Comprehensive recovery method for copper, tellurium and silver in tellurium-containing copper slag

Abstract

The invention relates to a comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag, which comprises the following steps: (1) ammoniacal leaching: adding tellurium-containing copper slag into an ammonia water solution, stirring for reaction, and carrying out solid-liquid separation to obtain an ammonia leaching solution and ammonia leaching slag; (2) copper and tellurium separation: adjusting the pH value of the ammonia leaching solution, then carrying out solid-liquid separation, and adding a caustic alkali solution into the obtained mixed precipitate for reaction to obtain a sodium tellurite solution and a copper hydroxide precipitate; (3) copper and tellurium vulcanization replacement: adding a sodium sulfide solution into the ammonia leaching residues for reaction, adding a sodium tellurite solution and a sulfuric acid solution into the obtained filtrate for reaction to obtain elemental tellurium with the purity of more than 98%; the obtained slag phase is used for recovering copper and gold and silver; and (4) preparation of magnesium tellurite: adjusting the pH value of the sodium tellurite solution, and then adding magnesium chloride solid for reaction to obtain a magnesium tellurite product with the purity of 98.5-99.5%. The method is short in process, easy to operate and low in cost, magnesium tellurite, elemental tellurium products and copper hydroxide by-products with high added values can be prepared, and precious metals such as gold and silver in the slag phase are remarkably enriched.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag. Background Art

[0002] Tellurium-containing copper slag is a solid slag formed by reducing copper powder with the acid leaching liquid produced by oxidative acid leaching of anode mud produced by copper electrolytic refining. The main components of tellurium-containing copper slag are Cu30-45%, Te35%-50%, Se0.5%-1%, Fe3%-5%, O10%-15%, Ag100-500g / t, Au20-40g / t, and other 1-1.5%. It mainly exists in two physical phases: copper tellurite and copper telluride formed by copper and tellurium. At present, there are two main processes for copper and tellurium recovery: pyrometallurgy and hydrometallurgy.

[0003] The pyrometallurgical process is mainly vacuum distillation, which first mixes telluride copper slag with sulfur to make blocks, then performs sulfidation smelting, and then vacuum distills the obtained sulfide product to obtain cuprous sulfide residue and pure tellurium. This method can achieve comprehensive recovery of copper and tellurium, but it requires high temperature treatment and protective atmosphere to complete, which is costly and difficult to achieve industrial application.

[0004] The wet process mainly uses oxidative acid leaching-copper and tellurium separation-electrolysis or oxidative acid leaching-copper and tellurium separation-reduction tellurium precipitation to recover copper and tellurium, but the process is long and the cost is high.

[0005] Therefore, there is an urgent need to develop a method for efficiently and comprehensively recovering copper and tellurium from tellurium-containing copper slag. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a comprehensive recovery method for copper, tellurium and silver in tellurium-containing copper slag with short process, easy operation and low cost.

[0007] In order to solve the above problems, a comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag according to the present invention comprises the following steps: ⑴Ammonia leaching: At room temperature, the tellurium-containing copper slag is first slurried, and then an ammonia solution with a mass concentration of 30 wt% is added at a flow rate of 0.2-1.5 L / min and a liquid-to-solid ratio of 5-10:1, and the solid-liquid separation is carried out after stirring the reaction. The obtained precipitate is washed to obtain an ammonia leaching solution and an ammonia leaching residue; ⑵Separation of copper and tellurium: A sulfuric acid solution with a mass concentration of 30wt% is added to the ammonia leaching solution to make the solution pH=6-7, and a liquid phase and a mixed precipitate are obtained by solid-liquid separation; the liquid phase is sent to a water treatment workshop for treatment and then discharged in compliance with the standards; after the mixed precipitate is washed, a caustic soda solution with a mass concentration of 50wt% is added to the mixed precipitate according to 1.1 times the theoretical amount of the reaction of tellurium dioxide and sodium hydroxide, and the mixture is stirred for reaction and then filtered to obtain a sodium tellurite solution and a copper hydroxide precipitate; ⑶Copper and tellurium sulfide replacement: At room temperature, sodium sulfide solution is added to the ammonia leached residue at a liquid-solid ratio of 5-10:1, and the reaction is carried out for 40-60 minutes before solid-liquid separation to obtain a filtrate and a slag phase; the sodium tellurite solution is added to the filtrate according to a theoretical amount, and a sulfuric acid solution with a mass concentration of 10wt% is added to make the solution pH=5-6, and the solution is stirred for reaction, filtered, washed, and dried to obtain a single tellurium and sodium sulfate solution with a purity of more than 98%; the sodium sulfate solution is sent to a water treatment workshop for treatment and then discharged after meeting the standards; the slag phase is used to recover copper and gold and silver; ⑷ Preparation of magnesium tellurite: A hydrochloric acid solution with a mass concentration of 30 wt% is added to the sodium tellurite solution to make the pH value of the solution equal to 8-9, and then magnesium chloride solid is added according to the theoretical amount of the reaction between sodium tellurite and magnesium chloride under room temperature conditions, and after stirring for reaction, the mixture is filtered, washed and dried to obtain a magnesium tellurite product with a purity of 98.5%-99.5% and a sodium chloride solution; and the sodium chloride solution is returned to the magnesium tellurite preparation equipment.

[0008] In the step (1), the tellurium-containing copper slag contains 30-45% Cu, 35-50% Te, 0.5-1% Se, 3-5% Fe, 10-15% O, 100-500 g / t Ag, 20-40 g / t Au, and 1-1.5% others.

[0009] The stirring reaction conditions in step (1) refer to a stirring rate of 20-30 r / min and a reaction time of 30-90 min.

[0010] The washing liquid used in step (1) is a 30-40° C., 10 wt %-15 wt % ammonia solution, and the washing times are 3-5 times.

[0011] The washing liquid used in step (2) is 40°C water, and the washing times are 3 to 5 times.

[0012] The stirring reaction conditions in step (2) refer to a stirring rate of 100 r / min and a reaction time of 25 to 35 min.

[0013] In the step (2), the sodium tellurite solution is allowed to stand at 10-15° C. for 24 hours and then filtered again.

[0014] The stirring reaction conditions in step (3) refer to a stirring rate of 50-100 r / min, a reaction temperature of 50-85° C., and a reaction time of 0.5-3 h.

[0015] The stirring reaction conditions in step (4) refer to a stirring rate of 10 to 150 r / min and a reaction time of 1.5 to 2.5 h.

[0016] Compared with the prior art, the present invention has the following advantages: 1. The present invention uses ammonia water as a single leaching agent, can efficiently leach Cu and Te at room temperature, can effectively inhibit impurity elements such as Fe from entering the solution, and the impurity content of the ammonia leaching solution is low.

[0017] 2. The present invention adds sodium sulfide solution to the ammonia leached residue for sulfidation replacement, thereby achieving deep separation of copper and tellurium, so that precious metals such as gold and silver are significantly enriched in the slag phase after replacement.

[0018] 3. The present invention adds the in-process sodium tellurite solution to the liquid phase after sulfidation replacement, and controls the solution pH to 6-7, thereby generating elemental tellurium and realizing comprehensive recovery of tellurium.

[0019] 4. The process of the present invention is short, easy to operate and low in cost.

[0020] 5. By adopting the method of the present invention, high value-added magnesium tellurite and elemental tellurium products and copper hydroxide by-products can be prepared from tellurium-containing copper slag, so that precious metals such as gold and silver in the slag phase can be significantly enriched. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0022] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0023] like Figure 1 As shown, a comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag comprises the following steps: ⑴ Ammonia leaching: Tellurium-containing copper slag is leached with ammonia to separate copper, tellurium and impurities.

[0024] At room temperature, the tellurium-containing copper slag is first slurried, and then an ammonia solution with a mass concentration of 30wt% is added at a flow rate of 0.2~1.5L / min and a liquid-to-solid ratio (L / kg) of 5~10:1. After reacting for 30~90min under a stirring rate of 20~30r / min, the solid-liquid separation is carried out, and the obtained precipitate is washed to obtain an ammonia leaching solution and an ammonia leaching residue.

[0025] Among them: tellurium-containing copper slag contains Cu30~45%, Te35%~50%, Se0.5%~1%, Fe3%~5%, O10%~15%, Ag100~500g / t, Au20~40g / t, and others 1~1.5%.

[0026] The washing liquid used for washing is a 30-40° C., 10 wt %-15 wt % ammonia solution, and the washing times are 3-5 times.

[0027] ⑵ Separation of copper and tellurium: The ammonia leaching solution is neutralized to promote the co-precipitation of copper ions and tellurite, and the separation of copper and tellurium is achieved through alkaline leaching.

[0028] A sulfuric acid solution with a mass concentration of 30wt% is added to the ammonia leaching solution to make the solution pH = 6~7, so as to promote the copper ions and tellurite ions to generate a mixed precipitation of copper hydroxide and tellurium dioxide, and the liquid phase and the mixed precipitation are obtained through solid-liquid separation.

[0029] The liquid phase is sent to the water treatment workshop for treatment and meets the discharge standards; after the mixed precipitate is washed, a caustic soda solution with a mass concentration of 50wt% is added to the mixed precipitate at 1.1 times the theoretical amount of tellurium dioxide and sodium hydroxide reaction, the stirring rate is 100r / min, and the reaction is carried out for 25~35min and then filtered to obtain sodium tellurite solution and copper hydroxide precipitate.

[0030] Among them: the washing liquid used for washing is 40℃ water, and the washing times are 3 to 5 times.

[0031] The sodium tellurite solution was allowed to stand at 10-15°C for 24 hours and then filtered again.

[0032] ⑶ Sulfidation replacement of copper and tellurium: The ammonia leached slag is subjected to sulfidation replacement to separate copper and tellurium.

[0033] At room temperature, sodium sulfide solution is added to the ammonia leached residue at a liquid-to-solid ratio (mL / g) of 5-10:1 (that is, sodium sulfide is added at a mass ratio of tellurium element to sulfur element in the ammonia leached residue of 1:1), and the solid-liquid separation is carried out after reaction for 40-60 minutes to obtain a filtrate and a slag phase; sodium tellurite solution is added to the filtrate according to a theoretical amount, and a sulfuric acid solution with a mass concentration of 10wt% is added to make the solution pH=5-6, and the reaction is carried out for 0.5-3h under the conditions of a stirring rate of 50-100r / min and a reaction temperature of 50-85°C, and then filtered, washed and dried to obtain a single tellurium and sodium sulfate solution with a purity of more than 98%.

[0034] The sodium sulfate solution is sent to the water treatment workshop for treatment and then discharged after meeting the standards; the gold and silver content in the slag phase can be increased by more than 5 times, with a significant enrichment effect. The slag phase is used to recover a small amount of copper and precious metals such as gold and silver.

[0035] ⑷ Preparation of magnesium tellurite: Add magnesium chloride crystals to sodium tellurite solution to prepare magnesium tellurite.

[0036] A hydrochloric acid solution with a mass concentration of 30wt% is added to the sodium tellurite solution to make the pH value of the solution equal to 8-9, and then magnesium chloride solid is added according to the theoretical amount of the reaction between sodium tellurite and magnesium chloride under room temperature conditions, and the reaction is carried out for 1.5-2.5h under a stirring rate of 10-150r / min, and then filtered, washed and dried to obtain a magnesium tellurite product with a purity of 98.5%-99.5% and a sodium chloride solution; the sodium chloride solution is returned to the magnesium tellurite preparation equipment.

[0037] The reagents used in the present invention, such as sulfuric acid, ammonia water, hydrochloric acid and sodium hydroxide, are all of industrial grade.

[0038] Working principle of the present invention: Ammonia solution is added to the ground copper-telluride slag to make the copper tellurite in the slag react with ammonia solution to dissolve. The resulting ammonia leaching solution is neutralized by adding sulfuric acid to promote the co-precipitation of copper and tellurium, and caustic soda solution is added to the precipitate to separate copper and tellurium, so as to obtain copper hydroxide precipitate and sodium tellurite solution. The main component of the ammonia leaching slag is copper telluride. Since the solubility product of copper telluride is much larger than that of copper sulfide, the deep separation of copper and tellurium is achieved by adding sodium sulfide solution for sulfidation replacement. Sodium tellurite solution is added to the filtrate obtained by sulfidation replacement of the ammonia leaching slag, and sulfuric acid is added to control the pH of the solution to 5~6, so that a neutralization reaction can occur to generate elemental tellurium.

[0039] Reaction equation of the present invention is: CuTeO 3 +4NH 3 +2H 2 O=(NH 4 ) 2 TeO 3 +Cu(NH 3 ) 2 (OH) 2 (NH 4 ) 2 TeO 3 +H 2 SO 4 =(NH 4 ) 2 SO 4 +TeO 2 ↓+H 2 O Cu(NH 3 ) 2 (OH) 2 +H 2 SO 4 =Cu(OH) 2 ↓+(NH 4 ) 2 SO4 TeO 2 +2NaOH=Na 2 TeO 3 +H 2 O 2Na 2 Te+Na 2 TeO 3 +3H 2 SO 4 =3Na 2 SO 4 +3Te↓+3H 2 O CuTe+Na 2 S=CuS+Na 2 Te Na 2 TeO 3 +MgCl 2 =MgTeO 3 ↓+2NaCl Example 1 A comprehensive recovery method for copper, tellurium and silver in tellurium-containing copper slag comprises the following steps: ⑴Ammonia leaching: Tellurium-containing copper slag (Cu30%, Te50%, Se1%, Fe5%, O13%, Ag100g / t, Au20g / t, other 0.99%) was ground to a particle size of -80 mesh, and 1kg was weighed. After slurrying, it was pumped into an ammonia leaching equipment, and then 3.7L of 30wt% ammonia solution was added at a flow rate of 0.2L / min and a liquid-to-solid ratio (L / kg) of 5:1 at room temperature. After reacting for 90min at a stirring rate of 20r / min, the solid-liquid separation was carried out to obtain 3.67L of ammonia leaching solution and 140g of ammonia leaching residue.

[0040] ⑵Separation of copper and tellurium: About 2.81L 30wt% sulfuric acid solution was added to the ammonia leaching solution to make the solution pH = 6~7, so as to promote the copper ions and tellurite ions to generate copper hydroxide and tellurium dioxide mixed precipitation, solid-liquid separation, and the obtained liquid phase was sent to the water treatment workshop for treatment and then discharged in compliance with the standards; 383mL 50wt% caustic soda solution was added to the obtained 921g mixed precipitation according to 1.1 times the theoretical amount of tellurium dioxide and sodium hydroxide reaction, the stirring rate was 100r / min, and the reaction was filtered after 25min. 365mL c((Na 2 TeO 3 ) = 1.92 g / mL sodium tellurite solution and 390 g copper hydroxide precipitate.

[0041] ⑶Copper and tellurium sulfide replacement: 140g of ammonia leached slag was slurried and pumped to the copper and sulfur replacement equipment. At room temperature, 700mL of sodium sulfide solution was added at a liquid-to-solid ratio of 5:1 (sodium sulfide was added at a mass ratio of 1:1 between tellurium and sulfur in the ammonia leached slag, i.e. 54.8g). After 60min of reaction, the solid and liquid were separated. 2 Te) = 0.17g / mL solution, add 28mL of the obtained sodium tellurite solution according to the theoretical amount, and add 10wt% sulfuric acid solution to make the solution pH = 5~6, react for 0.5h under the conditions of stirring rate of 100r / min and reaction temperature of 85℃, filter, wash and dry, and 89g of elemental tellurium with purity > 98% can be obtained; the obtained sodium sulfate solution is used for treatment in the water treatment workshop and discharged when it meets the standards. The gold and silver content in the obtained slag phase can be increased by more than 5 times, and the enrichment effect is significant. The slag phase is used to recover a small amount of copper and precious metals such as gold and silver.

[0042] ⑷ Preparation of magnesium tellurite: 30 wt% hydrochloric acid solution was added to the obtained 326 mL sodium tellurite solution to adjust the pH value of the solution to 8-9. Then, sodium tellurite and magnesium chloride were reacted at room temperature, and 263 g of magnesium chloride solid was added in a theoretical amount. The mixture was reacted for 1.5 h at a stirring rate of 100 r / min. After filtering, washing and drying, 759 g of magnesium tellurite product with a purity of 98.5% was obtained.

[0043] Example 2 A comprehensive recovery method for copper, tellurium and silver in tellurium-containing copper slag comprises the following steps: ⑴Ammonia leaching: Tellurium-containing copper slag (Cu45%, Te35%, Se0.5%, Fe4%, O13.95%, Ag500g / t, 40g / t, other 1.5%) was ground to a particle size of -100 mesh, and 1kg was weighed. After slurrying, it was pumped into the ammonia leaching equipment, and then 7.8L of 30wt% ammonia solution was added at a flow rate of 1.5L / min and a liquid-to-solid ratio (L / kg) of 10:1 at room temperature. After reacting for 30min at a stirring rate of 24r / min, the solid-liquid separation was carried out to obtain 7.78L of ammonia leaching solution and 139.5g of ammonia leaching residue.

[0044] ⑵Separation of copper and tellurium: About 5.5L of 30wt% sulfuric acid solution was added to 7.78L of ammonia leaching solution to make the solution pH = 6~7, so that copper ions and tellurite ions were generated into a mixed precipitate of copper hydroxide and tellurium dioxide, and the solid-liquid separation was performed. The obtained liquid phase was sent to a water treatment workshop for treatment and then discharged in compliance with the standards; 271mL of 50wt% caustic soda solution was added to the obtained 919g mixed precipitate at 1.1 times the theoretical amount of tellurium dioxide and sodium hydroxide, the stirring rate was 100r / min, and the reaction was carried out for 28min before filtering to obtain 330mL of c((Na 2 TeO3 ) = 1.19 g / mL sodium tellurite solution and 585 g copper hydroxide precipitate.

[0045] ⑶Copper and tellurium sulfide replacement: 139.5g of ammonia leached slag was slurried and pumped to the copper and sulfur replacement equipment. At room temperature, 1.40L of sodium sulfide solution was added at a liquid-to-solid ratio of 10:1 (sodium sulfide was added according to the mass ratio of tellurium element to sulfur element in the ammonia leached slag of 1:1, i.e. 82.3g). After reacting for 40 minutes, the solid and liquid were separated. 2 Te) = 0.094g / mL solution, add 68.8mL of the obtained sodium tellurite solution according to the theoretical amount, and add 10wt% sulfuric acid solution to make the solution pH = 5~6, react for 3h at a stirring rate of 100r / min and a reaction temperature of 50℃, filter, wash and dry, and 134g of elemental tellurium with a purity of >98% can be obtained; the obtained sodium sulfate solution is used for treatment in the water treatment workshop and discharged when it meets the standards. The gold and silver content in the obtained slag phase can be increased by more than 5 times, and the enrichment effect is significant. The slag phase is used to recover a small amount of copper and precious metals such as gold and silver.

[0046] ⑷ Preparation of magnesium tellurite: 30 wt % hydrochloric acid solution was added to the obtained 261.2 mL sodium tellurite solution to adjust the solution pH to 8-9. Then, sodium tellurite and magnesium chloride were reacted at room temperature, and 126 g of magnesium chloride solid was added in a theoretical amount. The mixture was reacted for 2.5 h at a stirring rate of 100 r / min. After filtration, washing and drying, 364 g of magnesium tellurite product with a purity of 99.5% was obtained.

[0047] Example 3 A comprehensive recovery method for copper, tellurium and silver in tellurium-containing copper slag comprises the following steps: ⑴Ammonia leaching: Tellurium-containing copper slag (Cu35%, Te45%, Se0.8%, Fe3%, O15%, Ag400g / t, 30g / t, others 1.14%) was ground to a particle size of -150 mesh, 1kg was weighed, slurried and pumped into an ammonia leaching equipment, and then 4.5L of a 30wt% ammonia solution was added at a flow rate of 1.0L / min and a liquid-to-solid ratio (L / kg) of 6:1 at room temperature. After reacting for 50min at a stirring rate of 28r / min, the solid-liquid separation was carried out to obtain 4.47L of ammonia leaching solution and 138g of ammonia leaching residue.

[0048] ⑵Separation of copper and tellurium: About 3.12L of 30wt% sulfuric acid solution was added to 4.47L of ammonia leaching solution to make the solution pH = 6~7, so that copper ions and tellurite ions were generated into a mixed precipitate of copper hydroxide and tellurium dioxide, and the solid-liquid separation was performed. The obtained liquid phase was sent to a water treatment workshop for treatment and then discharged in compliance with the standards; 335mL of 50wt% caustic soda solution was added to the obtained 945g mixed precipitate at 1.1 times the theoretical amount of tellurium dioxide and sodium hydroxide, the stirring rate was 100r / min, and the reaction was carried out for 32min before filtering to obtain 330mL of c((Na 2 TeO 3 ) = 1.55 g / mL sodium tellurite solution and 461 g copper hydroxide precipitate.

[0049] ⑶Copper and tellurium sulfide replacement: 138g of ammonia leached slag was slurried and pumped to the copper and sulfur replacement equipment. At room temperature, 0.97L of sodium sulfide solution was added at a liquid-to-solid ratio of 7:1 (sodium sulfide was added at a mass ratio of 1:1 between tellurium and sulfur in the ammonia leached slag, i.e. 64g). After 45min of reaction, the solid and liquid were separated. 2 Te) = 0.106g / mL solution, add 39mL of the obtained sodium tellurite solution according to the theoretical amount, and add 10wt% sulfuric acid solution to make the solution pH = 5~6, react for 2.5h at a stirring rate of 70r / min and a reaction temperature of 60℃, filter, wash and dry, and obtain 103g of elemental tellurium with a purity of >98%; the obtained sodium sulfate solution is used for treatment in the water treatment workshop and discharged when it meets the standards. The gold and silver content in the obtained slag phase can be increased by more than 5 times, and the enrichment effect is significant. The slag phase is used to recover a small amount of copper and precious metals such as gold and silver.

[0050] ⑷ Preparation of magnesium tellurite: 30 wt % hydrochloric acid solution was added to the obtained 291 mL sodium tellurite solution to adjust the pH value of the solution to 8-9. Then, sodium tellurite and magnesium chloride were reacted at room temperature. 183 g of magnesium chloride solid was added in a theoretical amount. The mixture was reacted for 2 h at a stirring rate of 120 r / min. After filtering, washing and drying, 525 g of magnesium tellurite product with a purity of 98.9% was obtained.

[0051] Example 4 A comprehensive recovery method for copper, tellurium and silver in tellurium-containing copper slag comprises the following steps: ⑴Ammonia leaching: Tellurium-containing copper slag (Cu42%, Te40%, Se0.82%, Fe4.15%, O12%, Ag300g / t, Au25g / t, other 1%) was ground to a particle size of -200 mesh, and 1 kg was weighed. After slurrying, it was pumped into the ammonia leaching equipment, and then 5.3 L of 30wt% ammonia solution was added at a flow rate of 1.2 L / min and a liquid-to-solid ratio (L / kg) of 7:1 at room temperature. After reacting for 70 minutes at a stirring rate of 30 r / min, the solid and liquid were separated to obtain 5.27 L of ammonia leaching solution and 143 g of ammonia leaching residue.

[0052] ⑵Separation of copper and tellurium: About 3.71L 30wt% sulfuric acid solution was added to 5.27L ammonia leaching solution to make the solution pH = 6~7, so that copper ions and tellurite ions were promoted to generate copper hydroxide and tellurium dioxide mixed precipitation, solid-liquid separation, and the obtained liquid phase was sent to the water treatment workshop for treatment and then discharged in compliance with the standards; 287mL 50wt% caustic soda solution was added to the obtained 886g mixed precipitation according to 1.1 times the theoretical amount of tellurium dioxide and sodium hydroxide reaction, the stirring rate was 100r / min, and the reaction was filtered after 35min. 350mL c((Na 2 TeO 3 ) = 1.25 g / mL sodium tellurite solution and 486 g copper hydroxide precipitate.

[0053] ⑶Copper and tellurium sulfide replacement: 143g of ammonia leached slag was slurried and pumped to the copper and sulfur replacement equipment. At room temperature, 1.14L of sodium sulfide solution was added at a liquid-to-solid ratio of 8:1 (sodium sulfide was added at a mass ratio of 1:1 between tellurium and sulfur in the ammonia leached slag, i.e. 82g). After 45min of reaction, the solid and liquid were separated. The obtained 1.11L c(Na 2 Te) = 0.114g / mL solution, add 62mL of sodium tellurite solution obtained in (2) according to the theoretical amount, and add 10wt% sulfuric acid solution to make the solution pH = 5~6, react for 2h at a stirring rate of 90r / min and a reaction temperature of 75℃, filter, wash and dry, and 132g of elemental tellurium with a purity of >98% can be obtained; the obtained sodium sulfate solution is sent to the water treatment workshop for treatment and discharged when it meets the standards. The gold and silver content in the obtained slag phase can be increased by more than 5 times, and the enrichment effect is significant. The slag phase is used to recover a small amount of copper and precious metals such as gold and silver.

[0054] ⑷ Preparation of magnesium tellurite: 30 wt % hydrochloric acid solution was added to the obtained 291 mL sodium tellurite solution to adjust the solution pH to 8-9. Then, sodium tellurite and magnesium chloride were reacted at room temperature. 146 g of magnesium chloride solid was added in a theoretical amount. The mixture was reacted for 1.8 h at a stirring rate of 140 r / min. After filtration, washing and drying, 420 g of magnesium tellurite product with a purity of 98.9% was obtained.

Claims

1. A comprehensive recovery method for copper, tellurium and silver in tellurium-containing copper slag, comprising the following steps: ⑴Ammonia leaching: At room temperature, the tellurium-containing copper slag is first slurried, and then an ammonia solution with a mass concentration of 30 wt% is added at a flow rate of 0.2-1.5 L / min and a liquid-to-solid ratio of 5-10:1, and the solid-liquid separation is carried out after stirring the reaction. The obtained precipitate is washed to obtain an ammonia leaching solution and an ammonia leaching residue; ⑵Separation of copper and tellurium: A sulfuric acid solution with a mass concentration of 30 wt% is added to the ammonia leaching solution to make the solution pH = 6-7, and a liquid phase and a mixed precipitate are obtained by solid-liquid separation; the liquid phase is sent to a water treatment workshop for treatment and then discharged in compliance with the standards; After the mixed precipitate is washed, a caustic soda solution with a mass concentration of 50 wt% is added to the mixed precipitate according to 1.1 times the theoretical amount of tellurium dioxide and sodium hydroxide reaction, and the mixture is stirred for reaction and then filtered to obtain a sodium tellurite solution and a copper hydroxide precipitate; ⑶Copper and tellurium sulfide replacement: At room temperature, sodium sulfide solution is added to the ammonia leached residue at a liquid-solid ratio of 5-10:1, and the reaction is carried out for 40-60 minutes before solid-liquid separation to obtain a filtrate and a slag phase; the sodium tellurite solution is added to the filtrate according to a theoretical amount, and a sulfuric acid solution with a mass concentration of 10wt% is added to make the solution pH=5-6, and the solution is stirred for reaction, filtered, washed, and dried to obtain a single tellurium and sodium sulfate solution with a purity of more than 98%; the sodium sulfate solution is sent to a water treatment workshop for treatment and then discharged after meeting the standards; the slag phase is used to recover copper and gold and silver; ⑷ Preparation of magnesium tellurite: A hydrochloric acid solution with a mass concentration of 30 wt% is added to the sodium tellurite solution to make the pH value of the solution equal to 8-9, and then magnesium chloride solid is added according to the theoretical amount of the reaction between sodium tellurite and magnesium chloride under room temperature conditions, and after stirring for reaction, the mixture is filtered, washed and dried to obtain a magnesium tellurite product with a purity of 98.5%-99.5% and a sodium chloride solution; and the sodium chloride solution is returned to the magnesium tellurite preparation equipment.

2. The comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag according to claim 1, characterized in that: In the step (1), the tellurium-containing copper slag contains 30-45% Cu, 35-50% Te, 0.5-1% Se, 3-5% Fe, 10-15% O, 100-500 g / t Ag, 20-40 g / t Au, and 1-1.5% others.

3. The comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag according to claim 1, characterized in that: The stirring reaction conditions in step (1) refer to a stirring rate of 20-30 r / min and a reaction time of 30-90 min.

4. The comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag according to claim 1, characterized in that: The washing liquid used in step (1) is a 30-40° C., 10 wt %-15 wt % ammonia solution, and the washing times are 3-5 times.

5. The comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag according to claim 1, characterized in that: The washing liquid used in step (2) is 40°C water, and the washing times are 3 to 5 times.

6. The comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag according to claim 1, characterized in that: The stirring reaction conditions in step (2) refer to a stirring rate of 100 r / min and a reaction time of 25 to 35 min.

7. The comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag according to claim 1, characterized in that: In the step (2), the sodium tellurite solution is allowed to stand at 10-15° C. for 24 hours and then filtered again.

8. The comprehensive recovery method of copper, tellurium and silver from tellurium-containing copper slag according to claim 1, characterized in that: The stirring reaction conditions in step (3) refer to a stirring rate of 50-100 r / min, a reaction temperature of 50-85° C., and a reaction time of 0.5-3 h.

9. The comprehensive recovery method of copper, tellurium and silver in tellurium-containing copper slag according to claim 1, characterized in that: The stirring reaction conditions in step (4) refer to a stirring rate of 10 to 150 r / min and a reaction time of 1.5 to 2.5 h.

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