阅读说明：本技术 一种从废铑催化剂残渣中回收铑的方法 (Method for recovering rhodium from waste rhodium catalyst residues ) 是由 董岩 李坚 柳颖 安欣 刘玉芬 袁滨 于 2019-08-30 设计创作，主要内容包括：本发明涉及一种从废铑催化剂残渣中回收铑的方法,其包括：将废铑催化剂残渣制成粗氯铑酸溶液后,对所述粗氯铑酸溶液经冷等离子体辉光放电处理,使得所述粗氯铑酸溶液中的铑离子还原形成铑单质。本发明简化了传统回收铑的方法中在对废铑催化剂残渣进行焙烧后的处理过程,回收效率高。而且,本发明采用冷等离子体辉光放电方法对粗氯铑酸溶液中的铑离子进行还原分离,避免引入其它有机溶剂,降低了回收成本。此外,采用本发明方法对废铑催化剂残渣中铑的回收率可高达97％以上,回收铑的纯度可高达99％以上。(The invention relates to a method for recovering rhodium from waste rhodium catalyst residues, which comprises the following steps: after waste rhodium catalyst residues are prepared into a crude chlororhodic acid solution, the crude chlororhodic acid solution is subjected to cold plasma glow discharge treatment, so that rhodium ions in the crude chlororhodic acid solution are reduced to form a rhodium simple substance. The method simplifies the treatment process of the waste rhodium catalyst residue after roasting in the traditional method for recovering rhodium, and has high recovery efficiency. In addition, the invention adopts a cold plasma glow discharge method to carry out reduction separation on rhodium ions in the crude chlororhodic acid solution, avoids introducing other organic solvents and reduces the recovery cost. In addition, the recovery rate of rhodium in the waste rhodium catalyst residue can reach more than 97 percent by adopting the method, and the purity of the recovered rhodium can reach more than 99 percent.)

1. A process for recovering rhodium from a spent rhodium catalyst residue comprising: after waste rhodium catalyst residues are prepared into a crude chlororhodic acid solution, the crude chlororhodic acid solution is subjected to cold plasma glow discharge treatment, so that rhodium ions in the crude chlororhodic acid solution are reduced to form a rhodium simple substance.

2. The method according to claim 1, wherein the method for treating the crude chlororhodic acid solution by cold plasma glow discharge comprises the following steps:

placing a mixed solution formed by mixing the crude chlororhodic acid solution and a surfactant in a plasma discharge gas atmosphere;

under the action of alternating current, rhodium ions in the mixed solution are reduced to form a rhodium simple substance by plasma formed by discharging the plasma discharge gas.

3. The method according to claim 2, wherein the ratio of the molar amount of rhodium ions in the crude chlororhodic acid solution to the mass of the surfactant is 1 (3.5-28.5) mol/g, preferably 1 (5-24) mol/g.

4. A method according to claim 2 or 3, wherein the surfactant comprises polyvinylpyrrolidone and/or polyvinyl alcohol; and/or

The plasma discharge gas includes one or more of an inert gas, nitrogen, and air.

5. The method according to any one of claims 2-4, wherein the voltage of the alternating current is 150-500V, preferably 200-450V; the reduction time is 3-15 min.

6. The method according to any one of claims 1 to 5, wherein the method for producing the crude chlororhodic acid solution from the waste rhodium catalyst residue comprises the steps of:

roasting the waste rhodium catalyst residues to prepare rhodium ash;

and dissolving the rhodium ash in a hydrochloric acid and hydrogen peroxide solution to form the crude chlororhodic acid solution.

7. The method of claim 6, wherein the firing treatment comprises: firstly raising the temperature to a predetermined temperature T₁Is kept for a period of time t₁Then continuously raising the temperature to the roasting temperature T₂Is kept for a period of time t₂；

Preferably, said predetermined temperature T₁At 400 ℃ and 500 ℃ t₁Is 2-3 h; the roasting temperature T₂600 ℃ and 800 ℃ t₂Is 4-6 h.

8. The method of claim 6 or 7, wherein dissolving the rhodium ash in an aqueous solution of hydrochloric acid and hydrogen peroxide to form the crude chlororhodic acid solution comprises:

adding a hydrochloric acid solution to the rhodium ash at a temperature of 60-80 ℃ to form a hydrochloric acid solution comprising rhodium ash;

under the stirring state, dropwise adding hydrogen peroxide solution into the hydrochloric acid solution containing rhodium ash to form a hydrochloric acid and hydrogen peroxide mixed solution containing rhodium ash;

and (3) reacting the mixed solution of hydrochloric acid containing rhodium ash and hydrogen peroxide at the temperature of 90-120 ℃ for 2-4h, and then cooling and filtering to obtain the crude chlororhodic acid solution.

9. The method according to any one of claims 6 to 8, wherein the hydrochloric acid solution is added in an amount of 15 to 18mL/g, preferably 16 to 17mL/g, in terms of the ratio of the volume of the hydrochloric acid solution to the mass of the rhodium ash; and/or

The adding amount of the hydrogen peroxide solution is 1.2-1.8, preferably 1.4-1.6 according to the volume ratio of the hydrogen peroxide solution to the hydrochloric acid solution; and/or

The concentration of the hydrochloric acid solution is 30-37 wt%, and the concentration of the hydrogen peroxide solution is 30-50 wt%.

10. The method as claimed in any one of claims 1 to 9, wherein the content of rhodium ions in the crude chlororhodic acid solution is 2000-3000mg/L, preferably 2041-2987 mg/L.

Technical Field

The invention belongs to the technical field of precious metal recovery, and particularly relates to a method for recovering rhodium from waste rhodium catalyst residues.

Background

Rhodium is used as a noble metal, can be prepared into noble metal homogeneous catalysts such as rhodium-phosphine complexes and the like, and is widely applied due to the advantages of mild conditions, high conversion rate, high positive-to-differential ratio and the like in hydroformylation reaction, but the rhodium catalyst is easy to deactivate due to high reaction temperature, trace impurity poisoning and the like in the reaction process. Because rhodium is expensive, the supply amount of rhodium in China cannot meet the requirement of practical application at present, and therefore, the rhodium recovery has very important value.

The recovery of rhodium mainly comprises two methods, namely an incineration method and a wet method. The incineration method is a method commonly used for purifying precious metals industrially at present. Chinese patent CN1273278A discloses a method for recovering metal rhodium from waste rhodium catalyst raffinate (rhodium-phosphine organic solution), which improves the yield by burning and ashing organic rhodium-containing waste liquid with a certain temperature programming, wherein the yield is generally calculated to be more than 90%. Chinese patent CN107879382B discloses a method for preparing rhodium chloride by recovering rhodium from waste rhodium incineration slag, which comprises the steps of firstly carrying out aerobic high-temperature roasting on waste catalyst roasted rhodium slag without completely removing organic matters to completely remove the organic matters to obtain rhodium ash, then adding hydrofluoric acid and perchloric acid into the rhodium ash to carry out pretreatment, then adding hydrochloric acid and hydrogen peroxide to directly dissolve the rhodium slag, filtering to obtain a crude rhodium acid solution, finally removing other metal ion impurities from the crude rhodium acid solution by adopting an ion exchange method, concentrating and drying to obtain the rhodium chloride hydrate. Although the incineration method has the advantages of simple process, high efficiency and wide application range, the incineration method also has the defects of large environmental pollution, high energy consumption, high requirements on equipment and production operation conditions and the like.

The wet method is mainly used for separating organic matters by methods of oxidation digestion, reduction and the like, and rhodium is greatly lost by adopting an incineration method for some rhodium waste liquid, and in this case, the wet method is usually selected for recovering rhodium. Chinese patent CN101177306A discloses a method for recovering rhodium chloride from waste rhodium catalyst, which comprises digesting waste rhodium catalyst generated by oxo reaction with mixed solution of inorganic acid and oxidant to separate rhodium from organic matter, removing impurities by precipitation, ion exchange and other methods to obtain rhodium chloride, and recrystallizing to obtain hydrated rhodium chloride, wherein the recovery rate of rhodium is more than 97%. Chinese patent CN102373335A discloses a method for recovering rhodium from waste rhodium catalyst of oxo synthesis, which comprises adding oxidant to treat mixed solution, adding hydroxide to obtain rhodium precipitate, filtering, washing, and drying to obtain rhodium. However, the wet process has a long process flow, requires a large amount of organic reagents, has many limitations in the separation process, and cannot be industrialized on a large scale.

In view of the above-mentioned disadvantages of the existing methods for recovering rhodium, there is a problem that research and development of a method for efficiently and environmentally recovering rhodium from waste rhodium catalyst residues is urgently needed.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a method for recovering rhodium from waste rhodium catalyst residues aiming at the defects of the prior art. The method adopts a cold plasma glow discharge method to carry out reduction separation on rhodium ions in the crude chlororhodic acid solution, avoids introducing other organic solvents and reduces the recovery cost. Meanwhile, the invention simplifies the treatment process of the waste rhodium catalyst residue after roasting in the traditional method for recovering rhodium, and has high recovery efficiency.

To this end, the present invention provides a process for recovering rhodium from a spent rhodium catalyst residue comprising: after waste rhodium catalyst residues are prepared into a crude chlororhodic acid solution, the crude chlororhodic acid solution is subjected to cold plasma glow discharge treatment, so that rhodium ions in the crude chlororhodic acid solution are reduced to form a rhodium simple substance.

In some embodiments, the method for subjecting the crude chlororhodic acid solution to a cold plasma glow discharge treatment comprises the steps of:

placing a mixed solution formed by mixing the crude chlororhodic acid solution and a surfactant in a plasma discharge gas atmosphere;

under the action of alternating current, rhodium ions in the mixed solution are reduced to form a rhodium simple substance by plasma formed by discharging the plasma discharge gas.

In some embodiments, the ratio of the molar amount of rhodium ions in the crude chlororhodic acid solution to the mass of the surfactant is 1 (3.5-28.5) mol/g, preferably 1 (5-24) mol/g.

In some embodiments, the surfactant comprises polyvinylpyrrolidone and/or polyvinyl alcohol; and/or

The plasma discharge gas includes one or more of an inert gas, nitrogen, and air.

In some embodiments, the voltage of the alternating current is 150-; the reduction time is 3-15 min.

In some embodiments, the method of making a crude chlororhodic acid solution from waste rhodium catalyst residues comprises the steps of:

roasting the waste rhodium catalyst residues to prepare rhodium ash;

and dissolving the rhodium ash in a hydrochloric acid and hydrogen peroxide solution to form the crude chlororhodic acid solution.

In some embodiments, the method of firing treatment comprises: firstly raising the temperature to a predetermined temperature T₁Is kept for a period of time t₁Then continuously raising the temperature to the roasting temperature T₂Is kept for a period of time t₂；

Preferably, said predetermined temperature T₁At 400 ℃ and 500 ℃ t₁Is 2-3 h; the roasting temperature T₂600 ℃ and 800 ℃ t₂Is 4-6 h.

In some embodiments, a method of dissolving the rhodium ash in an aqueous hydrochloric acid and hydrogen peroxide solution to form the crude chlororhodic acid solution comprises:

adding a hydrochloric acid solution to the rhodium ash at a temperature of 60-80 ℃ to form a hydrochloric acid solution comprising rhodium ash;

under the stirring state, dropwise adding hydrogen peroxide solution into the hydrochloric acid solution containing rhodium ash to form a hydrochloric acid and hydrogen peroxide mixed solution containing rhodium ash;

and (3) reacting the mixed solution of hydrochloric acid containing rhodium ash and hydrogen peroxide at the temperature of 90-120 ℃ for 2-4h, and then cooling and filtering to obtain the crude chlororhodic acid solution.

In some embodiments, the hydrochloric acid solution is added in an amount of 15 to 18mL/g, preferably 16 to 17mL/g, based on the ratio of the volume of the hydrochloric acid solution to the mass of the rhodium ash; and/or

The adding amount of the hydrogen peroxide solution is 1.2-1.8, preferably 1.4-1.6 according to the volume ratio of the hydrogen peroxide solution to the hydrochloric acid solution; and/or

The concentration of the hydrochloric acid solution is 30-37 wt%, and the concentration of the hydrogen peroxide solution is 30-50 wt%.

In some embodiments, the content of rhodium ions in the crude chlororhodic acid solution is 2000-3000mg/L, preferably 2041-2987 mg/L.

Compared with the prior art, the invention has the following beneficial effects:

according to the method for recovering rhodium from waste rhodium catalyst residues, provided by the invention, after the waste rhodium catalyst residues are prepared into a crude chlororhodium acid solution, the crude chlororhodium acid solution is subjected to cold plasma glow discharge treatment, so that rhodium ions in the crude chlororhodium acid solution are reduced to form a rhodium simple substance. The method simplifies the treatment process of the waste rhodium catalyst residue after roasting in the traditional method for recovering rhodium, and has high recovery efficiency. In addition, the invention adopts a cold plasma glow discharge method to carry out reduction separation on rhodium ions in the crude chlororhodic acid solution, avoids introducing other organic solvents and reduces the recovery cost. In addition, the recovery rate of rhodium in the waste rhodium catalyst residue can reach more than 97 percent by adopting the method, and the purity of the recovered rhodium can reach more than 99 percent. Therefore, the method can be used for recovering the rhodium metal in an environment-friendly, efficient and economical manner, and has wide industrial application prospect.

Detailed Description

In order that the present invention may be more readily understood, the following detailed description of the invention is given by way of example only, and is not intended to limit the scope of the invention.

The current incineration method for recovering rhodium has the defects of large environmental pollution, high energy consumption, high requirements on equipment and production operation conditions and the like, and the wet method has the defects of long process flow, large quantity of organic reagents required, a plurality of limiting factors in the separation treatment process and the like, so that the large-scale application of the method in industry is limited. Repeated experimental research by the inventor of the invention finds that the cold plasma glow discharge technology is applied to the recovery treatment of rhodium, so that the treatment process after the waste rhodium catalyst residue is roasted in the traditional method for recovering rhodium can be simplified, other organic solvents are not required to be introduced for reducing rhodium ions, the recovery rate of rhodium is high, and the purity of the recovered rhodium is high. The present invention has been made based on the above findings.

Accordingly, the present invention provides a process for recovering rhodium from a spent rhodium catalyst residue comprising the steps of:

s1, roasting the waste rhodium catalyst residues to obtain rhodium ash;

s2, dissolving the rhodium ash in a hydrochloric acid and hydrogen peroxide solution to form a crude chlororhodic acid solution;

s3, subjecting the crude rhodium acid solution to cold plasma glow discharge treatment to obtain a rhodium metal film;

s4, the rhodium metal film is filtered, washed and dried to obtain the rhodium metal.

In step S1, the method of the baking treatment includes: firstly raising the temperature to a predetermined temperature T₁Is kept for a period of time t₁Then continuously raising the temperature to the roasting temperature T₂Is kept for a period of time t₂. Preferably, said predetermined temperature T₁At 400 ℃ and 500 ℃ t₁Is 2-3 h; the roasting temperature T₂At 600-800 deg.c, preferably at 700-750 deg.c; t is t₂Is 4-6 h. The roasting treatment is carried out in an oxygen atmosphere until no carbon oxide is released from tail gas. The organic matters in the waste rhodium catalyst residues can be fully removed through roasting treatment. And after the roasting treatment is finished, cooling the obtained product to room temperature to obtain rhodium ash.

The inventor of the present invention has found that if the roasting process of step S1 is directly heated to the roasting temperature, the effect is relatively poor; this is because the spent catalyst residue contains a large amount of organic substances such as phosphine, and the calcination process is an exothermic reaction, and the temperature rapidly rises over a period of time, so that rhodium is easily sublimated in the process, thereby causing rhodium loss. On the contrary, the adoption of the roasting process with the sectional heating can effectively reduce the loss of rhodium and simultaneously ensure that organic impurities are removed to the maximum extent.

Specifically, in step S2, the method of dissolving the rhodium ash in an aqueous solution of hydrochloric acid and hydrogen peroxide to form the crude chlororhodic acid solution includes the steps of:

s21, adding a hydrochloric acid solution into the rhodium ash at the temperature of 60-80 ℃ to form a hydrochloric acid solution containing the rhodium ash;

s22, dropwise adding hydrogen peroxide solution into the hydrochloric acid solution containing rhodium ash under stirring to form a mixed solution of hydrochloric acid containing rhodium ash and hydrogen peroxide;

s23, reacting the mixed solution of hydrochloric acid containing rhodium ash and hydrogen peroxide at the temperature of 90-120 ℃ for 2-4h, and then cooling and filtering to obtain the crude chlororhodic acid solution.

In step S21, the addition amount of the hydrochloric acid solution is 15-18mL/g, preferably 16-17mL/g, in terms of the ratio of the volume of the hydrochloric acid solution to the mass of the rhodium ash.

In step S22, the amount of the aqueous hydrogen peroxide solution added is 1.2 to 1.8, preferably 1.4 to 1.6, in terms of the volume ratio of the aqueous hydrogen peroxide solution to the hydrochloric acid solution.

The concentration of the hydrochloric acid solution adopted in the invention is 30-37 wt%, and the concentration of the hydrogen peroxide solution adopted is 30-50 wt%.

The dissolution treatment of step S2 was performed, so that rhodium ash was completely dissolved to form a crude chlororhodic acid solution. The content of rhodium ions in the crude chlororhodic acid solution is 2000-3000mg/L, preferably 2041-2987 mg/L.

Specifically, in step S3, the method for subjecting the crude rhodium acid solution to cold plasma glow discharge treatment comprises the following steps:

s31, placing a mixed solution formed by mixing the crude chlororhodic acid solution and a surfactant in a plasma discharge gas atmosphere;

and S32, under the action of alternating current, reducing rhodium ions in the mixed solution into a rhodium simple substance by plasma formed by the discharge of the plasma discharge gas.

In step S31, the ratio of the molar amount of rhodium ions in the crude chlororhodic acid solution to the mass of the surfactant is 1 (3.5-28.5) mol/g, preferably 1 (5-24) mol/g.

In the present invention, the surfactant includes polyvinylpyrrolidone and/or polyvinyl alcohol. The inventor of the invention researches and discovers that by adopting polyvinylpyrrolidone and/or polyvinyl alcohol as a surfactant, rhodium ions can be reduced into rhodium particles in the cold plasma glow discharge process, and then the rhodium particles can be better captured to form a metal film.

The plasma discharge gas in step S32 of the present invention is a gas plasma capable of generating positive and negative ions under high pressure. The plasma discharge gas comprises one or more of an inert gas, nitrogen and air, preferably an inert gas, more preferably argon. The inventors of the present invention have found that the selectivity and efficiency of the inert gas are higher compared to nitrogen and air because: (1) inert gases and other elements are difficult to form in a stable compound form; (2) inert gas, such as argon, has a high first ionization point, and the formed argon anions exist as electron-rich substances, so that high energy can be provided to act on rhodium ions to reduce the rhodium ions into nano metal rhodium, and finally the argon anions become argon.

In step S32, the voltage of the alternating current is 150-; the reduction time is 3-15 min. In the present invention, the discharge voltage (ac voltage) needs to be strictly controlled. Too low discharge voltage can result in weaker reduction reaction and lower rhodium yield; the discharge voltage is too high, so that the requirements on equipment, grounding environment and the like are high, the requirements are difficult to meet in practical application, and the product post-treatment process is difficult due to the too high voltage, the loss of rhodium is caused, and the yield of the noble metal rhodium is influenced.

After the treatment of step S3, the rhodium simple substance exists in the form of a rhodium metal film. Since the rhodium metal film is formed in the solution, it is necessary to centrifuge and filter the solid-liquid mixture, wash the resulting cake, and finally dry the cake to obtain the rhodium metal in the subsequent step S4.

The method for washing the filter cake comprises the following steps: washing with anhydrous methanol and acetonitrile in sequence until the filtrate is colorless, and then washing with deionized water until the filtrate is neutral in pH.

In order to further prepare rhodium metal into rhodium powder, the method for recovering rhodium from waste rhodium catalyst residues, provided by the invention, further comprises the following steps after the step S4:

s5, subjecting the rhodium metal to oxidation roasting treatment to form rhodium oxide;

and S6, reducing the rhodium oxide in a hydrogen atmosphere to obtain rhodium powder.

After step S4, the present invention can further remove some residual organic matters by using a roasting treatment, since part of rhodium is oxidized by the roasting treatment, a further reduction treatment is required after the roasting treatment, and the reduction treatment is also a process of removing impurities.

Preferably, in step S5, the temperature of the roasting treatment is 400-600 ℃, and the time of the roasting treatment is 1-3 h.

Preferably, in step S6, the temperature of the reduction treatment is 700-900 ℃, and the time of the reduction treatment is 4-6 h.

The starting materials used in the present invention are commercially available unless otherwise specified.

The operations and treatments involved in the present invention are conventional in the art unless otherwise specified.

The apparatus used in the present invention is an apparatus conventional in the art unless otherwise specified.

The test method or the calculation method provided by the invention is as follows:

the rhodium recovery is calculated as:

rhodium yield ═ rhodium powder mass g × rhodium powder purity ]/(% mass of rhodium in the crude chlororhodic acid solution:% mass of crude chlororhodic acid solution g) × 100%

The mass percentage of rhodium in the crude chlororhodic acid solution is analyzed by ICP (inductively coupled plasma emission spectrometer), and the purity of the rhodium powder is analyzed by ICP after the rhodium powder is electrified and dissolved by concentrated hydrochloric acid (37 wt%).

Examples

Example 1

20g of waste rhodium catalyst residue (the rhodium content is 3.45 wt%, determined by adopting a 37 wt% concentrated hydrochloric acid dissolving method) is weighed by using a 100mL evaporating dish, the evaporating dish is covered and a proper exhaust gap is left, the waste rhodium catalyst residue is placed in a muffle furnace, the temperature is raised to 400 ℃, the temperature is kept for 2 hours, then the temperature is raised to 600 ℃, the constant temperature roasting is carried out for 5 hours, and the waste rhodium catalyst residue is naturally cooled to the room temperature, so that 9.28g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 140mL of 37 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 15mL/g), stirring and heating to 60 ℃, slowly dropwise adding 167mL of 30 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.2), heating to 90 ℃ after dropwise adding, reacting for 3 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2041 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of rhodium ions, namely polyvinylpyrrolidone (by mass) 1:3.5mol/g, putting the mixed solution into a quartz boat, putting the quartz boat into a cold plasma discharger, putting the quartz boat between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling argon as discharge gas, applying 150V alternating voltage to the electrodes under normal pressure, reducing rhodium by cold plasma glow discharge for 5min, taking out a solid-liquid mixture after reaction, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, washing the solid-liquid mixture by anhydrous methanol and acetonitrile in sequence, washing the solid-liquid mixture until the pH is neutral by deionized water after washing, filtering the solid-liquid mixture, and drying the solid-liquid mixture to obtain the rhodium metal. And putting the obtained rhodium metal into a muffle furnace to react for 2h at 500 ℃ to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting at 700 ℃ for 6h in a hydrogen atmosphere to obtain 0.6735g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 97.66 percent, and the purity is 99.97 percent.

Example 2

20g of waste rhodium catalyst residue (the rhodium content is 3.45 wt%, determined by adopting a 37 wt% concentrated hydrochloric acid dissolving method) is weighed by using a 100mL evaporating dish, the evaporating dish is covered and a proper exhaust gap is left, the waste rhodium catalyst residue is placed in a muffle furnace, the temperature is raised to 450 ℃, the temperature is kept for 2 hours, then the temperature is raised to 800 ℃, the constant temperature roasting is carried out for 6 hours, and the waste rhodium catalyst residue is naturally cooled to the room temperature, so that 6.69g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 121mL of 30 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 18mL/g), stirring and heating to 80 ℃, slowly dropwise adding 217mL of 50 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.8), heating to 120 ℃ after dropwise adding, reacting for 4 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2967 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of crude chlororhodic acid (calculated by the molar weight of rhodium ions) and polyvinyl alcohol (mass) of 1:28.5mol/g, putting the mixed solution into a quartz boat, putting the quartz boat into a cold plasma discharger, putting the quartz boat between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling nitrogen as discharge gas, applying an alternating voltage of 500V on an electrode at normal pressure, reducing rhodium by cold plasma glow discharge for 3min, taking out a solid-liquid mixture after reaction, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, washing the solid-liquid mixture by anhydrous methanol and acetonitrile in sequence, washing the solid-liquid mixture until the pH is neutral by deionized water after washing, filtering, and drying the rhodium metal to obtain the rhodium metal. And putting the rhodium metal into a muffle furnace to react for 3 hours at 400 ℃ to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting for 4 hours at 900 ℃ in a hydrogen atmosphere to obtain 0.6714g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 97.33 percent, and the purity is 99.95 percent.

Example 3

20g of waste rhodium catalyst residue (the rhodium content is 3.45 wt%, determined by adopting a method of dissolving 37 wt% concentrated hydrochloric acid) is weighed by using a 100mL evaporating dish, the evaporating dish is covered and a proper exhaust gap is left, the waste rhodium catalyst residue is placed in a muffle furnace, the temperature is raised to 500 ℃, the temperature is kept for 3 hours, then the temperature is raised to 700 ℃, the constant temperature roasting is carried out for 4 hours, and the waste rhodium catalyst residue is naturally cooled to the room temperature, so that 7.51g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 128mL of 35 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 17mL/g), stirring and heating to 70 ℃, slowly dropwise adding 204mL of 40 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.6), heating to 100 ℃ after dropwise adding, reacting for 2 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2384 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of crude chlororhodic acid (calculated by rhodium ions) and polyvinylpyrrolidone solution of which the mass is 1:20mol/g, putting the mixed solution into a quartz boat, putting the quartz boat into a cold plasma discharger, putting the quartz boat between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling argon as discharge gas, applying an alternating voltage of 400V on an electrode at normal pressure, reducing rhodium by cold plasma glow discharge for 10min, taking out a solid-liquid mixture after reaction, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, sequentially washing the solid-liquid mixture by anhydrous methanol and acetonitrile until the solid-liquid mixture is colorless, washing the solid-liquid mixture by deionized water until the pH value is neutral, filtering the solid-liquid mixture, and drying the rhodium metal to obtain the rhodium metal. And putting the obtained rhodium metal into a muffle furnace to react for 1h at the temperature of 600 ℃ to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting for 5 hours at 800 ℃ in a hydrogen atmosphere to obtain 0.6708g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 97.24 percent, and the purity is 99.95 percent.

Example 4

20g of waste rhodium catalyst residues (the rhodium content is 3.45 wt%, determined by adopting a 37 wt% concentrated hydrochloric acid dissolving method) are weighed by using a 100mL evaporating dish, the evaporating dish is covered, a proper exhaust gap is reserved, the waste rhodium catalyst residues are placed in a muffle furnace, the temperature is raised to 480 ℃, the temperature is kept for 3 hours, then the temperature is raised to 750 ℃, the constant temperature roasting is carried out for 5 hours, and the waste rhodium catalyst residues are naturally cooled to room temperature, so that 7.38g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 118mL of 32 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 16mL/g), stirring and heating to 80 ℃, slowly dropwise adding 165mL of 50 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.4), heating to 120 ℃ after dropwise adding, reacting for 2 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2695 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of crude chlororhodic acid (calculated by the molar weight of rhodium ions) and polyvinyl alcohol (mass) of 1:15mol/g, putting the mixed solution into a quartz boat, putting the quartz boat into a cold plasma discharger, putting the quartz boat between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling air as discharge gas, applying 450V alternating voltage on an electrode at normal pressure, reducing rhodium by cold plasma glow discharge for 9min, taking out a solid-liquid mixture after the reaction is finished, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, washing the solid-liquid mixture by anhydrous methanol and acetonitrile in sequence, washing the solid-liquid mixture until the solid-liquid mixture is colorless, washing the solid-liquid mixture by deionized water until the pH value is neutral, filtering the solid-liquid mixture, and drying the rhodium metal to obtain. And putting the obtained rhodium metal into a muffle furnace to react for 1.5h at 550 ℃ to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting at 750 ℃ for 4 hours in a hydrogen atmosphere to obtain 0.6712g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 97.30%, and the purity is 99.95%.

Example 5

20g of waste rhodium catalyst residue (the rhodium content is 5.33 wt%, determined by a method of dissolving 37 wt% concentrated hydrochloric acid) is weighed by using a 100mL evaporating dish, the evaporating dish is covered and a proper exhaust gap is left, the waste rhodium catalyst residue is placed in a muffle furnace, the temperature is raised to 500 ℃, the temperature is kept for 3 hours, then the temperature is raised to 600 ℃, the waste rhodium catalyst residue is roasted for 4.5 hours at the constant temperature, and the waste rhodium catalyst residue is naturally cooled to the room temperature, so that 6.52g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 98mL of 36 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 15mL/g), stirring and heating to 60 ℃, slowly dropwise adding 118mL of 30 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.2), heating to 110 ℃ after dropwise adding, reacting for 3 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2049 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of crude chlororhodic acid (based on rhodium ions) and polyvinylpyrrolidone solution, putting the mixed solution into a quartz boat, putting the quartz boat and the quartz boat into a cold plasma discharger, putting the quartz boat and the mixed solution between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling argon as discharge gas, applying an alternating voltage of 200V to an electrode at normal pressure, reducing rhodium by cold plasma glow discharge for 3min, taking out a solid-liquid mixture after reaction, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, washing the solid-liquid mixture by anhydrous methanol and acetonitrile in sequence, washing the solid-liquid mixture until the solid-liquid mixture is colorless, washing the solid-liquid mixture by deionized water until the pH value is neutral, filtering the solid-liquid mixture, and drying the rhodium metal to obtain the rhodium metal. And putting the obtained rhodium metal into a muffle furnace to react for 2.5 hours at the temperature of 600 ℃ to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting for 5.5 hours at 800 ℃ in a hydrogen atmosphere to obtain 1.0352g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 97.13 percent, and the purity is 99.95 percent.

Example 6

20g of waste rhodium catalyst residue (the rhodium content is 5.33 wt%, determined by adopting a method of dissolving 37 wt% concentrated hydrochloric acid) is weighed by using a 100mL evaporating dish, the evaporating dish is covered and a proper exhaust gap is left, the waste rhodium catalyst residue is placed in a muffle furnace, the temperature is raised to 400 ℃, the temperature is kept for 3 hours, then the temperature is raised to 800 ℃, the constant temperature roasting is carried out for 4 hours, and the waste rhodium catalyst residue is naturally cooled to the room temperature, so that 5.12g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 93mL of 37 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 18mL/g), stirring and heating to 80 ℃, slowly dropwise adding 167mL of 50 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.8), heating to 100 ℃ after dropwise adding, reacting for 3 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2987 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of crude chlororhodic acid (calculated by the molar weight of rhodium ions) and polyvinyl alcohol (the mass ratio of polyvinyl alcohol) is 1:22.5mol/g, putting the mixed solution into a quartz boat, putting the quartz boat into a cold plasma discharger, putting the quartz boat between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling air as discharge gas, applying 250V alternating voltage on an electrode at normal pressure, reducing rhodium by cold plasma glow discharge for 14min, taking out a solid-liquid mixture after reaction, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, washing the solid-liquid mixture by anhydrous methanol and acetonitrile in sequence, washing the solid-liquid mixture until the solid-liquid mixture is colorless, washing the solid-liquid mixture by deionized water until the pH value is neutral, filtering the solid-liquid mixture, and drying the rhodium metal. And putting the obtained rhodium metal into a muffle furnace to react for 1.5h at 450 ℃ to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting for 4.5 hours at 850 ℃ in a hydrogen atmosphere to obtain 1.0357g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 97.17 percent, and the purity is 99.95 percent.

Example 7

20g of waste rhodium catalyst residue (the rhodium content is 5.33 wt%, determined by a method of dissolving 37 wt% concentrated hydrochloric acid) is weighed by using a 100mL evaporating dish, the evaporating dish is covered and a proper exhaust gap is left, the waste rhodium catalyst residue is placed in a muffle furnace, the temperature is raised to 450 ℃, the temperature is kept for 3 hours, then the temperature is raised to 700 ℃, the constant temperature roasting is carried out for 6 hours, and the waste rhodium catalyst residue is naturally cooled to the room temperature, so that 5.32g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 91mL of 31 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 17mL/g), stirring and heating to 70 ℃, slowly dropwise adding 145mL of 40 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.6), heating to 90 ℃ after dropwise adding, reacting for 4 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2541 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of rhodium ions, namely polyvinylpyrrolidone (by mass) 1:15.5mol/g, putting the mixed solution into a quartz boat, putting the quartz boat into a cold plasma discharger, putting the quartz boat between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling air as discharge gas, applying 300V alternating voltage on an electrode at normal pressure, reducing rhodium by cold plasma glow discharge for 12min, taking out a solid-liquid mixture after reaction, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, washing the solid-liquid mixture by anhydrous methanol and acetonitrile in sequence, washing the solid-liquid mixture until the pH is neutral by deionized water after washing, filtering the solid-liquid mixture, and drying the solid-liquid mixture to obtain the rhodium metal. And putting the obtained rhodium metal into a muffle furnace to react for 2.5 hours at the temperature of 600 ℃ to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting for 5 hours at 900 ℃ in a hydrogen atmosphere to obtain 1.0349g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 97.10 percent, and the purity is 99.95 percent.

Example 8

20g of waste rhodium catalyst residue (the rhodium content is 5.33 wt%, determined by a method of dissolving 37 wt% concentrated hydrochloric acid) is weighed by using a 100mL evaporating dish, the evaporating dish is covered and a proper exhaust gap is left, the waste rhodium catalyst residue is placed in a muffle furnace, the temperature is raised to 450 ℃, the temperature is kept for 3 hours, then the temperature is raised to 750 ℃, the temperature is kept for roasting for 5 hours, and the waste rhodium catalyst residue is naturally cooled to room temperature, so that 4.94g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 80mL of 35 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 16mL/g), stirring and heating to 80 ℃, slowly dropwise adding 119mL of 50 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.5), heating to 110 ℃ after dropwise adding, reacting for 3 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2926 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of crude chlororhodic acid (calculated by rhodium ions) and polyvinylpyrrolidone solution, putting the mixed solution into a quartz boat and a cold plasma discharger, putting the quartz boat and the mixed solution between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling argon as discharge gas, applying an alternating voltage of 500V to an electrode at normal pressure, reducing rhodium by cold plasma glow discharge for 7min, taking out a solid-liquid mixture after reaction, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, washing the solid-liquid mixture by anhydrous methanol and acetonitrile in sequence, washing the solid-liquid mixture until the solid-liquid mixture is colorless, washing the solid-liquid mixture by deionized water until the pH value is neutral, filtering the solid-liquid mixture, and drying the rhodium metal to obtain the rhodium metal. And putting the obtained rhodium metal into a muffle furnace for reaction at 550 ℃ for 3h to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting at 750 ℃ for 6h in a hydrogen atmosphere to obtain 1.0347g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 97.08%, and the purity is 99.95%.

Example 9

20g of waste rhodium catalyst residue (the rhodium content is 5.33 wt%, determined by a method of dissolving 37 wt% concentrated hydrochloric acid) is weighed by using a 100mL evaporating dish, the evaporating dish is covered and a proper exhaust gap is left, the waste rhodium catalyst residue is placed in a muffle furnace, the temperature is raised to 450 ℃, the temperature is kept for 3 hours, then the temperature is raised to 750 ℃, the temperature is kept for roasting for 5 hours, and the waste rhodium catalyst residue is naturally cooled to room temperature, so that 4.88g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 78mL of 35 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 16mL/g), stirring and heating to 80 ℃, slowly dropwise adding 117mL of 50 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.5), heating to 110 ℃ after dropwise adding, reacting for 3 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2872 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of crude chlororhodic acid (calculated by rhodium ions) and polyvinylpyrrolidone solution, putting the mixed solution into a quartz boat, putting the quartz boat and the quartz boat into a cold plasma discharger, putting the quartz boat and the mixed solution between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling argon as discharge gas, applying 550V alternating voltage to an electrode at normal pressure, reducing rhodium by cold plasma glow discharge for 7min, taking out a solid-liquid mixture after reaction, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, washing the solid-liquid mixture by anhydrous methanol and acetonitrile in sequence, washing the solid-liquid mixture until the solid-liquid mixture is colorless, washing the solid-liquid mixture by deionized water until the pH value is neutral, filtering the solid-liquid mixture, and drying the rhodium metal to obtain the rhodium metal. And putting the obtained rhodium metal into a muffle furnace for reaction at 550 ℃ for 3h to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting at 750 ℃ for 6h in a hydrogen atmosphere to obtain 1.0129g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 95.03%, and the purity is 99.89%.

Example 10

20g of waste rhodium catalyst residue (the rhodium content is 5.33 wt%, determined by a method of dissolving 37 wt% concentrated hydrochloric acid) is weighed by using a 100mL evaporating dish, the evaporating dish is covered and a proper exhaust gap is left, the waste rhodium catalyst residue is placed in a muffle furnace, the temperature is raised to 350 ℃, the temperature is kept for 3 hours, then the temperature is raised to 550 ℃, the waste rhodium catalyst residue is roasted for 6 hours at the constant temperature, and the waste rhodium catalyst residue is naturally cooled to room temperature, so that 8.35g of rhodium ash is obtained. Adding rhodium ash into a 1000mL three-neck flask, adding 142mL of 31 wt% hydrochloric acid (the volume mass ratio of the hydrochloric acid to the rhodium ash is 17mL/g), stirring and heating to 70 ℃, slowly dropwise adding 227mL of 40 wt% hydrogen peroxide (the volume ratio of the hydrogen peroxide to the hydrochloric acid is 1.6), heating to 90 ℃ after dropwise adding, reacting for 4 hours, stirring and cooling to room temperature, filtering, washing filter residues with deionized water, and collecting filtrate. The operation was repeated three times and the filtrate was collected. And analyzing and detecting the collected filtrate, and concentrating to obtain a crude chlororhodic acid solution with the rhodium content of 2351 mg/L. Uniformly mixing a crude chlororhodic acid solution and a polyvinylpyrrolidone solution according to the molar weight of rhodium ions, namely polyvinylpyrrolidone (by mass) 1:15.5mol/g, putting the mixed solution into a quartz boat, putting the quartz boat into a cold plasma discharger, putting the quartz boat between two electrode plates of a discharge tube in a vacuum chamber, sealing the vacuum chamber, vacuumizing the vacuum chamber, filling argon as discharge gas, applying 300V alternating voltage to the electrodes under normal pressure, reducing rhodium by cold plasma glow discharge for 12min, taking out a solid-liquid mixture after reaction, centrifuging the solid-liquid mixture, filtering the solid-liquid mixture, washing the solid-liquid mixture by anhydrous methanol and acetonitrile in sequence, washing the solid-liquid mixture until the pH is neutral by deionized water after washing, filtering the solid-liquid mixture, and drying the solid-liquid mixture to obtain the rhodium metal. And putting the obtained rhodium metal into a muffle furnace to react for 2.5 hours at the temperature of 600 ℃ to obtain rhodium oxide. And putting the rhodium oxide into a hydrogen reduction furnace, and reacting for 5 hours at 900 ℃ in a hydrogen atmosphere to obtain 0.9915g of high-purity rhodium powder, wherein the recovery rate of the rhodium is 93.03 percent, and the purity is 99.91 percent.

From the above examples, it can be seen that the recovery rate of rhodium in the method for recovering rhodium from waste rhodium catalyst residues provided by the invention can reach more than 97%, and the purity of the recovered rhodium can reach more than 99%, so that better effects are obtained. Therefore, the invention provides a method for efficiently and environmentally recovering rhodium, and the method has wide industrial application prospect.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.