A method for extracting high-purity rhenium from copper smelting spent acid

Abstract

The application discloses a method for extracting high-purity rhenium from copper smelting waste acid, and is characterized in that the method comprises the following steps: (1) removing solid particles in the waste acid through filtration; (2) obtaining crude ammonium rheniate through ion exchange of the filtered waste acid; (3) pouring the crude ammonium rheniate into a recrystallization kettle to perform recrystallization to form crude ammonium rheniate; and (4) adding hydrogen peroxide to the crude ammonium rheniate to perform recrystallization to obtain ammonium rheniate crystals. Through a large number of experimental researches, it is found that a small amount of hydrogen peroxide and N, N-dimethylformamide can be added in the recrystallization process to obtain high-purity ammonium rheniate, and the recovery rate of rhenium is also significantly improved.

Description

Technical Field

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

[0002] Rhenium is a very scarce and ever-appreciating rare metal, its abundance in the Earth's crust second only to protactinium and radium. It is widely used in modern industry, primarily as a catalyst in the petroleum and automotive industries, a petroleum reforming catalyst, and in rhenium alloys for the electronics and aerospace industries. Rhenium plays a role in modern industry that cannot be replaced by other metals. In copper raw materials, rhenium mostly exists in the forms CuReS4 and ReS2. During copper matte smelting, it is completely oxidized to Re2O7. When the SO2 concentration is high, some Re2O7 is reduced to ReO3 and ReO2. Under the smelting atmosphere, almost all rhenium oxides enter the flue gas. After cooling, a small amount enters the flue gas dust, while approximately 85% of the rhenium reacts with water during flue gas purification and washing to form perrhenic acid, which enters the waste acid. Currently, the rhenium content in waste acid and waste liquid from copper smelting enterprises is generally above 1 mg / L. In order to increase the concentration of rhenium in waste acid, some copper smelting enterprises return the sulfide slag obtained after waste acid treatment to the smelting process, which can result in a rhenium content in waste acid and waste liquid exceeding 40 mg / L.

[0003] Chinese invention patent application CN107460320A discloses a novel process for recovering rhenium from waste acid in copper smelting. The process involves pretreatment, centrifugal extraction, centrifugal washing, centrifugal back-extraction, concentration, freeze crystallization, and recrystallization to recover valuable rhenium from the waste acid, thereby obtaining high-purity ammonium rheniumate. Furthermore, the entire process can be automatically controlled online using a PLC. However, this method only yields ammonium rheniumate with a purity of 99.95% after the recrystallization step.

[0004] Chinese patent CN105384195B discloses a method for recovering rhenium from waste acid in molybdenum smelting. The method includes: 1) filtering the waste acid from molybdenum smelting, and adsorbing the filtrate onto a column of a composite aminoethylene-based weakly basic anion exchange resin until adsorption saturation; 2) after adsorption saturation, desorbing with ammonia, collecting the eluent, and evaporating and crystallizing to obtain ammonium perrhenate. The composite aminoethylene-based weakly basic anion exchange resin exhibits a large saturation adsorption capacity for rhenium, resulting in a rhenium content in the eluent that is more than 100 times richer than in the waste acid. Furthermore, it achieves a higher rhenium recovery rate (over 98%) compared to existing extraction and ion exchange methods. Simultaneously, utilizing the solubility differences between ammonium perrhenate, ammonium molybdate, and ammonium sulfate, evaporation and crystallization are used to purify ammonium perrhenate, yielding a purity of over 99.9%. However, this method requires the addition of at least 1% hydrogen peroxide and at least 1% ammonia during the evaporation and crystallization process, inevitably increasing operating costs.

[0005] Furthermore, Chinese patent CN105969985B discloses a method for the comprehensive recovery of rhenium and copper from copper smelting waste acid. This method involves filtering the copper smelting waste acid to remove lead, then targeting rhenium precipitation to obtain rhenium-rich slag. The rhenium-rich slag is then subjected to hot-press oxidative leaching to obtain a rhenium-rich leachate. After evaporation and concentration, the rhenium concentration is 10 g / L-20 g / L. This leachate is then subjected to KCl precipitation and recrystallization to obtain potassium perrhenate. The rhenium-precipitated leachate is then subjected to sulfidation to precipitate copper. However, in this patent, the recrystallization target is potassium perrhenate, requiring the additional addition of KCl to precipitate rhenium, thus increasing costs.

[0006] Chinese invention patent CN 119038611 A discloses a method for purifying ammonium peroxide. This method includes primary dissolution and crystallization, secondary dissolution and crystallization, resin preheating, ion exchange, resin washing of rhenium, resin regeneration, resin acid washing, and neutralization and filtration of ammonium peroxide. In the secondary dissolution and crystallization step, hydrogen peroxide is added at 1.2-1.8% by mass of the ammonium peroxide crystals for oxidation. By controlling the amount of hydrogen peroxide added, not only is the obtained ammonium peroxide of good color, but the purity of the purified ammonium peroxide can also reach over 99.995%, indicating good purification effect. However, this patent application requires the addition of a relatively large amount of hydrogen peroxide for oxidation and further purification via 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 remains a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

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

[0009] This invention relates to a method for extracting high-purity rhenium from waste acid in copper smelting, comprising the following steps:

[0010] (1) Take the waste acid from copper smelting and pump it into the filter using an acid-resistant pump to remove solid particles from the waste acid.

[0011] (2) The filtered waste acid is pumped into the anion exchange resin column for adsorption using an upper liquid pump. After adsorption saturation, the ion exchange column is washed with deionized water and then desorbed with ammonia water. After desorption, the solution is pumped into the desorption tank and then pumped into the evaporator for vacuum evaporation. After evaporation, the temperature is cooled to 1-4℃ using a refrigeration unit and then placed in a suction filter plate for filtration. After filtration, crude ammonium perrhenate is obtained.

[0012] (3) Pour crude ammonium perrylate into a recrystallization kettle. Add 25-35 kg of deionized water for every 10 kg of crude ammonium perrylate. Reheat the mixture with steam to 75-85℃ and maintain for 20-40 minutes. After filtering through a filter, transfer the mixture to a bucket and allow it to cool naturally. Then, use a freezer to cool it to 2-3℃. After freezing, filter it again to remove moisture and form crude ammonium perrylate.

[0013] (4) Place the demineralized water into a dissolving vessel and heat it to 75-85℃. Add 8-12 kg of crude ammonium perrhenate for every 40 kg of demineralized water. At the same time, add 0.1-0.3 wt% of hydrogen peroxide, and do not add any other components. Keep the dissolving vessel at 70-80℃ and stir until all the crystals are dissolved. Filter the solution to obtain filtrate. Add 0.08-0.3 wt% of N,N-dimethylformamide, and after the filtrate cools to room temperature, put the liquid container into a freezer to freeze the solution to 1-3℃. Filter to obtain ammonium perrhenate crystals.

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

[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, followed by crystallization to obtain crystals. In this preferred embodiment, the purity and recovery rate of ammonium perrylate crystals can be further improved.

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

[0017] In a preferred embodiment of the present invention, the purity of the ammonium perrylate crystal is 99.99% or higher; preferably 99.995% or higher.

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

[0019] Through extensive experimental research, this invention has discovered that adding a small amount of hydrogen peroxide and N,N-dimethylformamide during the recrystallization process can yield high-purity ammonium rhenium, while also significantly improving the rhenium recovery rate. Detailed Implementation

[0020] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following preferred embodiments are used to describe in detail the specific implementation methods, technical solutions, features and effects of the present invention.

[0021] Example 1

[0022] (1) Take the waste acid from copper smelting and perform component analysis. The results showed that the acid contained 3.5 g / L Cu, 65 mg / L Re, and 25.3 g / L sulfuric acid. Use an acid-resistant pump to pump the waste acid into a filter to remove solid particles from the waste acid.

[0023] (2) The filtered waste acid is pumped into the anion exchange resin column for adsorption using an upper liquid pump. After adsorption saturation, the ion exchange column is washed with deionized water and then desorbed with ammonia water. After desorption, the solution is pumped into the desorption tank and then pumped into the evaporator at 0.2 MPa to evaporate the steam. After evaporation, the refrigeration unit is turned on to cool it down to 2-3℃. Then it is placed in the suction filter plate for filtration. After filtration, crude ammonium perrylate is obtained.

[0024] (3) Pour crude ammonium perrhenate into a recrystallization kettle. Add about 30 kg of deionized water for every 10 kg of crude ammonium perrhenate. Reheat to 80°C with steam and keep for 30 minutes. After filtering through a filter, transfer to a bucket and let it cool naturally. Then, use a freezer to cool it down to 2-3°C. After freezing, put it back into the filter to remove moisture and form 95 wt% ammonium perrhenate.

[0025] (4) Place the demineralized water into a dissolving vessel and heat it to 80°C. Add 10 kg of 95 wt% ammonium rhenium per 40 kg of demineralized water, along with 200 ml of 30% hydrogen peroxide. Maintain the temperature in the dissolving vessel at 70–80°C and stir for approximately 60 minutes to ensure complete dissolution of the crystals. Filter the solution to obtain a filtrate. Add 0.1 wt% N,N-dimethylformamide to the filtrate. After the filtrate cools to room temperature, place the container in a freezer to freeze the solution until the temperature drops to 2°C. Filter again to obtain crystals. Testing showed that the product was 99.991% ammonium rhenium per 40 kg of demineralized water, with a rhenium recovery rate (based on the raw material waste acid) of 99.1%.

[0026] Example 2

[0027] Similar to Example 1, except that in step (4), 300 ml of 30% hydrogen peroxide was added for every 40 kg of demineralized water. The product was tested and found to be 99.991% ammonium rhenium, with a rhenium recovery rate (based on raw material waste acid) of 98.5%.

[0028] Example 3

[0029] Similar to Example 1, except that in step 4, 0.2 wt% N,N-dimethylformamide was added to the filtrate obtained from the filtered solution, followed by crystallization to obtain crystals. Testing showed that the product was 99.995% ammonium rheniumate, with a rhenium recovery rate (based on the raw material waste acid) of 99.2%.

[0030] Example 4

[0031] Similar to Example 1, except that in step 4, 0.3 wt% N,N-dimethylformamide was added to the filtrate obtained from the filtered solution, followed by crystallization to obtain crystals. Testing showed that the product was 99.991% ammonium rheniumate, with a rhenium recovery rate (based on the raw material waste acid) of 99.0%.

[0032] Comparative Example 1

[0033] Similar to Example 1, except that hydrogen peroxide is not added in step (4). Testing showed that the product was 99.3% ammonium rhenium, with a rhenium recovery rate (based on the raw material waste acid) of 98.3%.

[0034] Comparative Example 2

[0035] Similar to Example 1, the difference lies in step (4), where 200 ml of 30% hydrogen peroxide and 300 ml of 25% ammonia are added to every 40 kg of demineralized water. Testing revealed that the product is 99.75% ammonium rheniumate, with a rhenium recovery rate (based on the raw material waste acid) of 98.1%.

[0036] The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the above claims.

Claims

1. A method for extracting high-purity rhenium from waste acid in copper smelting, characterized in that, The method includes the following steps: (1) Take copper smelting waste acid and use an acid-resistant pump to pump the waste acid into a filter to remove solid particles from the waste acid. (2) The filtered waste acid is pumped into the anion exchange resin column for adsorption using an upper liquid pump. After adsorption saturation, the ion exchange column is washed with deionized water and then desorbed with ammonia water. After desorption, the solution is pumped into the desorption tank and then pumped into the evaporator for vacuum evaporation. After evaporation, the temperature is cooled to 1-4℃ using a refrigeration unit and then placed in a suction filter plate for filtration. After filtration, crude ammonium perrhenate is obtained. (3) Pour crude ammonium perrylate into a recrystallization kettle. Add 25-35 kg of deionized water for every 10 kg of crude ammonium perrylate. Reheat the mixture with steam to 75-85℃ and maintain for 20-40 minutes. After filtering through a filter, transfer the mixture to a bucket and allow it to cool naturally. Then, use a freezer to cool it to 2-3℃. After freezing, filter it again to remove moisture and form crude ammonium perrylate. (4) Place the demineralized water into a dissolving vessel and heat it to 75-85℃. Add 8-12 kg of crude ammonium perrhenate for every 40 kg of demineralized water. At the same time, add 0.1-0.3 wt% hydrogen peroxide of the amount of demineralized water and do not add any other components. Keep the dissolving vessel at 70-80℃ and stir until all the crystals are dissolved. Filter the solution to obtain filtrate. Add 0.08-0.3 wt% N,N-dimethylformamide of the total amount of filtrate. After the filtrate cools to room temperature, put the liquid container into a freezer to freeze the solution to a temperature of 1-3℃. Filter to obtain the final product, ammonium perrhenate crystals. The purity of the ammonium perrhenate crystals is above 99.99%.

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

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

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

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