Method for selectively recovering Re element from solid waste containing Re element
Through the method of potassium salt roasting, water immersion and cooling precipitation, rhenium is efficiently recovered from solid waste, solving the problems of low leaching rate, large reagent consumption and environmental pollution in the prior art, and achieving high purity, low cost and environmentally friendly Re recycling effects.
Patent Information
- Application Number
- CN202411619166.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-02-25
AI Technical Summary
In the prior art, when recycling rhenium (Re) elements from solid waste, there are problems such as low leaching rate, high reagent consumption, low product purity and environmental pollution.
The potassium salt roasting-water immersion-cooling precipitation method is used to selectively recover from solid waste containing Re elements. By thoroughly mixing the solid waste with the potassium salt and then roasting, a potassium salt calcination residue is obtained, and then precipitated in the water immersion liquid by cooling and precipitation, efficient recovery of Re is achieved.
The leaching rate of Re is achieved >99%, the leaching rate of other metals is <0.1%, the reagent consumption is low, the product is high purity, and no high-salt wastewater is produced, and it is environmentally friendly.
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Figure CN119506625A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical fields of secondary resource recovery, comprehensive utilization of solid waste and nonferrous metal metallurgy, and in particular relates to a method for selectively recovering Re elements in solid waste. Background Art
[0002] Rhenium (Re) is a rare metal that is widely used in catalysts, especially in reforming catalysts in the petrochemical industry, due to its excellent catalytic performance and thermal stability. However, my country's rhenium resources are scarce and mainly rely on imports, with high market prices. The recycling of rhenium resources in waste catalysts is particularly important, which is conducive to protecting my country's strategic metal security and environmental safety.
[0003] At present, there are many rhenium-containing catalysts on the market. These catalysts are generally composed of rhenium and other metals (such as platinum and palladium). In the reforming process, rhenium not only improves the catalytic activity, but also prolongs the service life of the catalyst. According to relevant research, the rhenium content in spent reforming catalysts is usually between 0.1% and 1%.
[0004] At present, the recovery of rhenium mainly relies on chemical methods. These methods generally include steps such as dissolution, precipitation and extraction. In actual operation, common rhenium recovery methods include: (1) Complete dissolution method: Mix the waste catalyst with a strong acid (such as sulfuric acid, hydrochloric acid, etc.) and a strong base (such as sodium hydroxide, etc.), and dissolve all the waste catalyst in the solution. This method is simple and efficient, but it will lead to complex metal types in the solution, making the subsequent metal separation process complicated and difficult to completely separate, reducing the efficiency of rhenium recovery. (2) Active component dissolution method: Use a solvent to selectively leach the active components in the waste catalyst, leaving the substrate in the leaching residue. This method can effectively reduce the difficulty of metal separation, but the metal leaching rate is low.
[0005] The main methods for separating Re from other metals in solution are: (1) Extraction method: Use organic solvents to extract rhenium from the solution. This method has the advantage of strong selectivity, but it is expensive and requires wastewater treatment. (2) Electrochemical method: Reduction of rhenium by electrolysis to recover rhenium metal. Although this method is theoretically feasible, it still faces technical and cost challenges in practical applications. (3) Precipitation method: Add salts such as ammonium chloride and sodium sulfide that can precipitate with ReO-4 to the solution to selectively precipitate the Re element. This method is simple and efficient, but the purity of its product is low and needs to be further purified by recrystallization and other methods.
[0006] At present, the main method for recovering Re from waste catalysts containing Re is roasting-acid leaching. For example, Li Hongmei et al. (Li Hongmei, Zhao Jincheng, Xiong Qingfeng, et al. A method for recovering platinum and rhenium from failed alumina-based platinum-rhenium catalysts [P]. Yunnan Province: CN201810116294.2, 2020-02-21.) used a roasting-acid leaching-resin adsorption-desorption-electrodeposition Re process to recover Pt and Re from waste reforming catalysts. Although the recovery rates of Pt and Re are high, the reagent consumption is large, and the electrochemical deposition method still faces technical and cost challenges. Yang Quan et al. (Yang Quan, Tan Mingliang, Guan Youxiang, et al. A method for recovering high-carbon platinum-rhenium reforming waste catalyst [P]. Hunan Province: CN201610991091.9, 2018-04-06.) obtained a leachate by oxidative acid leaching, used Na2S precipitation to obtain platinum-rhenium enriched slag, and then selectively leached Re by reduction leaching to purify it. This method is simple to operate, but the reagent consumption is large, and it needs to go through multiple recrystallization purification processes to obtain a high-purity product. Summary of the invention
[0007] The present invention provides a method for selectively recovering Re element from solid waste containing Re element, the purpose of which is to solve the problem of green, efficient and economical recovery of useful metal Re in solid waste, so that the Re leaching rate is greater than 99%, and more than 99.5% of the solid waste is enriched in the leaching residue.
[0008] The present invention provides a method for selectively recovering Re from solid waste containing Re, characterized in that the solid waste containing Re includes but is not limited to waste catalysts, waste alloys, waste electrical components, etc., and the Re content is 0.01-10 wt%. The steps of recovering Re are as follows:
[0009] (1) fully mixing potassium salt and solid waste powder, and then roasting at 300-800°C to obtain potassium salt roasting slag;
[0010] (2) adding water to the potassium salt roasting slag obtained in step (1) at a liquid-to-solid ratio of 10:1 to 1:1, heating to 50 to 120° C., leaching at 1 to 10 atmospheres for 0.5 to 5 hours, filtering to obtain water-leached slag and water-leached liquid;
[0011] (3) Lowering the temperature of the water extract obtained in step (2); as the temperature gradually decreases, the solubility of KReO4 gradually decreases and KReO4 precipitates out, and filtering to obtain pure KReO4 precipitate and a water extract containing a small amount of impurities.
[0012] Furthermore, the potassium salt in step (1) may be one or more of potassium chloride, potassium carbonate, potassium chlorate, potassium chlorite, potassium sulfate, potassium nitrate, and potassium acetate.
[0013] Furthermore, the calcination process in step (1) can be enhanced using a microwave field.
[0014] Furthermore, in the step (1), the mass ratio of the potassium salt to the solid waste powder is 0:1 to 1:100.
[0015] Furthermore, during the roasting process of step (1), air or oxygen may be introduced to perform oxidative roasting.
[0016] Furthermore, the potassium salt may be replaced by one or more of other metal salts such as sodium salt and calcium salt.
[0017] Furthermore, the sodium salt comprises one or more of sodium chloride, sodium carbonate, sodium hydroxide, sodium sulfate, sodium nitrate, and sodium acetate, and the calcium salt comprises one or more of calcium chloride, calcium oxide, calcium hydroxide, calcium carbonate, and calcium sulfate.
[0018] Furthermore, the leaching process in step (2) can be enhanced using an ultrasonic field or a microwave field.
[0019] Furthermore, after the potassium salt in step (1) is replaced by one or more other metal salts such as sodium salts and calcium salts, the process of KReO4 precipitation in step (3) must be carried out by adding potassium salts or ammonium salts.
[0020] K + In low temperature aqueous solution, NH+ 4 ions can combine with ReO- 4 ions to form a precipitate. If it is directly roasted with potassium salt, it will be soaked in water to obtain a precipitate containing K + and ReO-4 ions can directly generate KReO4 precipitate after cooling; while after the sodium salt and calcium salt are roasted, the water extract only contains ReO-4 and cannot directly generate KReO4 precipitate, so potassium salt and ammonium salt need to be added to the water extract.
[0021] In addition, ammonium salt cannot be used directly for roasting because the decomposition temperature of NH+ 4 and NH4ReO4 is low. After roasting and water immersion, the content of NH+ 4 is very low, and NH4ReO4 precipitation will not be directly generated after cooling.
[0022] If potassium salt is used directly for roasting, KReO4 can be precipitated directly after the water extract temperature is lowered; if sodium salt or calcium salt is used for roasting, potassium salt or ammonium salt needs to be added to the water extract to precipitate the Re element in the water extract to generate KReO4 or NH4ReO4 products.
[0023] The amount of potassium salt and ammonium salt added should be determined according to the concentration of Re in the water leaching solution, because the water leaching solution is recycled, and the Re element will not be lost even if it is not completely precipitated. +The concentration of NH+ 4 in the water leaching solution is 0.5 to 10 times the concentration of ReO- 4 (preferably 2 to 5 times). Within a certain range, the higher the cation concentration, the better the Re recovery effect.
[0024] Furthermore, after the precipitation process of KReO4 is carried out by adding potassium salt or ammonium salt, the potassium salt may be one or more of potassium chloride, potassium carbonate, potassium chlorate, potassium chlorite, potassium sulfate, potassium nitrate, and potassium acetate; the ammonium salt may be one or more of ammonium chloride, ammonium sulfate, ammonium carbonate, and ammonia water.
[0025] The method for selectively recovering Re from solid waste containing Re provided by the present invention has low reagent consumption, and the appropriate amount of potassium salt added is calculated by the content of Re, which effectively reduces the reagent consumption, and makes the leaching rate of Re greater than 99%, and the leaching rates of other metals less than 0.1%. At the same time, according to the concentration of Re in the leachate and the different solubility of KReO4 at different temperatures, the liquid-solid ratio is adjusted, and the selective crystallization of Re can be easily achieved to improve the recovery rate of Re.
[0026] Principle of the invention: The solubility of KReO4 solid varies greatly at different temperatures. At 0°C, 0.36 g can be dissolved in every 100g of water, and when the temperature rises to 50°C, 3.3 g can be dissolved. When potassium salt is roasted, part of the Re element in the solid waste is oxidized to Re2O7, and the other part of the mineral phase is reconstructed into KReO4. Both substances are soluble in hot water. After high-temperature water immersion, the solution contains a large amount of K + , ReO- 4, the contents of other ions are low, lowering the water immersion temperature to 0 ° C, the solubility of KReO4, K sp Rapidly decrease, precipitate a large number of KReO4 crystals, and K + The higher the concentration, the more Re can be recovered, and the water solution can be recycled, so all Re can be recovered.
[0027] According to the above principle, solid wastes after oxidation roasting and sodium salt roasting can convert Re into Re2O7 or perrhenate salt. Both substances are easily soluble in water, and the water extract contains less other impurity ions. According to the precipitation-dissolution equilibrium theory, when the temperature is constant, c(K + )·c(ReO- 4) is a constant. At this time, in order to realize the precipitation recovery of Re, potassium salt can be added to the low-temperature water leaching solution to increase the K content of the solution. + Therefore, the second method in this invention is to add potassium salt to the water leaching solution to achieve selective recovery of Re.
[0028] The key points of the present invention are:
[0029] The method for selectively recovering Re from solid waste containing Re provided by the present invention belongs to the pyrometallurgical-wet metal combined recovery process. The difficulty of separating multiple metals in the leachate is reduced by selectively leaching Re and crystallizing Re to recover Re, thereby obtaining a high-purity KReO4 product. The leachate can be reused in the leaching process after filtration, and the whole process does not produce any high-salt wastewater, which is environmentally friendly.
[0030] The "potassium salt roasting-water leaching-cooling precipitation" proposed in the present invention is a process for selectively and efficiently recovering Re from solid waste. The roasting temperature is low, and the phase changes of other substances except the Re element are small during the process, and the Re element will not be leached out by water, so that the Re recovery rate is high and the product purity is high; the water leaching temperature is low, and no wastewater is generated in the process, the energy consumption is low, and it is environmentally friendly; there is no need to add potassium salt for the second time during cooling precipitation, and the reagent consumption is small. The present invention is a simple, efficient and environmentally friendly method for recovering the Re element from solid waste. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 It is a flow chart of the present invention;
[0032] Figure 2 The XRD diagram of the KReO4 product obtained by recovering the Re element from the waste reforming catalyst using the method of the present invention is shown in FIG. DETAILED DESCRIPTION
[0033] The method of the present invention is further described below in conjunction with examples. The examples of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention.
[0034] Example 1
[0035] (1) Weigh 15 g of Re-containing spent catalyst powder, mix thoroughly with 5 g of potassium chloride powder, put into a 50 mL corundum crucible, place in a muffle furnace, and calcine at 700 °C for 2 h to obtain 19.6 g of potassium salt calcined slag.
[0036] (2) Weigh 15 g of potassium salt roasting slag and place it in a 100 mL polytetrafluoroethylene liner reactor, add 50 mL of deionized water, tighten the reactor and leach at 90 °C for 1 hour. After the reaction is completed, filter to obtain 13.4 g of water-leached slag and 50 mL of water-leaching liquid, in which the concentration of Re in the water-leaching liquid is 0.986 g / L.
[0037] (3) Transfer the hot water extract to a 100 mL beaker and stir with a glass rod to allow it to cool down slowly. After it cools to room temperature, place the beaker in a refrigerator for 5 hours.
[0038] (4) Filter the water extract refrigerated for 5 hours in step (3) to obtain 0.075 g of pure KReO4 product. The water extract can be recycled for water immersion experiments.
[0039] (5) The KReO4 product obtained in step (4) was placed in a 100 mL beaker, 50 mL of deionized water was added, and the temperature was slowly increased. After the KReO4 was completely dissolved, the solution temperature was slowly lowered to room temperature, and then placed in a refrigerator for 5 hours to perform a recrystallization purification process of the KReO4 product. After filtration, the recrystallized and purified KReO4 product was obtained.
[0040] Example 2
[0041] (1) Weigh 20 g of Re-containing spent catalyst powder, mix thoroughly with 5 g of sodium chloride powder, put into a 50 mL corundum crucible, place in a muffle furnace, and calcine at 500 °C for 3 h to obtain 24.2 g of sodium salt calcined slag.
[0042] (2) Weigh 20 g of sodium salt roasted slag and place it in a 100 mL polytetrafluoroethylene liner reactor, add 50 mL of deionized water, tighten the reactor and leach at 80 °C for 1 hour. After the reaction is completed, filter to obtain 18.6 g of water-leached slag and water-leaching liquid, where the concentration of Re in the water-leaching liquid is 0.974 g / L.
[0043] (3) Place the hot water extract in a 100 mL beaker and allow it to cool slowly. After it cools to room temperature, add 20 mL of 3 mol / L potassium chloride solution to the beaker. Use a glass rod to stir slowly during the addition process. After standing for 2 hours, a turbid extract is obtained.
[0044] (4) Filter the turbid leachate in step (3) to obtain 0.070 g of pure KReO4 product.
[0045] (5) The KReO4 product obtained in step (4) was placed in a 100 mL beaker, 20 mL of deionized water was added, and the temperature was slowly increased. After the KReO4 was completely dissolved, the solution temperature was slowly lowered to room temperature, and then placed in a refrigerator for 5 hours to perform a recrystallization purification process for the KReO4 product. After filtration, the recrystallized and purified KReO4 product was obtained.
Claims
1. A method for selectively recovering Re from solid waste containing Re, characterized in that: The solid waste containing Re element includes but is not limited to waste catalyst, waste alloy, waste electrical components, and the Re content is 0.01-10 wt%; the steps of Re element recovery are as follows: (1) fully mixing potassium salt and solid waste powder, and then roasting at 300-800°C to obtain potassium salt roasting slag; (2) adding water to the potassium salt roasting slag obtained in step (1) at a liquid-to-solid ratio of 10:1 to 1:1, heating to 50 to 120°C, leaching at 1 to 10 atmospheres for 0.5 to 5 hours, filtering to obtain water-leached slag and water-leached liquid; (3) Lowering the temperature of the water extract obtained in step (2); as the temperature gradually decreases, the solubility of KReO4 gradually decreases and KReO4 precipitates out, and filtering to obtain pure KReO4 precipitate and a water extract containing a small amount of impurities.
2. A method for selectively recovering Re from solid waste containing Re according to claim 1, characterized in that: The potassium salt in step (1) is one or more of potassium chloride, potassium carbonate, potassium chlorate, potassium chlorite, potassium sulfate, potassium nitrate and potassium acetate.
3. The method for selectively recovering Re from solid waste containing Re according to claim 1, characterized in that: The calcination process in step (1) is enhanced by using a microwave field.
4. The method for selectively recovering Re from solid waste containing Re according to claim 1, characterized in that: In step (1), the mass ratio of potassium salt to solid waste powder is 0:1 to 1:
100.
5. The method for selectively recovering Re from solid waste containing Re according to claim 1, characterized in that: The roasting process of step (1) can be carried out by introducing air or oxygen for oxidative roasting.
6. A method for selectively recovering Re from solid waste containing Re according to claims 1 and 2, characterized in that: The potassium salt may be replaced by one or more of other metal salts such as sodium salt and calcium salt.
7. The method for selectively recovering Re from solid waste containing Re according to claim 6, characterized in that: The sodium salt includes one or more of sodium chloride, sodium carbonate, sodium hydroxide, and sodium sulfate; the calcium salt includes one or more of calcium chloride, calcium oxide, calcium hydroxide, and calcium carbonate.
8. The method for selectively recovering Re from solid waste containing Re according to claim 1, characterized in that: The leaching process in step (2) is enhanced by using an ultrasonic field or a microwave field.
9. The potassium salt according to claim 1 can be replaced by one or more of other metal salts such as sodium salt and calcium salt, characterized in that: The precipitation of KReO4 in step (3) must be carried out by adding potassium salt or ammonium salt; it is necessary to ensure that K + The concentration of NH+ 4 in the water extract is 0.5 to 10 times that of ReO- 4.
10. The process of KReO4 precipitation according to claim 1 or 9 must be carried out by adding potassium salt or ammonium salt, characterized in that: The potassium salt is one or more of potassium chloride, potassium carbonate, potassium chlorate, and potassium chlorite; the ammonium salt is one or more of ammonium chloride, ammonium sulfate, ammonium carbonate, and ammonia water.