Method for comprehensively recovering tellurium, copper, gold, silver and selenium in tellurium-copper slag

Abstract

The invention relates to a method for comprehensively recovering tellurium, copper, gold, silver and selenium in tellurium copper slag, which comprises the following steps: (1) ball-milling tellurium copper slag and water to obtain ball-milled slurry; (2) adding caustic soda liquid into the ball-milled slurry, stirring for reaction, and filtering to obtain a leaching solution and leaching residues; (3) adding water into the leaching residues, slurrying, adding concentrated sulfuric acid, reacting, and filtering to obtain gold and silver residues and filtrate A; (4) evaporating, concentrating and filtering the filtrate A to obtain copper sulfate; (5) heating the leachate, adding a saturated sodium hydrosulfide solution, transforming, and filtering to obtain filtrate C and filter residues A; (6) adding concentrated sulfuric acid into the filtrate C for neutralization, stirring until the tellurium content is lower than 200mg / L, and filtering to obtain tellurium powder and filtrate D; and (7) heating the filtrate D, adding a saturated sodium sulfite solution, adjusting the pH value, filtering after reaction, discharging sewage from the obtained filtrate E, and obtaining a filter residue B which is crude selenium. The method has the characteristics of low energy consumption and material consumption, high production efficiency, low operation cost and high valuable metal recovery rate.

Description

Technical Field

[0001] The present invention relates to the field of comprehensive resource recovery in the copper smelting industry, and particularly to a method for comprehensively recovering tellurium, copper, gold, silver, and selenium from tellurium copper slag. Background Art

[0002] The level of comprehensive utilization of non-ferrous smelting resources is an important indicator for judging the smelting technology level. The tellurium copper slag produced in the process of treating copper smelting anode slime contains valuable metals such as copper, tellurium, selenium, gold, and silver. At present, the main processes for treating tellurium copper slag include sulfation roasting, caustic soda roasting, oxidative alkali leaching, oxidative acid leaching, etc. These processes mainly focus on the resource recovery of tellurium and copper in tellurium copper slag, and do not treat valuable elements such as selenium, gold, and silver in it. For the treatment of tellurium copper slag by sulfation roasting and caustic soda roasting processes, it is difficult to purify impurities, difficult to control product quality, and both investment and low-altitude pollution are relatively large, causing serious environmental pollution. Although the acid leaching for copper removal - alkali leaching process has less environmental pollution, the operation and production processes are complex, the process flow is long, and the recovery rate of valuable metals is low. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for comprehensively recovering tellurium, copper, gold, silver, and selenium from tellurium copper slag with low energy consumption, low material consumption, high production efficiency, low operating cost, and high recovery rate of valuable metals.

[0004] To solve the above problems, a method for comprehensively recovering tellurium, copper, gold, silver, and selenium from tellurium copper slag according to the present invention includes the following steps: ⑴ Ball-mill tellurium copper slag and water in a wet ball mill at a liquid-solid ratio (L / kg) of 1:1 to 2:3 to obtain a ball-milled slurry; ⑵ Add liquid caustic soda with a mass concentration of 30% - 50% to the ball-milled slurry, such that the mass ratio of sodium hydroxide in the liquid caustic soda to tellurium copper slag is 1:1 to 2:3, and maintain the mass ratio of water to tellurium copper slag at 3:1 to 10:1 by adding water. During this period, introduce saturated steam at a temperature above 100°C and compressed air at a pressure of 0.1 - 0.6 MPa to ensure that the temperature in the reaction system is maintained above 85°C. Stir and react for 0.5 - 3 hours and then filter to obtain a leachate and a leach residue; ⑶ Slurry the leach residue with water at a liquid-solid ratio (L / kg) of 10:1 to 20:1, then add concentrated sulfuric acid to make the volume concentration of sulfuric acid in the reaction tank 30% - 50%. After mixing, stirring and reacting, filter to obtain a gold-silver residue and filtrate A respectively; the gold-silver residue is returned to the copper smelting precious metal recovery system to recover gold and silver; ⑷ Evaporate and concentrate filtrate A. After the liquid volume is reduced by half, carry out cooling crystallization. After the temperature drops to 40 - 50°C, filter to obtain copper sulfate, and return filtrate B to step ⑶; (5) Heat the leaching solution to above 90°C, slowly add a saturated sodium hydrosulfide solution, with the molar ratio of tellurium to the saturated sodium hydrosulfide solution in the leaching solution being 1:1. After reacting for 30 to 60 minutes or more and undergoing transformation, filter to obtain filtrate C and filter residue A respectively; return the filter residue A to step (1); (6) After adding concentrated sulfuric acid to the filtrate C to neutralize the pH to 5 - 6, stir for 30 to 60 minutes or more. After the pH value is stable and the tellurium content in the solution is lower than 200 mg / L, filter to obtain tellurium powder and filtrate D; (7) After heating the filtrate D to above 70°C, add a saturated sodium sulfite solution in an amount of 1 to 3 times the molar content of tellurium in the filtrate D. Use dilute sulfuric acid or liquid alkali to adjust the pH value of the solution to be maintained at 2 - 3. After reacting for 4 to 8 hours, filter. The obtained filtrate E is discharged as sewage, and the filter residue B is crude selenium.

[0005] In the above step (1), the tellurium - copper slag is a tellurium - copper slag with a tellurium content greater than 3%.

[0006] In the above step (1), the particle size of the solid particles in the ball - milled slurry is below 200 µm.

[0007] In the above step (3), the conditions for the mixing and stirring reaction refer to a temperature above 70°C and a reaction time of 0.5 to 2 hours.

[0008] The present invention has the following advantages compared with the prior art: 1. Since the present invention organically combines complex chemical reactions and physical separation processes, a relatively simplified and efficient technological process is formed. Compared with the traditional acid leaching for copper removal - alkali leaching treatment process, through the reasonable connection of steps such as ball - milling, leaching, filtration, evaporation concentration, crystallization, sulfide conversion, acidification reduction, etc., the present invention avoids unnecessary processes and complex operations, reduces energy consumption and material consumption during the production process, improves production efficiency, and reduces equipment investment and operating costs.

[0009] 2. The present invention realizes the efficient recovery of valuable metals, selenium, silver, copper, etc. through step - by - step implementation, and the produced products can all be sold as current standard products. The yield and productivity are relatively high. For example, the purity of the crude selenium product reaches above 99.5%, the purity of the tellurium product reaches above 99%, and the gold and silver contents in the precious metal slag after gold and silver enrichment are also as high as 0.25% and 7% or more respectively. This shows that the present invention can effectively improve the quality of the recovered products, meet the market demand for high - purity metal products, and is conducive to improving the market competitiveness of enterprises.

[0010] 3. The present invention is applicable to treating tellurium - copper slag with a tellurium content greater than 3%, and has strong adaptability to raw materials. Regardless of how the contents of valuable metals such as tellurium, copper, selenium, gold, and silver in the tellurium - copper slag change, by adjusting the reaction conditions and process parameters, good recovery effects can be achieved, which helps to improve the overall level of smelting technology and reduce resource waste. Brief Description of the Drawings

[0011] The following further describes in detail the specific embodiments of the present invention in conjunction with the drawings.

[0012] Figure 1 It is the process flow chart of the present invention. Specific Embodiments

[0013] As Figure 1 shown, a method for comprehensively recovering tellurium, copper, gold, silver, and selenium from tellurium copper slag includes the following steps: ⑴ Ball-mill tellurium copper slag and water in a wet ball mill at a liquid-solid ratio (L / kg) of 1:1 to 2:3 to obtain a ball-milled slurry.

[0014] Among them: The tellurium copper slag is a copper telluride slag with a tellurium content greater than 3%. The particle size of the solid particles in the ball-milled slurry is below 200 µm.

[0015] ⑵ Add liquid caustic soda with a mass concentration of 30% - 50% to the ball-milled slurry, so that the mass ratio (kg / kg) of sodium hydroxide in the liquid caustic soda to the tellurium copper slag is 1:1 to 2:3, and maintain the mass ratio (kg / kg) of water to the tellurium copper slag at 3:1 to 10:1 by adding water. During this period, inject saturated steam with a temperature above 100 °C and compressed air with a pressure of 0.1 - 0.6 MPa to ensure that the temperature in the reaction system remains above 85 °C. After stirring and reacting for 0.5 - 3 hours, filter to obtain the leaching solution and the leaching residue.

[0016] ⑶ Slurry the leaching residue with water at a liquid-solid ratio (L / kg) of 10:1 to 20:1, and then add concentrated sulfuric acid to make the volume concentration of sulfuric acid in the reaction tank 30% - 50%. After mixing and stirring at a temperature above 70 °C for 0.5 - 2 hours, filter to obtain the gold-silver residue and filtrate A respectively; the gold-silver residue is returned to the copper smelting precious metal recovery system to recover gold and silver.

[0017] ⑷ Heat filtrate A to above 90 °C for evaporation and concentration. After the liquid volume is reduced by half, cool for crystallization. After the temperature drops to 40 - 50 °C, filter to obtain copper sulfate, and return filtrate B to step ⑶.

[0018] ⑸ Heat the leaching solution to above 90 °C, and slowly add a saturated sodium hydrosulfide solution. The molar ratio of tellurium in the leaching solution to the saturated sodium hydrosulfide solution is 1:1. After reacting for more than 30 - 60 minutes for transformation, filter to obtain filtrate C and filter residue A respectively; filter residue A is returned to step ⑴.

[0019] ⑹ Add concentrated sulfuric acid to filtrate C to neutralize the pH to 5 - 6, stir for more than 30 - 60 minutes until the pH value is stable and the tellurium content in the solution is lower than 200 mg / L, and then filter to obtain tellurium powder and filtrate D.

[0020] ⑺ After the filtrate D is heated to above 70 °C, a saturated sodium sulfite solution is added in an amount of 1 to 3 times the molar content of tellurium in the filtrate D, and the pH value of the solution is adjusted to 2 to 3 with dilute sulfuric acid or liquid alkali. After reacting for 4 to 8 hours, filtration is carried out. The obtained filtrate E is discharged as sewage, and the filter residue B is crude selenium.

[0021] Reaction principle of the present invention: Leaching process of tellurium copper slag: 2CuTe + 2NaOH + 3.5O 2 = 2NaTeO 3 + 2CuO + H 2 O SeO 2 + 2NaOH = Na 2 SeO 3 + H 2 O Acid leaching process of leaching residue CuO + H 2 SO 4 = CuSO4 + H 2 O Sulfide conversion process Na 2 TeO 3 + 3NaHS = Na 2 TeS 3 + 3NaOH Tellurium precipitation process with sulfuric acid 2Na 2 TeS 3 + 8NaOH = 2Te + Na 2 SO 4 + 5Na 2 S + 4H 2 O Selenium reduction process Na 2 SeO 2 + 2Na 2 SO 2 = Se + 3Na 2 SO 4 Example 1 A method for comprehensively recovering tellurium, copper, gold, silver, and selenium from tellurium copper slag, comprising the following steps: ⑴ In a wet ball mill, 1 kg of tellurium copper slag with a particle size not greater than 20 mm (as shown in Table 1) is ball milled with water at a liquid-solid ratio (L / kg) of 1:1, obtaining a ball mill slurry with a solid particle size of less than 200 µm.

[0022] Table 1 Composition table of tellurium copper slag ⑵ Add liquid caustic with a mass concentration of 50% to the ball-milled slurry, so that the mass ratio (kg / kg) of sodium hydroxide to tellurium-copper slag in the liquid caustic is 1:2, and maintain the mass ratio (kg / kg) of water to tellurium-copper slag at 5:1 by adding water. During this period, saturated steam with a temperature above 100 °C and compressed air with a pressure of 0.3 MPa are introduced to ensure that the temperature in the reaction system remains at 90 °C. After stirring and reacting for 3 hours, filter to obtain 5.3 L of leaching solution and 554 g of leaching residue.

[0023] ⑶ Slurry the leaching residue with water at a liquid-solid ratio (L / kg) of 20:1, and then add concentrated sulfuric acid to make the volume concentration of sulfuric acid in the reaction tank 30%. Mix and stir at a temperature above 70 °C for 2 hours and then filter to obtain 4.87 g of gold-silver residue and 12 L of filtrate A respectively; the gold-silver residue is returned to the copper smelting precious metal recovery system to recover gold and silver.

[0024] ⑷ Heat filtrate A in a concentration reactor to above 90 °C for evaporation and concentration. After the liquid volume is reduced by half, cool down for crystallization. When the temperature drops to 40 °C, discharge the crystals and solution in the concentration kettle together and filter with a filter press to obtain 334 g of copper sulfate, and return filtrate B to step ⑶. The copper sulfate is sold externally or further refined to recover copper.

[0025] ⑸ Heat the leaching solution to above 90 °C and slowly add saturated sodium hydrosulfide solution. The molar ratio of tellurium in the leaching solution to the saturated sodium hydrosulfide solution is 1:1. After reacting and transforming for more than 30 minutes, filter to obtain 5.5 L of filtrate C and filter residue A respectively; filter residue A is returned to step ⑴.

[0026] ⑹ Add concentrated sulfuric acid to filtrate C to neutralize the pH to 5, stir for more than 30 minutes until the pH value is stable and the tellurium content in the solution is lower than 200 mg / L, and then filter to obtain 285 g of tellurium powder and 5.48 L of filtrate D.

[0027] ⑺ Heat filtrate D to above 70 °C, and add saturated sodium sulfite solution according to 1 - 3 times the molar content of tellurium in filtrate D. Adjust the pH value of the solution to 3 with dilute sulfuric acid or liquid caustic. After reacting for 6 hours, filter. The obtained filtrate E is discharged as sewage, and 147 g of filter residue B is crude selenium.

[0028] The component tables of each recovered product are shown in Table 2.

[0029] Table 2 Component Tables of Recovered Products Example 2 A method for comprehensively recovering tellurium, copper, gold, silver, and selenium from tellurium-copper slag, comprising the following steps: ⑴ In a wet ball mill, 1 kg of tellurium copper slag with a particle size not greater than 20 mm (as shown in Table 3) is ball milled with water at a liquid-solid ratio (L / kg) of 1:1, obtaining a ball mill slurry with a solid particle size below 200 µm.

[0030] Table 3 Composition Table of Tellurium Copper Slag ⑵ Add liquid caustic soda with a mass concentration of 30% to the ball mill slurry, so that the mass ratio (kg / kg) of sodium hydroxide in the liquid caustic soda to the tellurium copper slag is 1:1, and maintain the mass ratio (kg / kg) of water to the tellurium copper slag at 3:1 by adding water. During this period, saturated steam with a temperature above 100 °C and compressed air with a pressure of 0.1 MPa are introduced to ensure that the temperature in the reaction system remains at 93 °C. After stirring and reacting for 2.5 hours, filter to obtain 3.25 L of leaching solution and 586 g of leaching residue.

[0031] ⑶ The leaching residue is slurried with water at a liquid-solid ratio (L / kg) of 10:1, and then concentrated sulfuric acid is added to make the volume concentration of sulfuric acid in the reaction tank 45%. After mixing and stirring at a temperature above 80 °C for 1 hour, filter to obtain 5.68 g of gold-silver residue and 6 L of filtrate A respectively; the gold-silver residue is returned to the copper smelting precious metal recovery system to recover gold and silver.

[0032] ⑷ Filtrate A is heated to above 93 °C in a concentration reaction kettle for evaporation and concentration. After the liquid volume is reduced by half, cooling crystallization is carried out. When the temperature drops to 45 °C, the crystallized substances and the solution in the concentration kettle are discharged together and filtered with a filter press to obtain 325 g of copper sulfate, and filtrate B is returned to step ⑶. The copper sulfate is sold externally or further refined to recover copper.

[0033] ⑸ The leaching solution is heated to above 93 °C, and saturated sodium hydrosulfide solution is slowly added. The molar ratio of tellurium in the leaching solution to the saturated sodium hydrosulfide solution is 1:1. After reacting for more than 60 minutes for transformation, filter to obtain 3.3 L of filtrate C and filter residue A respectively; filter residue A is returned to step ⑴.

[0034] ⑹ After adding concentrated sulfuric acid to filtrate C to neutralize the pH to 5.6, stir for more than 60 minutes until the pH value is stable and the tellurium content in the solution is lower than 200 mg / L, and then filter to obtain 258 g of tellurium powder and 3.84 L of filtrate D.

[0035] ⑺ After heating filtrate D to above 70 °C, saturated sodium sulfite solution is added according to 1 - 3 times the molar content of tellurium in filtrate D, and the pH value of the solution is adjusted to 2.5 with dilute sulfuric acid or liquid caustic soda. After reacting for 8 hours, filter. The obtained filtrate E is discharged as sewage, and 114 g of filter residue B is crude selenium.

[0036] The composition tables of each recovered product are shown in Table 4.

[0037] Table 4 Composition Table of Recovered Products Example 3 A method for comprehensively recovering tellurium, copper, gold, silver, and selenium from tellurium-copper slag, comprising the following steps: ⑴ In a wet ball mill, 1 kg of tellurium-copper slag with a particle size not greater than 20 mm (as shown in Table 5) is ball-milled with water at a liquid-solid ratio (L / kg) of 2:3, obtaining a ball-milled slurry with a solid particle size of less than 200 µm.

[0038] Table 5 Composition Table of Tellurium-Copper Slag ⑵ Add liquid caustic soda with a mass concentration of 50% to the ball-milled slurry, such that the mass ratio (kg / kg) of sodium hydroxide in the liquid caustic soda to the tellurium-copper slag is 2:3, and maintain the mass ratio (kg / kg) of water to the tellurium-copper slag at 10:1 by adding water. During this process, saturated steam with a temperature above 100 °C and compressed air with a pressure of 0.6 MPa are introduced to ensure that the temperature in the reaction system remains above 90 °C. After stirring and reacting for 0.5 hours, filter to obtain 10.3 L of leachate and 548 g of leach residue.

[0039] ⑶ Slurry the leach residue with water at a liquid-solid ratio (L / kg) of 15:1, then add concentrated sulfuric acid to make the volume concentration of sulfuric acid in the reaction tank 50%. After mixing and stirring at a temperature above 70 °C for 0.5 hours, filter to obtain 4.98 g of gold-silver residue and 8.5 L of filtrate A respectively; the gold-silver residue is returned to the copper smelting precious metal recovery system to recover gold and silver.

[0040] ⑷ Heat filtrate A in a concentration reaction kettle to above 90 °C for evaporation and concentration. After the liquid volume is reduced by half, cool for crystallization. When the temperature drops to 50 °C, discharge the crystallized substances and the solution in the concentration kettle together, and filter with a filter press to obtain 312 g of copper sulfate. Filtrate B is returned to step ⑶. The copper sulfate is sold externally or further refined to recover copper.

[0041] ⑸ Heat the leachate to above 90 °C, and slowly add a saturated sodium hydrosulfide solution. The molar ratio of tellurium in the leachate to the saturated sodium hydrosulfide solution is 1:1. After reacting and transforming for more than 30 minutes, filter to obtain 10.2 L of filtrate C and filter residue A respectively; filter residue A is returned to step ⑴.

[0042] ⑹ Add concentrated sulfuric acid to filtrate C to neutralize the pH to 6, stir for more than 30 minutes until the pH value is stable and the tellurium content in the solution is lower than 200 mg / L, then filter to obtain 248 g of tellurium powder and 10.7 L of filtrate D.

[0043] ⑺ Heat filtrate D to above 70 °C, then add a saturated sodium sulfite solution according to 1 - 3 times the molar content of tellurium in filtrate D, and adjust the pH value of the solution to 2 with dilute sulfuric acid or liquid caustic soda. After reacting for 4 hours, filter. The obtained filtrate E is discharged as sewage, and 172 g of filter residue B is crude selenium.

[0044] The component table of each recycled product is shown in Table 6.

[0045] Table 6 Component Table of Recycled Products

Claims

1. A method for comprehensively recovering tellurium, copper, gold, silver and selenium from tellurium copper slag, comprising the following steps: ⑴ In a wet ball mill, copper telluride slag and water are ball-milled at a liquid-solid ratio (L / kg) of 1:1~2:3 to obtain ball-milled slurry; (2) adding liquid caustic soda with a mass concentration of 30% to 50% to the ball mill slurry, so that the mass ratio of sodium hydroxide to copper telluride slag in the liquid caustic soda is 1:1 to 2:3, and maintaining the mass ratio of water to copper telluride slag at 3:1 to 10:1 by adding water, during which saturated steam with a temperature of more than 100° C. and compressed air with a pressure of 0.1 to 0.6 MPa are blown in to ensure that the temperature in the reaction system is maintained above 85° C., stirring the reaction for 0.5 to 3 hours, and then filtering to obtain a leachate and a leachate slag; ⑶ Add water to the leached residue at a liquid-to-solid ratio of 10:1 to 20:1 (L / kg) to make it slurry, then add concentrated sulfuric acid to make the volume concentration of sulfuric acid in the reaction tank 30% to 50%, mix and stir to react, and then filter to obtain gold and silver residues and filtrate A respectively; the gold and silver residues are returned to the copper smelting precious metal recovery system to recover gold and silver; (4) The filtrate A is evaporated and concentrated, and after the liquid volume is reduced by half, the temperature is lowered and crystallized, and the temperature is lowered to 40-50° C. and then filtered to obtain copper sulfate, and the filtrate B is returned to step (3); (5) The leachate is heated to above 90° C., and a saturated sodium hydrosulfide solution is slowly added, wherein the molar ratio of tellurium to the saturated sodium hydrosulfide solution in the leachate is 1:1, and the mixture is reacted for more than 30 to 60 minutes and then filtered to obtain a filtrate C and a filter residue A, respectively; the filter residue A is returned to step (1); (6) After adding concentrated sulfuric acid to the filtrate C to neutralize the pH to 5-6, stirring for more than 30-60 minutes until the pH value is stable and the tellurium content in the solution is less than 200 mg / L, filtering is performed to obtain tellurium powder and filtrate D; ⑺After the filtrate D is heated to above 70°C, a saturated sodium sulfite solution is added according to 1 to 3 times the molar content of tellurium in the filtrate D, and the pH value of the solution is adjusted to 2 to 3 with dilute sulfuric acid or liquid alkali. After reacting for 4 to 8 hours, filter the obtained filtrate E and discharge it as sewage. The filter residue B is crude selenium.

2. The method for comprehensive recovery of tellurium, copper, gold, silver and selenium from tellurium copper slag according to claim 1, characterized in that: The tellurium copper slag in step (1) is telluride copper slag with a tellurium content greater than 3%.

3. The method for comprehensive recovery of tellurium, copper, gold, silver and selenium from tellurium copper slag as claimed in claim 1, characterized in that: The particle size of the solid particles in the ball-milled slurry in step (1) is less than 200 μm.

4. The method for comprehensive recovery of tellurium, copper, gold, silver and selenium from tellurium copper slag as claimed in claim 1, characterized in that: The mixing and stirring reaction conditions in step (3) are that the temperature is above 70° C. and the reaction time is 0.5 to 2 hours.

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