the flue gas enters the gas-solid spiral separator. The high-temperature gas released from the pyrolysis and oxidation of carbon in the coal powder can activate the copper anode mud, enhancing the release of elements such as tellurium, selenium, gold, platinum, and iron, thereby promoting the combination and continuous release of these elements with chlorine. When the calcination temperature exceeds 600℃ (as shown in Table 2, calcination temperatures = 625℃, 650℃, 675℃, and higher values ​​not listed in Table 2), the calcination temperature is too high, the material cokes too quickly, and volatile impurities increase, resulting in a significant decrease in the tellurium content of the prepared product as the calcination temperature further increases. Therefore, considering both benefits and costs, a calcination temperature of 400–600°C is most conducive to increasing the tellurium content of the prepared product.

[0045] Example 3: Effect of Low-Temperature Plasma Irradiation Time on Tellurium Content of the Prepared Product

[0046] Coal powder, volatile agent, and copper anode mud were mixed in a mass ratio of 75:45:100, stirred evenly, and granulated to obtain coal-mixed anode mud granules, wherein the volatile agent was magnesium chloride. The coal-mixed anode mud granules were introduced into a calcining furnace for calcination. The flue gas generated during calcination was passed through a gas-solid spiral separator (Changchun Hongmao Technology Co., Ltd., model: FX-350) for dust collection. The recovered flue gas dust was the calcination collecting powder. The calcination temperature was 600℃, and the calcination time was 5 hours. Sodium hydroxide was dissolved in water to prepare a 5M caustic soda aqueous solution. The caustic soda aqueous solution and the calcination collecting powder were mixed in a liquid-solid ratio of 7.5:1 mL / g and stirred evenly. The slurry was then heated, and after heating, solid-liquid separation was performed. The resulting liquid was the tellurium-rich solution, and the heating temperature was 120℃. Tellurium-rich liquid was irradiated with low-temperature plasma to obtain tellurium-rich activated liquid. The irradiation times were 0.25 hours, 0.3 hours, 0.4 hours, 0.5 hours, 2.5 hours, 4.5 hours, 4.75 hours, 5 hours, and 5.25 hours. The low-temperature plasma voltage was 75 kV, and the atmosphere was ozone. Sodium sulfite was added to the tellurium-rich activated liquid, with the molar amount of sodium sulfite being 8 times the molar amount of tellurium in the activated liquid. The mixture was stirred for 4 hours, and then the solid and liquid were separated using a plate and frame filter press. The obtained solid was washed with water and dried to obtain the tellurium product.

[0047] The tellurium content of the product was tested in the same way as in Example 1. The test results of this example are shown in Table 3.

[0048] Table 3 Effect of low-temperature plasma irradiation time on tellurium content of the prepared products

[0049]

[0050]

[0051] As shown in Table 3, when the low-temperature plasma irradiation time is less than 0.5 hours (as shown in Table 3, low-temperature plasma irradiation time = 0.4 hours, 0.3 hours, 0.25 hours, and even lower values ​​not listed in Table 3), the low-temperature plasma irradiation time is relatively short, resulting in insufficient activation of the tellurium-rich solution. Consequently, the tellurium content of the prepared product decreases significantly as the low-temperature plasma irradiation time decreases. When the low-temperature plasma irradiation time is equal to 0.5–4.5 hours (as shown in Table 3, low-temperature plasma irradiation time = 0.5 hours, 2.5 hours, and 4.5 hours), low-temperature plasma irradiation of the tellurium-rich solution can enhance the electrophilicity of tellurium, thereby improving the selective reaction between tellurium and the reducing agent. When the low-temperature plasma irradiation time exceeds 4.5 hours (as shown in Table 3, where the irradiation time is 4.75 hours, 5 hours, 5.25 hours, and higher values ​​not listed in Table 3), the irradiation time is too long, leading to excessive activation of the tellurium-rich solution and further oxidation of some tellurium. This results in a significant decrease in the tellurium content of the prepared product as the irradiation time increases further. Therefore, considering both benefits and costs, a low-temperature plasma irradiation time of 0.5–4.5 hours is most advantageous for improving the tellurium content of the prepared product.

Claims

1. A method for rapidly separating and recovering tellurium from copper anode mud, characterized in that, Includes the following steps: (1) Mix coal powder, volatile agent and copper anode mud, stir evenly, granulate to obtain coal-mixed anode mud particles; (2) Calcine the coal-mixed anode mud particles, and pass the flue gas generated during the calcination process into a gas-solid spiral separator for dust collection. The flue gas dust obtained is the calcination collection powder; (3) Mix caustic soda aqueous solution and calcination collection powder, stir evenly, and then heat the slurry. After heating, perform solid-liquid separation, and the obtained liquid is the tellurium-rich liquid; (4) Irradiate the tellurium-rich liquid with low-temperature plasma to obtain tellurium-rich activated liquid; (5) Add sodium sulfite to the tellurium-rich activated liquid, stir for 1 to 4 hours, separate the solid and liquid, wash the obtained solid with water, and then dry to obtain tellurium product; The volatile agent mentioned in step (1) is any one of ammonium chloride, calcium chloride and magnesium chloride.

2. The method for rapidly separating and recovering tellurium from copper anode mud according to claim 1, characterized in that, The mass ratio of pulverized coal, volatile agent and copper anode mud in step (1) is 25~75:25~45:

100.

3. The method for rapidly separating and recovering tellurium from copper anode mud according to claim 1, characterized in that, In step (2), the calcination temperature is 400~600℃ and the calcination time is 1~5 hours.

4. The method for rapidly separating and recovering tellurium from copper anode mud according to claim 1, characterized in that, The concentration of the caustic soda aqueous solution in step (3) is 2~5M, and the liquid-solid ratio of the caustic soda aqueous solution to the calcined trapping powder is 1.5~7.5:1mL / g.

5. The method for rapidly separating and recovering tellurium from copper anode mud according to claim 1, characterized in that, The heating temperature in step (3) is 80~120℃.

6. The method for rapidly separating and recovering tellurium from copper anode mud according to claim 1, characterized in that, The low-temperature plasma irradiation time in step (4) is 0.5 to 4.5 hours, the low-temperature plasma voltage is 5 to 75 kV, and the low-temperature plasma atmosphere is any one of air, oxygen, or ozone.

7. The method for rapidly separating and recovering tellurium from copper anode mud according to claim 1, characterized in that, The molar amount of sodium sulfite mentioned in step (5) is 4 to 8 times the molar amount of tellurium in the tellurium-rich activation solution.

Images