Method for extracting high-purity rhenium from copper smelting waste acid

Abstract

The invention discloses a method for extracting high-purity rhenium from copper smelting waste acid, which is characterized by comprising the following steps: (1) filtering to remove solid particles in the waste acid; (2) carrying out ion exchange on the filtered waste acid to obtain crude ammonium rhenate; (3) pouring the crude ammonium rhenate into a recrystallization kettle for recrystallization to form an ammonium rhenate crude product; and (4) adding hydrogen peroxide into the ammonium rhenate crude product, and recrystallizing to obtain ammonium rhenate crystals. Through a large number of experimental studies, it is found that high-purity ammonium rhenate can be obtained by adding a small amount of hydrogen peroxide and N, N-dimethylformamide in the recrystallization process, and meanwhile the recovery rate of rhenium is also remarkably increased.

Description

Technical Field

[0001] The present invention relates to the field of metallurgical technology, and particularly relates to a method for extracting high-purity rhenium from waste acid in copper smelting. Background Art

[0002] Rhenium is a very scarce and continuously appreciating rare metal, and its content in the earth's crust is only greater than protactinium and radium elements. Currently, it is widely used in modern industry, mainly as catalysts in the petroleum industry and the automotive industry, petroleum reforming catalysts, rhenium alloys in the electronics industry and the aerospace industry, etc. Rhenium plays an irreplaceable role in modern industry by other metals. Most of the rhenium in copper raw materials exists in the forms of CuReS 4 and ReS 2 During the copper matte smelting process, it is completely oxidized to Re 2 O 7 When the concentration of SO 2 is relatively high, a part of Re 2 O 7 is reduced to ReO 3 and ReO 2 Under the smelting atmosphere, almost all of the rhenium oxides enter the flue gas. After cooling, a small amount enters the dust, and about 85% of the rhenium reacts with water during the flue gas purification and washing to form perrhenic acid and enters the waste acid. Currently, the content of valuable metal rhenium in the waste acid and waste liquid of copper smelting enterprises is generally above 1 mg / L of Re. Some copper smelting enterprises return the sulfide slag obtained after treating the waste acid to the smelting process to increase the concentration of valuable metal rhenium in the waste acid, and then the rhenium content in the waste acid and waste liquid can reach above 40 mg / L.

[0003] Chinese Patent Application CN107460320A discloses a new process for recovering metal rhenium from waste acid in copper smelting. Through processes such as pretreatment, centrifugal extraction, centrifugal washing, centrifugal back-extraction, concentration, freeze crystallization, and recrystallization, valuable metal rhenium in the waste acid of copper smelting is recovered, and then a high-purity ammonium perrhenate product is obtained. At the same time, the entire process flow design can achieve PLC online automatic control. However, this method can only obtain an ammonium perrhenate product with a purity of 99.95% through the recrystallization process.

[0004] Chinese patent CN105384195B discloses a method for recovering rhenium from molybdenum smelting waste acid, which comprises: 1) filtering the molybdenum smelting waste acid, and adsorbing the filtrate through a composite amino-ethylene weak base anion exchange resin column until adsorption is saturated; 2) desorbing with ammonia water after adsorption is saturated, collecting the desorbed liquid, and evaporating and crystallizing to obtain ammonium perrhenate. Among them, the composite amino-ethylene weak base anion exchange resin has a large saturated adsorption capacity for rhenium, and the rhenium content in the desorbed liquid is more than 100 times richer than the rhenium in the waste acid, and the recovery rate of rhenium is higher than that of the existing extraction method and ion exchange method, reaching more than 98%. At the same time, the solubility difference of ammonium perrhenate, ammonium molybdate, and ammonium sulfate is utilized, and the ammonium perrhenate is purified by evaporation and crystallization operation, and the purity of the obtained ammonium perrhenate reaches more than 99.9%. However, this method requires the addition of at least 1% hydrogen peroxide and at least 1% ammonia water during the evaporation and crystallization process, which inevitably increases the operating cost.

[0005] In addition, China's authorized patent CN105969985B discloses a method for comprehensive recovery of rhenium and copper from copper smelting waste acid, which is to filter and remove lead from copper smelting waste acid, then target rhenium precipitation to obtain rhenium-rich slag, and then hot-press oxidative leaching to obtain rhenium-rich leachate, and the concentration of rhenium after evaporation and concentration is 10g / L-20g / L, and potassium perrhenate is obtained by rhenium precipitation and recrystallization with KCl, and the liquid after rhenium precipitation is subjected to sulfide precipitation of copper. However, in this patent, the object of recrystallization is potassium perrhenate, and KCl needs to be added additionally to precipitate rhenium, which increases the cost.

[0006] Chinese invention patent CN 119038611 A discloses a method for purifying ammonium rhenate, which includes a primary dissolution crystallization, a secondary dissolution crystallization, resin preheating, ion exchange, resin rhenium washing, resin regeneration, resin acid washing, and ammonium rhenate neutralization and filtration process, wherein in the secondary dissolution crystallization step, hydrogen peroxide with a mass of 1.2 to 1.8% of the ammonium rhenate crystal is added for oxidation. By controlling the amount of hydrogen peroxide added, not only the chromaticity of the obtained ammonium rhenate is better, but also the purity of the ammonium rhenate after purification can reach more than 99.995%, and the purification effect is good. However, in this patent application, a large amount of hydrogen peroxide needs to be added for oxidation, and it also needs to be further purified by ion exchange resin, resulting in excessively high production costs.

[0007] Therefore, how to further improve the purity and recovery rate of the recovered rhenium while reducing the recovery cost is still a technical problem that needs to be solved urgently by technicians in this field. Summary of the invention

[0008] In view of this, the present invention provides a method for extracting high-purity rhenium from copper smelting waste acid. To achieve the above object, the present invention mainly provides the following technical solutions:

[0009] One aspect of the present invention relates to a method for extracting high-purity rhenium from waste acid in copper smelting, which comprises the following steps:

[0010] (1) Take the waste acid from copper smelting, and use an acid-resistant pump to pump the waste acid into a filter to remove solid particles in the waste acid;

[0011] (2) The filtered waste acid is pumped into a cation exchange resin column by an upper liquid pump for adsorption. After adsorption saturation, the ion exchange column is washed with demineralized water, and then ammonia water is used for desorption. After desorption, it is pumped into a desorption liquid tank, and then drawn into an evaporation pan for vacuum evaporation. After evaporation, a refrigerator is used to cool the temperature to 1-4 °C, and then it is placed on a suction filter plate for suction filtration. After suction filtration, crude ammonium perrhenate is obtained;

[0012] (3) Pour the crude ammonium perrhenate into a recrystallization pan. For every 10 kg of crude ammonium perrhenate, add 25-35 kg of demineralized water. Use steam to heat it to 75-85 °C again and keep it for 20-40 minutes. After filtering through a filter, it is connected to a bucket and cooled naturally. Then, a refrigerator is used to cool the temperature to 2-3 °C. After freezing, it is put into a filter again for filtration. After removing moisture, crude ammonium perrhenate is formed;

[0013] (4) Put demineralized water into a dissolution kettle and heat it to 75-85 °C. For every 40 kg of demineralized water, add 8-12 kg of crude ammonium perrhenate. At the same time, add hydrogen peroxide accounting for 0.1-0.3 wt% of the demineralized water amount and do not add any other components. Keep it at 70-80 °C in the dissolution kettle and stir until all crystals are dissolved. Filter the solution to obtain a filtrate. Add N,N-dimethylformamide accounting for 0.08-0.3 wt% of the total filtrate amount. After the filtrate is cooled to room temperature, put the feed liquid bucket into a freezer for freezing to make the solution temperature drop to 1-3 °C, and filter to obtain ammonium perrhenate crystals.

[0014] In a preferred embodiment of the present invention, in step (4), hydrogen peroxide accounting for 0.12-0.18 wt% of the demineralized water amount is added.

[0015] In a preferred embodiment of the present invention, in step (4), 0.18-0.22 wt% of N,N-dimethylformamide is added to the filtrate obtained by filtering the solution, and then crystallization is carried out to obtain crystals. In this preferred embodiment, the purity and recovery rate of ammonium perrhenate crystals can be further improved.

[0016] In a preferred embodiment of the present invention, in step (1), the acid solution contains 3-4 g / L of Cu, 60-70 mg / L of Re, and 20-30 g / L of sulfuric acid.

[0017] In a preferred embodiment of the present invention, the purity of the ammonium perrhenate crystals is above 99.99%; preferably above 99.995%.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] Through a large number of experimental studies, the present invention finds that by adding a small amount of hydrogen peroxide and N,N-dimethylformamide during the recrystallization process, ammonium perrhenate with high purity can be obtained, and at the same time, the recovery rate of rhenium is also significantly improved. Detailed implementation manners

[0020] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following takes a preferred embodiment to illustrate in detail the specific implementation manners, technical solutions, features and their effects of the application according to the present invention.

[0021] Example 1

[0022] (1) Take copper smelting waste acid, conduct component analysis, and measure that the acid solution contains 3.5 g / L of Cu, 65 mg / L of Re, and 25.3 g / L of sulfuric acid. Use an acid-resistant pump to pump the waste acid into a filter to remove solid particles in the waste acid.

[0023] (2) The filtered waste acid is pumped into a cation exchange resin column by an upper liquid pump for adsorption. After adsorption saturation, the ion exchange column is washed with demineralized water, and then ammonia water is used for desorption. After desorption, it is pumped into a desorption liquid tank and then drawn into an evaporation pan to evaporate with steam at 0.2 MPa. After evaporation, a refrigerator is used to cool the temperature to 2 - 3 °C, and then it is placed on a suction filter plate for suction filtration. After suction filtration, crude ammonium perrhenate is obtained.

[0024] (3) Pour the crude ammonium perrhenate into a recrystallization pan. For every 10 kg of crude ammonium perrhenate, add approximately 30 kg of demineralized water. Use steam to heat it to 80 °C again and keep it for 30 minutes. After filtering through a filter, it is connected to a bucket and cooled naturally. Then, a refrigerator is used to cool the temperature to 2 - 3 °C. After freezing, it is placed in the filter again for filtration. After removing moisture, 95 wt% ammonium perrhenate is formed.

[0025] (4) Put demineralized water into a dissolution kettle and heat it to 80 °C. For every 40 kg of demineralized water, add 10 kg of 95 wt% ammonium perrhenate. At the same time, add 200 ml of 30% hydrogen peroxide, and keep it at 70 - 80 °C in the dissolution kettle and stir for about 60 minutes to ensure that all crystals are dissolved. Filter the solution to obtain a filtrate. Add 0.1 wt% of N,N-dimethylformamide based on the total amount of the filtrate to the filtrate. After the filtrate is cooled to room temperature, place the feed liquid bucket in a freezer to freeze the solution temperature to 2 °C, and filter to obtain crystals. After detection, the product is 99.991% ammonium perrhenate, and the recovery rate of rhenium (based on the raw material waste acid) is 99.1%.

[0026] Example 2

[0027] Same as Example 1, except that in step (4), 300 ml of 30% hydrogen peroxide is added to every 40 kg of demineralized water. After testing, the product is 99.991% ammonium perrhenate, and the recovery rate of rhenium (based on the raw material waste acid) is 98.5%.

[0028] Example 3

[0029] Same as Example 1, except that in step 4, 0.2 wt% of N,N-dimethylformamide is added to the filtrate obtained by filtering the solution, and then crystallization is carried out to obtain crystals. After testing, the product is 99.995% ammonium perrhenate, and the recovery rate of rhenium (based on the raw material waste acid) is 99.2%.

[0030] Example 4

[0031] Same as Example 1, except that in step 4, 0.3 wt% of N,N-dimethylformamide is added to the filtrate obtained by filtering the solution, and then crystallization is carried out to obtain crystals. After testing, the product is 99.991% ammonium perrhenate, and the recovery rate of rhenium (based on the raw material waste acid) is 99.0%.

[0032] Comparative Example 1

[0033] Same as Example 1, except that in step (4), hydrogen peroxide is not added. After testing, the product is 99.3% ammonium perrhenate, and the recovery rate of rhenium (based on the raw material waste acid) is 98.3%.

[0034] Comparative Example 2

[0035] Same as Example 1, except that in step (4), 200 ml of 30% hydrogen peroxide and 300 ml of 25% ammonia water are added to every 40 kg of demineralized water. After testing, the product is 99.75% ammonium perrhenate, and the recovery rate of rhenium (based on the raw material waste acid) is 98.1%.

[0036] The specific embodiments of the present invention disclosed above are only for illustration, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the above-mentioned claims.

Claims

1. A method for extracting high-purity rhenium from copper smelting waste acid, characterized in that: The method comprises the following steps: (1) taking waste acid from copper smelting and pumping the waste acid into a filter using an acid-resistant pump to remove solid particles in the waste acid; (2) The filtered waste acid is pumped into a cation exchange resin column for adsorption using an upper liquid pump. After saturation, the ion exchange column is cleaned with desalted water, and then analyzed with ammonia water. After analysis, it is pumped into a decomposition liquid tank, and then pumped to an evaporator for reduced pressure evaporation. After evaporation, a refrigerator is used to cool the temperature to 1-4°C, and then placed on a filter plate for filtration. After filtration, crude ammonium rhenate is obtained; (3) Pour the crude ammonium rhenate into a recrystallization axe, add 25-35 kg of desalted water for every 10 kg of crude ammonium rhenate, use steam to heat it again to 75-85°C and keep it for 20-40 minutes, filter it through a filter, put it into a barrel to cool naturally, start a refrigerator to cool it to 2-3°C, freeze it, put it into a filter again to filter it, and after removing the water, form crude ammonium rhenate; (4) placing desalted water in a dissolving kettle, heating it to 75-85° C., adding 8-12 kg of crude ammonium rhenate for every 40 kg of desalted water, and simultaneously adding 0.1-0.3 wt % of hydrogen peroxide in the amount of desalted water without adding any other ingredients, and keeping the temperature at 70-80° C. in the dissolving kettle and stirring so that all the crystals are dissolved, filtering the solution to obtain a filtrate, adding 0.08-0.3 wt % of N,N-dimethylformamide in the amount of the total filtrate, and after the filtrate cools to room temperature, placing the feed liquid barrel in a freezer to freeze the solution, cooling the solution temperature to 1-3° C., and filtering to obtain the final product, ammonium rhenate crystals, wherein the purity of the ammonium rhenate crystals is above 99.99%.

2. The method according to claim 1, characterized in that In the step (4), 0.12-0.18 wt% of hydrogen peroxide is added to the desalted water.

3. The method according to claim 1, characterized in that In the step (4), the solution is filtered and 0.18-0.22 wt % of N,N-dimethylformamide is added to the filtrate.

4. The method according to claim 1, characterized in that In the step (1), the acid solution contains 3-4 g / L Cu, 60-70 mg / L Re, and 20-30 g / L sulfuric acid.

5. The method according to claim 3, characterized in that: The purity of the ammonium rhenate crystal is above 99.995%.