Method for recovering rhenium from rhenium-containing alloy waste

Abstract

The invention relates to a method for recovering rhenium from rhenium-containing alloy waste. The method specifically comprises the following steps: S1, carrying out acid washing on the rhenium-containing alloy waste; s2, the rhenium-containing alloy waste washed in the step S1 is placed in a rotational flow electrolytic bath to be subjected to electrochemical decomposition till the mass volume concentration of rhenium in electrolyte is not smaller than 25 g / L; wherein the electrolyte is a mixed aqueous solution of NH4Cl and NH4OH; s3, the electrolyte obtained in the step S2 is placed in a refrigerated centrifuge to be refrigerated and centrifuged, and ammonium rhenate crystals with the uniform particle size are formed; and washing with deionized water at 0-2 DEG C to finish the preparation of the high-purity ammonium rhenate. The method is used for separating and extracting rhenium in tungsten-rhenium alloy waste and molybdenum-rhenium alloy waste, the process is short, the production process is high in controlled degree, and the product is high in purity and stable in quality; the rhenium metal recovery rate is high; the tungsten-rhenium and molybdenum-rhenium separation degree is high, the environment-friendly advantage is obvious, and the cost is low.

Description

Technical Field

[0001] The invention relates to the field of metallurgy, and in particular to a method for recovering rhenium from rhenium-containing alloy waste. Background Art

[0002] The mass fraction of rhenium in the earth's crust is only 1×10 -9 , belongs to scattered metals, and there is no independently smeltable rhenium mineral. Due to its excellent properties such as high melting point, high hardness, creep resistance, corrosion resistance and good plasticity, rhenium occupies a very important position in the cutting-edge science fields of chemical industry, metallurgy, aerospace and national defense. Rhenium alloys made of Re as an alloying element are used in the metallurgical industry to achieve the purpose of improving and improving the properties of alloys. The more typical rhenium alloys are: W-Re alloy and Mo-Re alloy. W-Re alloy is a solid solution strengthened alloy composed of W as the matrix and Re element. The typical rhenium content in industrial production is 1wt.%, 3wt.%, 5wt.%, 10wt.%, 25wt.%, and 26wt.%. The rhenium content in Mo-Re alloy is generally 2-50wt.%. The addition of Re can reduce the brittleness and transition temperature of the alloy, and increase the recrystallization temperature of the alloy, so that the alloy has excellent room temperature and high temperature properties. In the process of manufacturing W-Re alloy, Mo-Re alloy, pure Re and other materials into plates, bars and wires, since the yield rate is generally lower than 70%, a lot of scraps and waste products are often produced. The scraps contain a large amount of tungsten, molybdenum and rhenium components, and the valuable metals must be recycled.

[0003] Since the chemical properties of tungsten, molybdenum and rhenium are very similar, the main existing processes for recovering Re from rhenium-containing waste materials include: pyrometallurgical process, hydrometallurgical process, pyrometallurgical-hydrometallurgical combined process and electrochemical metallurgical process.

[0004] Among them, the pyrometallurgical process has a long reaction time, a long reaction time, a lot of dust, waste gas and waste slag, and a recovery rate of 65-95%. The single use of this method to recover rhenium is not economical and has serious environmental pollution. At the same time, the energy consumption is high and the collection of rhenium is relatively complicated; the hydrometallurgical process has a low unit production capacity, high temperature and high energy consumption, rhenium absorption is difficult to control, oxidation and decomposition are not thorough, and the process is long, it is easy to generate waste liquid and waste gas, the energy consumption is high, and the recovery rate is 74-98%; the pyrometallurgical-hydrometallurgical combined metallurgical process has a long process, is easy to generate waste liquid and waste gas, has a large energy consumption, and the recovery rate is 74-98%; the existing electrochemical metallurgical process has poor versatility, is easy to generate a large amount of waste liquid, and the product value is not high. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for recovering rhenium from rhenium-containing alloy waste, which is used for separating and extracting rhenium from tungsten-rhenium alloy waste and molybdenum-rhenium alloy waste. The process is short, the production process is highly controlled, the product purity is high and the quality is stable; the rhenium metal recovery rate is high; the degree of separation of tungsten-rhenium and molybdenum-rhenium is high, and it has obvious environmental advantages and low cost.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for recovering rhenium from rhenium-containing alloy waste, which is specifically carried out according to the following steps:

[0007] S1. Acid washing of the rhenium alloy waste;

[0008] S2, placing the rhenium-containing alloy waste after washing in step S1 in a cyclone electrolytic cell for electrochemical decomposition; as the electrolysis time goes by, the rhenium in the rhenium waste gradually dissolves in the electrolyte until the mass volume concentration of rhenium in the electrolyte is not less than 25g / L; wherein the electrolyte is a mixed aqueous solution of NH4Cl and NH4OH, the mass volume concentration of NH4Cl in the electrolyte is 30-80g / L, and the mass volume concentration of NH4OH in the electrolyte is 10-50g / L;

[0009] S3, placing the electrolyte obtained in step S2 in a refrigerated centrifuge for refrigerated centrifugation to form ammonium rhenate crystals with uniform particle size; washing with 10 to 20 L of 0 to 2° C. deionized water to complete the preparation of high-purity ammonium rhenate.

[0010] Among them, during the cyclonic electrolysis process, the reaction at the anode is:

[0011] W+6OH - -6e=WO4 2- +4H2O

[0012] Re+7OH - -7e=ReO7 - +4H2O

[0013] Mo+6OH - -6e=MoO4 2- +4H2O

[0014] The cathode reaction is:

[0015] 2H2O+2e=H2↑+2OH -

[0016] The hydrolysis reaction of ammonium chloride is:

[0017] 2NH4Cl+2H2O=NH4OH+HCl↑

[0018] Furthermore, in step S1, the acid washing method is specifically as follows: placing the rhenium alloy waste in pickling water, and passing compressed air into the pickling water for cleaning for 10 to 30 minutes; taking out the rhenium alloy waste, and washing it with two-stage deionized water, and passing compressed air for cleaning for 1 to 3 minutes during the cleaning process.

[0019] Furthermore, in step S1, the pickling water is a hydrochloric acid or sulfuric acid aqueous solution with a mass concentration of 1 to 3%.

[0020] Furthermore, in step S2, the anode of the cyclone electrolytic cell is a titanium mesh with a surface coating of titanium oxide; and the cathode is 316L stainless steel.

[0021] Furthermore, in step S2, the voltage of the electrolysis reaction in the cyclone electrolytic cell is 5.0-12.0V, and the current is 800A.

[0022] Furthermore, in step S2, the gas generated by the cyclone electrolysis is introduced into ammonia water with a mass percentage concentration of 8 to 17%, and the absorption liquid after absorption is returned to the cyclone electrolysis cell.

[0023] Furthermore, in step S3, the temperature of the refrigerated centrifuge is -10 to -30°C, and the rotation speed is 800 to 1200 r / min.

[0024] Furthermore, the mother liquor after centrifugation in step S3 and the washing water after washing are transferred to the cyclone electrolytic cell in step S2.

[0025] Furthermore, when the rhenium alloy waste is tungsten-rhenium alloy, the method also includes a tungsten recovery method, and the specific steps are as follows:

[0026] When the tungsten concentration in the mother liquor after the refrigerated centrifugation in step S3 is not less than 50g / L, concentrated hydrochloric acid with a mass percentage concentration of 10-30% is added to the mother liquor to neutralize the (NH4)2WO4 therein until the pH value of the mother liquor is 7-7.5; the mixture is kept warm and stirred for 0.5-1h to stabilize the pH value, and ammonium paratungstate is precipitated. After centrifugal filtration and washing with deionized water, ammonium paratungstate crystals are obtained.

[0027] Among them, the reaction of ammonium paratungstate is as follows:

[0028] 12(NH4)2WO4+14HCl+4H2O=5(NH4)2O·12WO3·11H2O+14NH4Cl

[0029] Furthermore, when the rhenium alloy waste is a molybdenum-rhenium alloy, the method also includes a molybdenum recovery method, and the specific steps are as follows:

[0030] When the molybdenum concentration in the mother liquor after the refrigerated centrifugation in step S3 is not less than 40g / L, concentrated hydrochloric acid with a mass percentage concentration of 10-30% is added to the mother liquor to neutralize the (NH4)2MoO4 therein until the pH value of the mother liquor is 2-3; the process temperature is controlled above 45°C, stirred for 0.5-1h to stabilize the pH, and ammonium tetramolybdate is precipitated. After centrifugal filtration and washing with deionized water, ammonium tetramolybdate crystals are obtained.

[0031] Among them, the reaction of ammonium tetramolybdate is as follows:

[0032] 4(NH4)2MoO4+4HCl+2H2O=(NH4)2Mo4O 13 ·2H2O+4NH4Cl.

[0033] Furthermore, in the tungsten recovery method or the molybdenum recovery method, the filtrate obtained by centrifugal filtration is returned to the cyclone electrolytic cell of step S2 to be used as an electrolyte.

[0034] Advantages of the present invention: The present invention discloses a method for recovering rhenium from rhenium-containing alloy waste, wherein tungsten or molybdenum and rhenium in the waste alloy are simultaneously leached out by cyclone electrolysis to obtain an ammonium salt solution containing tungsten-rhenium or molybdenum-rhenium, and rhenium in the solution is extracted by a one-step method of freezing centrifugation to form ammonium rhenate crystalline solid, thereby realizing the preliminary separation of tungsten and rhenium or molybdenum and rhenium in the mixed ammonium solution; and then an ammonium paratungstate product or an ammonium tetramolybdate product is obtained by acid precipitation, and the acid precipitation mother liquor is returned to the cyclone electrolysis as an electrolyte. The method is suitable for the separation and extraction of tungsten and rhenium in tungsten-rhenium alloy waste, and the separation and extraction of molybdenum and rhenium in molybdenum-rhenium alloy waste. Separation and extraction of rhenium; compared with other existing technologies, the process flow is short, suitable for alloys with complex components, with strong versatility, and there is no problem of rhenium collection during oxidative roasting; the metal recovery rate of tungsten or molybdenum and rhenium is high, the separation coefficient of tungsten-rhenium and molybdenum-rhenium is high, the purity of tungsten or molybdenum products and rhenium products is high, and the product quality is stable; the number of auxiliary materials required is small, and the auxiliary materials are recycled in the process, no wastewater or waste salt is generated, and the environmental protection advantage is obvious; the process flow is short, there is no need to concentrate to increase the concentration of metal elements in the solution, the energy consumption is low, the process is highly controlled, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a process flow chart of a method for recovering rhenium from rhenium-containing alloy waste. DETAILED DESCRIPTION

[0036] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not limit the protection scope of the present invention.

[0037] Embodiment 1

[0038] Reference Figure 1As shown, industrial-grade hydrochloric acid is diluted with deionized water to a mass concentration of 3% and then injected into a pickling tank, a hanging basket containing tungsten-rhenium alloy waste (rhenium content 25%) is placed in the pickling tank, compressed air is introduced into the pickling tank for cleaning for 10 minutes, and then the hanging basket is placed in two-stage deionized water tanks for cleaning, and compressed air is introduced for 1 minute respectively. After the two-stage deionized water cleaning is completed, the hanging basket discharge valve is opened to load the waste into the cyclone electrolytic cell, and a mixed solution with a concentration of 80g / L of NH4Cl and a concentration of 10g / L of NH4OH is injected into the circulation tank, the circulation pump outlet valve is turned to the electrolytic circulation tank, the circulation pump is started, the electrolytic cell voltage is set to 9.0V, the current is 800A, the power of the electrolytic cell is turned on, until the concentration of rhenium in the electrolyte is 27.2g / L, the refrigerated centrifuge is started, the temperature is set to -20°C, and the speed is 1000r / min, and ammonium rhenate crystals with uniform particle size are obtained by refrigerated centrifugation. The ammonium rhenate solid is centrifugally washed with 10 L of 0-2° C. deionized water to obtain high-purity ammonium rhenate.

[0039] According to GDMS-MS test, the purity of ammonium rhenate is greater than 99.99% and the recovery rate of rhenium reaches 99.4%.

[0040] When the tungsten concentration in the filtrate of the frozen centrifuge reaches 78.5g / L, the tungsten-containing filtrate is transferred to the acid precipitation reactor, stirring is started, concentrated hydrochloric acid (wt: 10%) is added to neutralize the (NH4)2WO4 in the filtrate, and when the pH value of the solution is neutralized to 7-7.5, the addition of hydrochloric acid is stopped, and the solution is stirred for 1 hour at a temperature of about 94% of the tungsten in the solution to form APT precipitation, which is centrifuged and filtered, and washed with deionized water to obtain ammonium paratungstate crystals.

[0041] After testing, the purity of ammonium paratungstate crystals is greater than 99.9%, the rhenium content of the product is 8ppm, and the tungsten recovery rate is 99.6%.

[0042] Embodiment 2

[0043] Reference Figure 1As shown, industrial-grade hydrochloric acid is diluted with deionized water to a mass concentration of 2% and then injected into a pickling tank, a hanging basket containing molybdenum-rhenium alloy waste (rhenium content 30%) is placed in the pickling tank, compressed air is introduced into the pickling tank for cleaning for 20 minutes, and then the hanging basket is placed in two-stage deionized water tanks for cleaning, and compressed air is introduced for 2 minutes respectively. After the two-stage deionized water cleaning is completed, the hanging basket discharge valve is opened to load the waste into the cyclone electrolytic cell, and a mixed solution with a concentration of 55g / L of NH4Cl and a concentration of 30g / L of NH4OH is injected into the circulation tank, the circulation pump outlet valve is turned to the electrolytic circulation tank, the circulation pump is started, the electrolytic cell voltage is set to 12.0V, the current is 800A, the power of the electrolytic cell is turned on, until the concentration of rhenium in the electrolyte is 30.2g / L, the refrigerated centrifuge is started, the temperature is set to -10°C, and the speed is 800r / min, and ammonium rhenate crystals with uniform particle size are obtained by refrigerated centrifugation. The ammonium rhenate solid is centrifugally washed with 15L of 0-2°C deionized water to obtain high-purity ammonium rhenate.

[0044] According to GDMS-MS test, the purity of ammonium rhenate is greater than 99.99% and the recovery rate of rhenium reaches 99.6%.

[0045] When the molybdenum concentration in the filtrate of the frozen centrifugation is 65.9 g / L, the molybdenum-containing filtrate is transferred to an acid precipitation reactor, stirring is started, concentrated hydrochloric acid (wt: 10%) is added to neutralize the (NH4)2MoO4 in the filtrate, and when the pH value of the solution is neutralized to 2-2.5, the addition of hydrochloric acid is stopped, the process temperature is controlled within 45° C., and the solution is kept warm and stirred for 1 hour. About 95.5% of the molybdenum in the solution is precipitated as ammonium tetramolybdate, which is centrifugally filtered and washed with deionized water to obtain ammonium tetramolybdate crystals, the purity of the ammonium tetramolybdate crystals is greater than 99.9%, the rhenium content of the product is 6 ppm, and the molybdenum recovery rate reaches 99.5%.

[0046] Embodiment 3

[0047] Reference Figure 1As shown, industrial-grade hydrochloric acid is diluted with deionized water to a mass concentration of 1% and then injected into a pickling tank, a hanging basket containing molybdenum-rhenium alloy waste (rhenium content 30%) is placed in the pickling tank, compressed air is introduced into the pickling tank for cleaning for 30 minutes, and then the hanging basket is placed in two-stage deionized water tanks for cleaning, and compressed air is introduced for 3 minutes respectively. After the two-stage deionized water cleaning is completed, the hanging basket discharge valve is opened to load the waste into the cyclone electrolytic cell, and a mixed solution with a concentration of 30g / L of NH4Cl and a concentration of 50g / L of NH4OH is injected into the circulation tank, the circulation pump outlet valve is turned to the electrolytic circulation tank, the circulation pump is started, the electrolytic cell voltage is set to 8.0V, the current is 800A, the power of the electrolytic cell is turned on, until the concentration of rhenium in the electrolyte is 34.2g / L, the refrigerated centrifuge is started, the temperature is set to -30°C, and the speed is 1200r / min, and ammonium rhenate crystals with uniform particle size are obtained by refrigerated centrifugation. The ammonium rhenate solid is washed by centrifugation with 15L 0-2°C deionized water, and the washing water and the centrifugal filtrate are returned to the cyclone electrolysis circulation tank; thus, high-purity ammonium rhenate is obtained.

[0048] According to GDMS-MS test, the purity of ammonium rhenate is greater than 99.99% and the recovery rate of rhenium reaches 99.8%.

[0049] In the above embodiment, the anode of the cyclone electrolytic cell is a mesh titanium material, the surface coating of the titanium mesh is titanium oxide, the cathode is made of 316L material, the electrolyte is injected into the circulation tank, the outlet of the circulation tank is connected to the inlet of the electrolytic cell through a circulation pump, the water outlet of the electrolytic cell is connected to the inlet of the circulation tank, the other outlet of the circulation pump is connected to the refrigerated centrifuge, the centrifuged mother liquor enters the mother liquor tank, and the mother liquor tank outlet pump is connected to the circulation tank. Turn the outlet valve of the circulation pump to the electrolytic circulation tank, start the circulation pump, and as the electrolysis time goes by, the tungsten, molybdenum, and rhenium in the tungsten-rhenium and molybdenum-rhenium alloy wastes gradually dissolve in the electrolyte.

[0050] The method for recovering rhenium from rhenium-containing alloy waste in the above embodiment is to simultaneously leach tungsten or molybdenum and rhenium in the waste alloy by cyclone electrolysis to obtain an ammonium salt solution containing tungsten-rhenium or molybdenum-rhenium, and extract rhenium in the solution by a one-step method of refrigerated centrifugation to form ammonium rhenate crystalline solid, thereby achieving preliminary separation of tungsten and rhenium or molybdenum and rhenium in the mixed ammonium solution; and then obtain ammonium paratungstate product or ammonium tetramolybdate product respectively by acid precipitation, and the acid precipitation mother liquor is returned to the cyclone electrolysis as an electrolyte. The method is suitable for the separation and extraction of tungsten and rhenium in tungsten-rhenium alloy waste, and the separation of molybdenum and rhenium in molybdenum-rhenium alloy waste. Extraction; compared with other existing technologies, the process flow is short, suitable for alloys with complex components, with strong versatility, and there is no problem of rhenium collection in oxidative roasting; the metal recovery rate of tungsten or molybdenum and rhenium is high, the separation coefficient of tungsten-rhenium and molybdenum-rhenium is high, the purity of tungsten or molybdenum products and rhenium products is high, and the product quality is stable; the required auxiliary materials are few in variety, the auxiliary materials are recycled in the process, no wastewater or waste salt is generated, and the environmental protection advantage is obvious; the process flow is short, there is no need to increase the concentration of metal elements in the solution by concentration, the energy consumption is low, the process is highly controlled, and the cost is low.

[0051] The above embodiments should not limit the present invention in any way, and any technical solutions obtained by equivalent replacement or equivalent conversion shall fall within the protection scope of the present invention.

Claims

1. A method for recovering rhenium from rhenium-containing alloy waste, characterized in that: Follow these steps: S1. Acid washing of the rhenium alloy waste; S2, placing the rhenium alloy waste washed in step S1 in a cyclone electrolytic cell for electrochemical decomposition; As the electrolysis time goes by, the rhenium in the rhenium waste gradually dissolves in the electrolyte until the mass volume concentration of rhenium in the electrolyte is not less than 25 g / L; wherein the electrolyte is a mixed aqueous solution of NH4Cl and NH4OH, the mass volume concentration of NH4Cl in the electrolyte is 30-80 g / L, and the mass volume concentration of NH4OH in the electrolyte is 10-50 g / L; S3, placing the electrolyte obtained in step S2 in a refrigerated centrifuge for refrigerated centrifugation to form ammonium rhenate crystals with uniform particle size; washing with 10 to 20 L of 0 to 2° C. deionized water to complete the preparation of high-purity ammonium rhenate.

2. A method for recovering rhenium from rhenium-containing alloy waste according to claim 1, characterized in that: In step S1, the acid washing method is specifically as follows: using hydrochloric acid or sulfuric acid aqueous solution with a mass concentration of 1 to 3% as pickling water, placing the rhenium-containing alloy waste in the pickling water, and passing compressed air into the pickling water for cleaning for 10 to 30 minutes; taking out the rhenium-containing alloy waste, and washing it with two-stage deionized water, and passing compressed air for cleaning for 1 to 3 minutes during the cleaning process.

3. The method for recovering rhenium from rhenium-containing alloy waste according to claim 1, characterized in that: In step S2, the anode of the cyclone electrolytic cell is a titanium mesh with a surface coating of titanium oxide; the cathode is 316L stainless steel.

4. The method for recovering rhenium from rhenium-containing alloy waste according to claim 1, characterized in that: In step S2, the voltage of the electrolysis reaction in the cyclone electrolytic cell is 5.0-12.0V, and the current is 800A.

5. The method for recovering rhenium from rhenium-containing alloy waste according to claim 1, characterized in that: In step S2, the gas generated by cyclone electrolysis is introduced into ammonia water with a mass percentage concentration of 8-17%, and the absorption liquid after absorption is returned to the cyclone electrolysis cell.

6. A method for recovering rhenium from rhenium-containing alloy waste according to claim 1, characterized in that: In step S3, the temperature of the refrigerated centrifuge is -10 to -30°C, and the rotation speed is 800 to 1200 r / min.

7. A method for recovering rhenium from rhenium-containing alloy waste according to any one of claims 1 to 6, characterized in that: The mother liquor after centrifugation in step S3 and the washing water after washing are transferred to the cyclone electrolytic cell in step S2.

8. The method for recovering rhenium from rhenium-containing alloy waste according to claim 1, characterized in that: When the rhenium alloy waste is tungsten-rhenium alloy, the method also includes a tungsten recovery method, and the specific steps are as follows: When the tungsten concentration in the mother liquor after the refrigerated centrifugation in step S3 is not less than 50g / L, concentrated hydrochloric acid with a mass percentage concentration of 10-30% is added to the mother liquor to neutralize the (NH4)2WO4 therein until the pH value of the mother liquor is 7-7.5; the mixture is kept warm and stirred for 0.5-1h to stabilize the pH value, and ammonium paratungstate is precipitated. After centrifugal filtration and washing with deionized water, ammonium paratungstate crystals are obtained.

9. The method for recovering rhenium from rhenium-containing alloy waste according to claim 1, characterized in that: When the rhenium alloy waste is a molybdenum-rhenium alloy, the method further comprises a molybdenum recovery method, and the specific steps are as follows: When the molybdenum concentration in the mother liquor after the refrigerated centrifugation in step S3 is not less than 40g / L, concentrated hydrochloric acid with a mass percentage concentration of 10-30% is added to the mother liquor to neutralize the (NH4)2MoO4 therein until the pH value of the mother liquor is 2-3; the process temperature is controlled above 45°C, stirred for 0.5-1h to stabilize the pH, and ammonium tetramolybdate is precipitated. After centrifugal filtration and washing with deionized water, ammonium tetramolybdate crystals are obtained.

10. A method for recovering rhenium from rhenium-containing alloy waste according to claim 8 or 9, characterized in that: The filtrate obtained by centrifugal filtration is returned to the cyclone electrolytic cell in step S2 to be used as an electrolyte.

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