A method for enriching and recovering rhodium from low-rhodium, high-impurity waste liquid

Abstract

This invention discloses a method for enriching and recovering rhodium from low-rhodium, high-impurity waste liquid. The specific process steps are as follows: Precipitant A is dissolved in hydrochloric acid to obtain precipitate solution A; additive A is added to the low-rhodium, high-impurity waste liquid, followed by the addition of precipitate solution A to precipitate rhodium, resulting in rhodium precipitate; after oxidizing and dissolving the rhodium precipitate, it is first evaporated and concentrated, then rapidly cooled with ice to precipitate lead; after lead precipitation, precipitant B is added to the filtrate to remove palladium; after palladium removal, the filtrate is first concentrated, then neutralized and hydrolyzed to obtain a hydrolyzed rhodium precipitate; the hydrolyzed precipitate is dissolved in hydrochloric acid and reduced with reducing agent A to obtain rhodium slag; the rhodium slag is washed and then calcined in a muffle furnace, boiled in aqua regia, and reduced with hydrogen to obtain pure rhodium powder. This invention has the advantages of being able to treat low-rhodium, high-impurity waste liquid, having a wide range of applicable materials, and being easy to industrialize.

Description

Technical Field

[0001] This invention belongs to the field of rhodium recovery, and specifically relates to a method for enriching and recovering rhodium from low-rhodium, high-impurity waste liquid. Background Technology

[0002] Rhodium, a precious metal, is widely used in manufacturing industries such as chemical engineering, aerospace, and electronics. Although the amount used is small, it plays a crucial role and is known as the "vitamin of industry." However, rhodium resources are limited and expensive, and the price of rhodium on the international market is rising. Therefore, the efficient recovery of rhodium from secondary resources is of great significance for the sustainable use of national resources.

[0003] Currently, the recovery of secondary rhodium resources mainly focuses on rhodium-containing spent catalysts, rhodium-related product production, and rhodium-containing waste liquids generated during rare and precious metal production processes. Extensive research and methods have been developed for the recovery of rhodium from spent catalysts, while the main methods for recovering rhodium from rhodium-containing waste liquids include incineration and wet processes.

[0004] The incineration method involves sending rhodium-containing waste liquid to an incinerator to burn off volatile elements, obtaining rhodium-containing salt residue, and then performing wet purification to obtain a high-concentration rhodium solution or rhodium residue.

[0005] The method disclosed in patent CN102247841 is as follows: Rhodium-containing waste liquid is sent to an incinerator for incineration, and the incinerated material is then sent to an ashing furnace for ashing. The ashing material is then mixed with a mixture of sodium peroxide and sodium hydroxide and melted and oxidized at a temperature of 800-900°C to transform into rhodium oxide. An appropriate amount of industrial hydrochloric acid is added to the rhodium oxide, and a 10% NaClO3 aqueous solution is slowly added dropwise at a temperature of 80-90°C to convert the rhodium oxide into a rhodium salt aqueous solution. The rhodium salt aqueous solution is then replaced with zinc powder to obtain recovered rhodium powder.

[0006] The method for recovering rhodium from rhodium-containing waste liquid disclosed in German Patent 2438847 is as follows: the rhodium-containing waste liquid is sent into a submerged combustion chamber along with air and incinerated at 1150°C for 20 hours. The submerged combustion chamber is filled with water, and the gas produced after combustion is absorbed by the water in the submerged combustion chamber. The rhodium remains in a suspended state in the water in the submerged combustion chamber, and rhodium powder is obtained by filtration.

[0007] The method for recovering rhodium from rhodium-containing waste liquid disclosed in patent CN1176232 is as follows: using alkali metal or alkaline earth metal carbonates as additives, the rhodium-containing waste liquid is incinerated and ashed at 650-700℃, and the remaining residue is reacted with molten alkali metal acid sulfates to generate soluble rhodium salts, and then the rhodium is separated by electrolysis.

[0008] The method disclosed in Chinese Patent CN 111020200 is as follows: Rhodium-containing waste liquid is concentrated and distilled to remove light components, which are then mixed with sawdust. The concentrated rhodium-containing waste liquid is then initially incinerated to produce rhodium-containing charcoal slag, which is then acid-washed and water-washed. The rhodium-containing charcoal slag is then incinerated a second time to produce rhodium-containing ash slag, which is then acid-washed, water-washed, alkali-washed, and water-washed. Finally, the dust and incineration residue from the incineration process are combined and reacted with alkali metal acid sulfates to generate soluble rhodium salts. The soluble rhodium salts react with active metals to obtain rhodium.

[0009] However, the above incineration methods for treating rhodium-containing waste liquid all have a drawback: the loss of rhodium during the incineration process is too great, and the energy consumption is high.

[0010] Wet processes typically include physical and chemical methods, such as precipitation separation, ion exchange, electrodeposition, adsorption, and reduction. Precipitation separation and ion exchange are the most widely used. Precipitation separation is technically mature, simple, and easy to operate; however, its application is limited for rhodium ions, and the conditions are relatively strict, making it difficult to use. Ion exchange achieves separation and recovery based on ion exchange and is widely used in metal recovery. It also has advantages such as simple operation and large throughput. However, for precious metal recovery, the resin is expensive, the regeneration requires large dosages, it easily generates new waste liquid, pollutes the environment, and the resin's operating range is relatively narrow, with high requirements for operating conditions.

[0011] The method disclosed in CN112442594 involves treating rhodium-containing wastewater with cold plasma glow discharge to reduce rhodium ions in the wastewater to elemental rhodium. While this method offers advantages such as high selectivity and high separation efficiency, it is difficult to industrialize.

[0012] The method disclosed in CN114134335 is as follows: first, other precious metal impurities are removed by water treatment agent and acidic reducing agent, then the pH is adjusted to >7, and sodium borohydride is added to reduce rhodium to rhodium black.

[0013] The method disclosed in CN101275184 is to recover rhodium by reducing ammonium hexachlororhodium solution with formic acid.

[0014] The method disclosed in CN112111659 is to recover rhodium by reducing it with nitrite and hydrazine hydrate.

[0015] The method disclosed in CN103498056 is to recover rhodium by displacement reduction with active metals, but this method requires a large amount of active metals, resulting in high production costs, which is not conducive to industrial production.

[0016] The method disclosed in CN115558793 involves adding ethylenediamine to a platinum-palladium-rhodium solution to precipitate rhodium, followed by calcination and hydrogen reduction to obtain rhodium powder. This method is only suitable for automotive waste catalyst solutions containing only platinum, palladium, and rhodium, and is not suitable for industrial waste liquids with high impurities.

[0017] The above-mentioned wet process methods for rhodium recovery all have certain requirements on the rhodium concentration and impurity content of the rhodium-containing waste liquid. They are not effective in recovering rhodium from low-rhodium, high-impurity industrial waste liquids. Currently, there is no effective method for rhodium recovery from low-rhodium, high-impurity waste liquids. Summary of the Invention

[0018] This invention discloses a method for enriching and recovering rhodium from low-rhodium, high-impurity waste liquid to solve any of the above-mentioned and other potential problems of the prior art.

[0019] To achieve the above objectives, the technical solution of the present invention is: a method for enriching and recovering rhodium from low-rhodium, high-impurity waste liquid, the method comprising the following process steps:

[0020] S1) Prepare a solution to precipitate A;

[0021] S2) After heating the low-rhodium, high-impurity waste liquid to a certain temperature, add additive A, and then slowly add the precipitate solution A obtained in S1). After reacting for a period of time, cool and filter and wash to obtain rhodium precipitate.

[0022] S3) After mixing the rhodium precipitate obtained in S2) with dilute sulfuric acid, heat it to a certain temperature, and then gradually add the mixed solution until the rhodium precipitate is completely dissolved to obtain a solution;

[0023] S4) Evaporate and concentrate the solution obtained in S3). When crystals precipitate in the solution system, add ice to rapidly cool to the final temperature. After standing, filter to obtain filtrate A.

[0024] S5) Add precipitant B to the filtrate obtained in S4) to remove palladium, react for a period of time, and then filter to obtain filtrate B;

[0025] S6) Evaporate and concentrate the filtrate B obtained in S5) until the solution system becomes viscous. Then slowly add NaOH solution to adjust the pH value and add additive C. Then continue to add NaOH solution to adjust the pH value. After reacting for a period of time, filter after standing. Wash the hydrolyzed precipitate with deionized water multiple times.

[0026] S7) Dissolve the hydrolyzed precipitate after washing in S6) in dilute hydrochloric acid. After the hydrolyzed precipitate is completely dissolved, add reducing agent A. After reacting for a period of time, let it stand and filter to obtain rhodium slag. Wash the rhodium slag with deionized water several times.

[0027] S8) The rhodium slag obtained in S7) is calcined to obtain rhodium black. The rhodium black is then boiled and washed with aqua regia, cooled and filtered. The filter residue is washed multiple times with deionized water, dried, and then reduced by hydrogen gas to obtain pure rhodium powder.

[0028] Furthermore, the specific steps of S1) are as follows:

[0029] Precipitant A is mixed with hydrochloric acid with a concentration of 2-3 mol / L to prepare precipitant solution A with a concentration of 80-90 g / L;

[0030] The precipitant A is one or more of tetramethylethylenediamine hydrochloride, diaminoethane hydrochloride, or dimethylamine hydrochloride.

[0031] Furthermore, the low-rhodium, high-impurity waste liquid mentioned in S2) is the tailings liquid generated after extracting platinum and palladium in industrial production;

[0032] The amount of additive A added is such that the mass ratio of additive A to the rhodium content in the low-rhodium, high-impurity waste liquid is 1:1.

[0033] Additive A is one or more of hydrogen peroxide, sodium chlorate, and sodium hypochlorite.

[0034] Furthermore, the dissolution method of the rhodium precipitate in S3) is as follows: first, add the rhodium precipitate and dilute sulfuric acid with a concentration of 1 mol / L to the reaction vessel, heat to 60-80℃, and then add the mixed solution. The mass ratio of the mixed solution added is: mixed solution: rhodium = 2-3:1.

[0035] The mixed solution has a mass ratio of sodium chlorate to sodium chloride of 1:4.

[0036] Furthermore, the final temperature in S4) is 5-10℃, and the settling time is 22-26h.

[0037] Furthermore, the amount of precipitant B added in S5) is: precipitant B: palladium = 2~3:1;

[0038] The precipitant B is diacetyldioxime.

[0039] Furthermore, the evaporation and concentration process in S6) is as follows: after concentrating the solution system to a viscous state, NaOH solution is slowly added to adjust the pH. When the pH is adjusted to 6-7, additive C is added, and then NaOH solution is added to adjust the pH to 9-10. The reaction is carried out for 4-6 hours, and after standing for 12-15 hours, it is filtered. The hydrolyzed precipitate is washed with deionized water 4-6 times to neutralize it. Evaporation and concentration are required before hydrolysis. The concentration endpoint is when the solution becomes viscous.

[0040] Furthermore, the addition point of additive C is when the solution pH is 6-7, and the mass ratio of additive C added is: precipitant C: rhodium = 2-3:1; the additive C is sodium hypochlorite.

[0041] Furthermore, the amount added in S7) is in the following mass ratio: reducing agent A: rhodium = 5-6: the reducing agent A is sodium EVC.

[0042] Furthermore, the specific process of S8) is as follows: calcining at 600-700℃ for 4-6 hours to obtain rhodium black, boiling and washing the rhodium black with aqua regia for 20-30 minutes, cooling and filtering, washing the filter residue with deionized water 2-3 times, drying and placing it in a tube furnace, and reducing it with hydrogen at 600-800℃ for 4-6 hours.

[0043] Compared with traditional pyrometallurgical and hydrometallurgical processes for rhodium extraction, the technical solution of this invention has the following advantages:

[0044] (1) It has strong applicability to raw materials and has significant advantages in the field of rhodium extraction from low-rhodium and high-impurity waste liquid in industry. It can directly extract rhodium powder that meets national standards.

[0045] (2) High recovery rate: By precisely controlling various parameters in the rhodium extraction process, the rhodium recovery rate can reach over 90%.

[0046] (3) The process is simple. This patent uses wet refining and purification and pyrometallurgical reduction to prepare rhodium powder. There are no complicated procedures, it is easy to industrialize, and it has promotion and application value. Attached Figure Description

[0047] Figure 1 The present invention provides a process flow diagram for enriching and recovering rhodium from low-rhodium, high-impurity waste liquid. Detailed Implementation

[0048] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0049] like Figure 1 As shown, this invention provides a method for enriching and recovering rhodium from low-rhodium, high-impurity waste liquid. This method fills a gap in the field of industrial recovery technology for low-rhodium, high-impurity waste liquid, and provides a method for recovering rhodium from such waste liquid. The precipitant selected in this invention has good selectivity, is simple to operate, and is easy to implement in industrial production.

[0050] Specifically, the following steps are included:

[0051] S1. Pour precipitant A into a beaker and add hydrochloric acid with a concentration of 2-3 mol / L to dissolve it, thus preparing a precipitant solution A with a concentration of 80-90 g / L.

[0052] S2, add the low-rhodium, high-impurity waste liquid into the reactor, start stirring, heat to 50-70℃ and add additive A, then slowly add the precipitate solution A from step S1, react for 6-8 hours, cool and filter and wash to obtain rhodium precipitate.

[0053] S3, add the rhodium precipitate from S2 and dilute sulfuric acid with a concentration of 1 mol / L to the reaction vessel, start stirring, heat to 70-80℃, and then gradually add a mixed solution of sodium chlorate and sodium chloride in a ratio of 1:4 until the rhodium precipitate is completely dissolved;

[0054] S4. Add the solution from S3 to the evaporator for evaporation and concentration. When crystals precipitate in the solution system, add ice to cool it rapidly to 5-10℃. Let it stand for 24 hours and then filter.

[0055] S5. Add the filtrate from S4 to the reaction vessel, start stirring, then add precipitant B to remove palladium, react for 1-2 hours and then filter.

[0056] S6. Add the filtrate from S5 to the evaporator for evaporation and concentration. After the solution becomes viscous, slowly add NaOH solution to adjust the pH. When the pH is adjusted to 6-7, add additive C. Then continue to add NaOH solution to adjust the pH to 9-10. React for 4-6 hours, let stand for 12-15 hours, filter, and wash the hydrolyzed precipitate with deionized water 4-6 times.

[0057] S7. Add the hydrolysis precipitate from S6 to the reaction vessel, then add dilute hydrochloric acid with a concentration of 2-3 mol / L to dissolve it. After the hydrolysis precipitate has completely dissolved, add reducing agent A and react for 6-8 hours. After standing for 12 hours, filter to obtain rhodium slag. Wash the rhodium slag with deionized water 2-3 times.

[0058] S8. The rhodium slag from S7 is placed in a muffle furnace and calcined at 600-700℃ for 4-6 hours to obtain rhodium black. The rhodium black is boiled and washed with aqua regia for 20-30 minutes, cooled and filtered. The filter residue is washed with deionized water 2-3 times, dried and placed in a tube furnace for hydrogen reduction at 600-800℃ for 4-6 hours to obtain pure rhodium powder.

[0059] Precipitant A in S1 is tetramethylethylenediamine hydrochloride (C6H4O2). 18 ClN), diaminoethane hydrochloride (C2H) 10 One or more of the following hydrochloric acid complex organic salts (R-NHCl) such as Cl2N2 and dimethylamine hydrochloride (C2H8ClN), and R-NH formed after R-NHCl dissolves in an acidic solution. + Ion-pair with rhodium hexachlororhodium ion ([RhCl6)) 3-It exhibits strong selectivity, forming [R-NH]3[RhCl6] precipitate, thereby achieving the purpose of enriching rhodium in waste liquid. The chemical reaction formulas for the chemical reactions occurring in this step are as follows: (mechanism, applications)

[0060] R-NHCl+H3RhCl6→[R-NH]3[RhCl6]↓+HCl

[0061] The low-rhodium, high-impurity waste liquid mentioned in S2 is the tailings produced after extracting platinum and palladium in industrial production.

[0062] Additive A mentioned in S2 is one or more of strong oxidizing compounds such as hydrogen peroxide (H2O2), sodium chlorate (NaClO3), and sodium hypochlorite (NaClO). The formula for calculating the amount of strong oxidizing agent added is as follows:

[0063] m = (m1 × M) / (18 × n)

[0064] Where m represents the mass of the strong oxidizing agent to be calculated, m1 represents the mass of rhodium in the solution, M represents the relative atomic mass of the strong oxidizing agent to be calculated, and n represents the number of electrons gained or lost per unit of the strong oxidizing agent to be calculated.

[0065] In S2, the amount of precipitant A added, by mass ratio, is: precipitant A: rhodium = 4~5:1.

[0066] The method for dissolving the rhodium precipitate in S3 is as follows: First, add the rhodium precipitate and dilute sulfuric acid with a concentration of 1 mol / L to the reaction vessel, heat to 70-80℃, and then add a mixed solution of sodium chlorate and sodium chloride in a ratio of 1:4. The mass ratio of sodium chlorate added is 2-3:1.

[0067] The precipitant B in S5 is diacetyl dioxime (C4H8N2O2), and the mass ratio of precipitant B added is: precipitant B: palladium = 2~3:1.

[0068] S6 needs to be evaporated and concentrated before neutralization and hydrolysis. The concentration endpoint is when the solution becomes viscous.

[0069] Additive C in S6 is sodium hypochlorite (NaClO). The addition point is when the solution pH is 6-7. The mass ratio of additive C to precipitant C to rhodium is 2-3:1.

[0070] The neutralization and hydrolysis endpoint in S6 is pH = 9-10.

[0071] The reducing agent A mentioned in S7 is sodium EVC (C6H8O6), and the amount of sodium EVC added is: sodium EVC: rhodium = 5~6:1 by mass ratio.

[0072] Example 1:

[0073] The main components of the rhodium-containing waste liquid (g / L) are: Rh 0.15, Ir 0.081, Ru 0.39, Pt 0.25, Pd 1.67, Au 0.001, Ag 0.002, Se 0.25, Te 2.43, Pb 1.69, HCl 92. First, dissolve diaminoethane hydrochloride in 3 mol / L hydrochloric acid to prepare a precipitate solution A with a concentration of 90 g / L. Then, add 150 L of the above-mentioned low-rhodium, high-impurity waste liquid to a reaction vessel, heat to 60°C, add 20 g of sodium chlorate first, then add precipitate solution A, react for 6 hours, and filter to obtain rhodium precipitate. Add 1 mol / L dilute sulfuric acid to the rhodium precipitate, heat to 70°C, and then slowly add a mixed solution of sodium chlorate:sodium chloride = 1:4 to dissolve it. Add the solution to an evaporator for concentration, and when crystals precipitate in the solution, add ice to rapidly cool to -6°C, let stand for 24 hours, and then filter. Add 25 g of diacetyl dioxime to the filtrate to remove palladium, react for 2 hours, and then filter. Add the filtrate to an evaporator for concentration, and when the solution becomes viscous, slowly add a solution with a concentration of... A 40 g / L NaOH solution was prepared, and when the pH reached 7, 50 g of sodium hypochlorite was added. NaOH solution was then added to adjust the pH to 9. The reaction was allowed to proceed for 6 hours, followed by 15 hours of standing. The mixture was then filtered to obtain a hydrolyzed precipitate, which was washed four times with deionized water. The precipitate was then dissolved in 3 L of 2 mol / L dilute hydrochloric acid, and 90 g of sodium EVC was added. The reaction proceeded for 8 hours, followed by 12 hours of standing. The precipitate was then filtered, and the residue was washed twice with deionized water. The precipitate was then placed in a muffle furnace and calcined at 700°C for 6 hours to obtain rhodium black. The rhodium black was boiled and washed in 400 ml of aqua regia for 30 minutes, cooled, and then filtered. The residue was washed three times with deionized water, dried, and then placed in a tube furnace for hydrogen reduction at 800°C for 6 hours to obtain pure rhodium powder with a purity of 99.991%.

[0074] Example 2:

[0075] The main components of the rhodium-containing waste liquid (g / L) are: Rh 0.13, Ir 0.061, Ru 0.42, Pt 0.26, Pd 1.27, Au 0.001, Ag 0.001, Se 0.27, Te 2.23, Pb 1.88, HCl 98. First, dissolve diaminoethane hydrochloride in 2 mol / L hydrochloric acid to prepare a precipitate solution A with a concentration of 80 g / L. Then, add 150 L of the above-mentioned low-rhodium, high-impurity waste liquid to a reaction vessel, heat to 60°C, add 25 g of sodium chlorate first, then add precipitate solution A, react for 6 hours, and filter to obtain rhodium precipitate. Add 1 mol / L dilute sulfuric acid to the rhodium precipitate, heat to 80°C, and then slowly add a mixed solution of sodium chlorate:sodium chloride = 1:4 to dissolve it. Add the solution to an evaporator for concentration, and when crystals precipitate in the solution, add ice to rapidly cool to 8°C, let stand for 24 hours, and then filter. Add 28 g of diacetyl dioxime to the filtrate to remove palladium, react for 1 hour, and then filter. Add the filtrate to an evaporator for concentration, and when the solution becomes viscous, slowly add a 4% concentration of diacetyl dioxime. 0 g / L NaOH solution was used. When the pH of the solution reached 6, 45 g of sodium hypochlorite was added. Then, NaOH solution was added to adjust the pH to 10. The reaction was allowed to proceed for 5 hours. After standing for 15 hours, the solution was filtered to obtain a hydrolyzed precipitate, which was washed 5 times with deionized water. The precipitate was then dissolved in 3 L of 2 mol / L dilute hydrochloric acid. After dissolution, 90 g of sodium EVC was added and the reaction was allowed to proceed for 7 hours. After standing for 12 hours, the solution was filtered, and the residue was washed twice with deionized water. The solution was then placed in a muffle furnace and calcined at 600 °C for 6 hours to obtain rhodium black. The rhodium black was boiled and washed with 400 ml of aqua regia for 30 minutes. After cooling, the solution was filtered, and the residue was washed 3 times with deionized water. After drying, the solution was placed in a tube furnace and reduced with hydrogen at 700 °C for 6 hours to obtain pure rhodium powder with a purity of 99.995%.

[0076] Example 3:

[0077] The main components of the rhodium-containing waste liquid (g / L) are: Rh 0.17, Ir 0.028, Ru 0.16, Pt 0.31, Pd 1.87, Au 0.002, Ag 0.001, Se 0.32, Te 2.51, Pb 1.49, HCl 91. First, tetramethylethylenediamine hydrochloride was dissolved in 3 mol / L hydrochloric acid to prepare a precipitate solution A with a concentration of 85 g / L. Then, 150 L of the above-mentioned low-rhodium, high-impurity waste liquid was added to a reaction vessel, and the temperature was raised to 70°C. 30 g of sodium chlorate was added first, followed by precipitate solution A. After reacting for 8 hours, the solution was filtered to obtain rhodium precipitate. The rhodium precipitate was added to 1 mol / L dilute sulfuric acid, and the temperature was raised to 75°C. Then, a mixed solution of sodium chlorate and sodium chloride (1:4) was slowly added to dissolve it. The solution was added to an evaporator for concentration. When crystals precipitated in the solution, ice was added to rapidly cool the solution to 10°C. After standing for 24 hours, the solution was filtered. 30 g of diacetyl dioxime was added to the filtrate to remove palladium. After reacting for 1 hour, the solution was filtered. The filtrate was added to an evaporator for concentration. After the solution became viscous, a concentrated solution was slowly added to the evaporator for concentration. A 40 g / L NaOH solution was prepared. When the pH of the solution reached 7, 45 g of sodium hypochlorite was added, and then NaOH solution was added to adjust the pH to 9. The reaction was allowed to proceed for 6 hours, and after standing for 15 hours, the solution was filtered to obtain a hydrolyzed precipitate. The hydrolyzed precipitate was washed 6 times with deionized water. Then, it was dissolved in 3 L of 3 mol / L dilute hydrochloric acid. After dissolution, 90 g of sodium EVC was added and reacted for 7 hours. After standing for 12 hours, the solution was filtered, and the filter residue was washed 3 times with deionized water. Then, it was placed in a muffle furnace and calcined at 650 °C for 6 hours to obtain rhodium black. The rhodium black was boiled and washed with 400 ml of aqua regia for 25 minutes. After cooling, it was filtered, and the filter residue was washed 3 times with deionized water. After drying, it was placed in a tube furnace and reduced with hydrogen at 800 °C for 4 hours to obtain pure rhodium powder with a purity of 99.992%.

[0078] Example 4:

[0079] The main components of the rhodium-containing waste liquid (g / L) are: Rh 0.19, Ir 0.067, Ru 0.35, Pt 0.19, Pd 1.88, Au 0.001, Ag 0.001, Se 0.27, Te 2.48, Pb 1.33, HCl 103. First, tetramethylethylenediamine hydrochloride was dissolved in 2.5 mol / L hydrochloric acid to prepare a precipitate solution A with a concentration of 85 g / L. Then, 150 L of the above-mentioned low-rhodium, high-impurity waste liquid was added to a reaction vessel, and the temperature was raised to 60°C. 25 g of sodium chlorate was added first, followed by precipitate solution A. After reacting for 7 hours, the solution was filtered to obtain rhodium precipitate. The rhodium precipitate was added to 1 mol / L dilute sulfuric acid, and the temperature was raised to 80°C. Then, a mixed solution of sodium chlorate and sodium chloride (1:4) was slowly added to dissolve it. The solution was concentrated in an evaporator. When crystals precipitated in the solution, ice was added to rapidly cool the solution to 8°C. After standing for 24 hours, the solution was filtered. 30 g of diacetyl dioxime was added to the filtrate to remove palladium. After reacting for 2 hours, the solution was filtered. The filtrate was concentrated in an evaporator. When the solution became viscous, a solution of [missing information - likely a specific concentration] was slowly added to the evaporator. A 40 g / L NaOH solution was prepared, and when the pH reached 6, 55 g of sodium hypochlorite was added. NaOH solution was then added to adjust the pH to 10. The reaction was allowed to proceed for 5 hours, followed by standing for 13 hours. The mixture was then filtered to obtain a hydrolyzed precipitate, which was washed five times with deionized water. The precipitate was then dissolved in 3 L of 2.5 mol / L dilute hydrochloric acid, and 90 g of sodium EVC was added. The reaction proceeded for 7 hours, followed by standing for 12 hours. The precipitate was then filtered, and the residue was washed twice with deionized water. The precipitate was then placed in a muffle furnace and calcined at 700 °C for 6 hours to obtain rhodium black. The rhodium black was boiled and washed with 400 ml of aqua regia for 25 minutes, cooled, and then filtered. The residue was washed three times with deionized water, dried, and then placed in a tube furnace for hydrogen reduction at 700 °C for 5 hours to obtain pure rhodium powder with a purity of 99.993%.

[0080] Example 5:

[0081] The main components of the rhodium-containing waste liquid are (g / L): Rh 0.15, Ir 0.071, Ru 0.46, Pt 0.23, Pd 1.65, Au 0.001, Ag 0.002, Se 0.21, Te 2.22, Pb 1.12, HCl 92. First, diaminoethane hydrochloride was dissolved in 3 mol / L hydrochloric acid to prepare a precipitate solution A with a concentration of 85 g / L. Then, 150 L of the above-mentioned low-rhodium, high-impurity waste liquid was added to a reaction vessel, and the temperature was raised to 70°C. 15 g of sodium chlorate was added first, followed by precipitate solution A. After reacting for 8 hours, the solution was filtered to obtain rhodium precipitate. The rhodium precipitate was added to 1 mol / L dilute sulfuric acid, and the temperature was raised to 75°C. Then, a mixed solution of sodium chlorate and sodium chloride (1:4) was slowly added to dissolve it. The solution was added to an evaporator for concentration. When crystals precipitated in the solution, ice was added to rapidly cool the solution to 10°C. After standing for 24 hours, the solution was filtered. 25 g of diacetyl dioxime was added to the filtrate to remove palladium. After reacting for 2 hours, the solution was filtered. The filtrate was added to an evaporator for concentration. When the solution became viscous, a solution of [missing information - likely a specific concentration] was slowly added to the evaporator for concentration. A 40 g / L NaOH solution was prepared, and when the pH of the solution reached 7, 45 g of sodium hypochlorite was added. NaOH solution was then added to adjust the pH to 9. The reaction was allowed to proceed for 5 hours, followed by standing for 15 hours. The mixture was then filtered to obtain a hydrolyzed precipitate, which was washed six times with deionized water. The precipitate was then dissolved in 3 L of 3 mol / L dilute hydrochloric acid, and 90 g of sodium EVC was added. The reaction proceeded for 8 hours, followed by standing for 12 hours. The precipitate was then filtered, and the residue was washed twice with deionized water. The precipitate was then placed in a muffle furnace and calcined at 700 °C for 6 hours to obtain rhodium black. The rhodium black was boiled and washed with 400 ml of aqua regia for 20 minutes, cooled, and then filtered. The residue was washed three times with deionized water, dried, and then placed in a tube furnace for hydrogen reduction at 800 °C for 4 hours to obtain pure rhodium powder with a purity of 99.996%.

[0082] Example 6:

[0083] The main components of the rhodium-containing waste liquid (g / L) are: Rh 0.12, Ir 0.097, Ru 0.53, Pt 0.33, Pd 1.04, Au 0.002, Ag 0.002, Se 0.33, Te 2.53, Pb 1.16, HCl 99. First, dissolve dimethylamine hydrochloride in 3 mol / L hydrochloric acid to prepare a precipitate solution A with a concentration of 80 g / L. Then, add 150 L of the above low-rhodium, high-impurity waste liquid to a reaction vessel, heat to 70°C, add 30 g of sodium chlorate first, then add precipitate solution A, react for 6 hours, and filter to obtain rhodium precipitate. Add 1 mol / L dilute sulfuric acid to the rhodium precipitate, heat to 80°C, and then slowly add a mixed solution of sodium chlorate:sodium chloride = 1:4 to dissolve it. Add the solution to an evaporator for concentration, and when crystals precipitate in the solution, add ice to rapidly cool to 5°C, let stand for 24 hours, and then filter. Add 20 g of diacetyl dioxime to the filtrate to remove palladium, react for 1 hour, and then filter. Add the filtrate to an evaporator for concentration, and when the solution becomes viscous, slowly add a 4% concentration of diacetyl dioxime. 0 g / L NaOH solution was used. When the pH of the solution reached 7, 50 g of sodium hypochlorite was added. Then, NaOH solution was added to adjust the pH to 9. The reaction was allowed to proceed for 5 hours. After standing for 14 hours, the solution was filtered to obtain a hydrolyzed precipitate, which was washed 6 times with deionized water. The precipitate was then dissolved in 3 L of 2 mol / L dilute hydrochloric acid. After dissolution, 90 g of sodium EVC was added and the reaction proceeded for 8 hours. After standing for 12 hours, the solution was filtered, and the residue was washed twice with deionized water. The solution was then placed in a muffle furnace and calcined at 600 °C for 6 hours to obtain rhodium black. The rhodium black was boiled and washed with 400 ml of aqua regia for 30 minutes. After cooling, the solution was filtered, and the residue was washed 3 times with deionized water. After drying, the solution was placed in a tube furnace and reduced with hydrogen at 700 °C for 6 hours to obtain pure rhodium powder with a purity of 99.994%.

[0084] The above provides a detailed description of a method for enriching and recovering rhodium from low-rhodium, high-impurity waste liquid, as provided in the embodiments of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and its core ideas; furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

[0085] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0086] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0087] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0088] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A method for enriching and recovering rhodium from low-rhodium, high-impurity waste liquid, characterized in that, The process includes the following steps: S1) Prepare precipitation solution A; The specific steps are as follows: Precipitant A is mixed with hydrochloric acid with a concentration of 2-3 mol / L to prepare precipitant solution A with a concentration of 80-90 g / L; The precipitant A is one or more of tetramethylethylenediamine hydrochloride, diaminoethane hydrochloride, or dimethylamine hydrochloride; S2) After heating the low-rhodium, high-impurity waste liquid to a certain temperature, add additive A, and then slowly add the precipitate solution A obtained in S1). After reacting for a period of time, cool and filter and wash to obtain rhodium precipitate. Low-rhodium, high-impurity waste liquid is the tailings produced after the extraction of platinum and palladium in industrial production. The amount of additive A added is such that the mass ratio of additive A to the rhodium content in the low-rhodium, high-impurity waste liquid is 1:

1. The additive A is one or more of hydrogen peroxide, sodium chlorate, and sodium hypochlorite; S3) After mixing the rhodium precipitate obtained in S2) with dilute sulfuric acid, heat it to a certain temperature, and then gradually add the mixed solution until the rhodium precipitate is completely dissolved to obtain a solution; The mixed solution has a mass ratio of sodium chlorate to sodium chloride of 1:

4. S4) The solution obtained in S3) is evaporated and concentrated. When crystals precipitate in the solution system, ice is added to rapidly cool to the final temperature. After standing, it is filtered to obtain filtrate A. S5) Add precipitant B to the filtrate A obtained in S4) to remove palladium, react for a period of time, and then filter to obtain filtrate B; The precipitant B is diacetyldioxime; S6) Evaporate and concentrate the filtrate B obtained in S5) until the solution system becomes viscous. Then slowly add NaOH solution to adjust the pH value and add additive C. Then continue to add NaOH solution to adjust the pH value. After reacting for a period of time, filter after standing. Wash the hydrolyzed precipitate with deionized water several times. The additive C is sodium hypochlorite; S7) Dissolve the hydrolyzed precipitate after washing in S6) in dilute hydrochloric acid. After the hydrolyzed precipitate is completely dissolved, add reducing agent A. After reacting for a period of time, let it stand and filter to obtain rhodium slag. Wash the rhodium slag with deionized water several times. The reducing agent A is sodium EVC; S8) The rhodium slag obtained in S7) is calcined to obtain rhodium black. The rhodium black is then boiled and washed with aqua regia, cooled and filtered. The filter residue is washed multiple times with deionized water, dried, and then reduced by hydrogen gas to obtain pure rhodium powder.

2. The method according to claim 1, characterized in that, The method for dissolving the rhodium precipitate in S3) is as follows: first, add the rhodium precipitate and dilute sulfuric acid with a concentration of 1 mol / L to the reaction vessel, heat to 60~80℃, and then add the mixed solution. The mass ratio of the mixed solution added is: mixed solution: rhodium = 2~3:

1.

3. The method according to claim 1, characterized in that, The final temperature in S4) is 5-10℃, and the settling time is 22-26h.

4. The method according to claim 1, characterized in that, The amount of precipitant B added in S5) is: precipitant B: palladium = 2~3:

1.

5. The method according to claim 1, characterized in that, The evaporation and concentration process in S6) is as follows: after concentrating the solution system to a viscous state, slowly add NaOH solution to adjust the pH. When the pH is adjusted to 6-7, add additive C, and then continue to add NaOH solution to adjust the pH to 9-10. React for 4-6 hours, let stand for 12-15 hours, filter, and wash the hydrolyzed precipitate with deionized water 4-6 times. Evaporation and concentration are required before neutralization and hydrolysis. The concentration endpoint is when the solution is viscous.

6. The method according to claim 5, characterized in that, The addition point of additive C is when the solution pH is 6~7, and the mass ratio of additive C added is: additive C: rhodium = 2~3:

1.

7. The method according to claim 1, characterized in that, The amount added in S7) is in the following mass ratio: reducing agent A: rhodium = 5~6:

1.

8. The method according to claim 1, characterized in that, The specific process of S8 is as follows: calcination at 600~700℃ for 4~6h to obtain rhodium black, boiling and washing the rhodium black with aqua regia for 20~30min, cooling and filtering, washing the filter residue with deionized water multiple times, drying and placing it in a tube furnace, and reducing it in a hydrogen atmosphere at 600~800℃ for 4~6h.

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