A process for the recovery of metallic rhodium from rhodium-containing organic materials

Abstract

The present application relates to the technical field of precious metal recovery, and provides a method for recovering metal rhodium from rhodium-containing organic materials. The present application directly takes the rhodium-containing organic materials as the processing object, transfers the rhodium from the organic phase to the aqueous phase through polymer aqueous solution washing, then uses tin salt as an active agent for organic extractant extraction, and the obtained rhodium-containing organic phase is back-extracted by hydrochloric acid, so that the enrichment and purification of rhodium can be realized. The method provided by the present application has the advantages of simple process flow, high recovery rate and purity of precious metals, and the polymer, extractant, tin salt solution and hydrochloric acid can be recycled, which avoids the consumption of a large amount of acid and alkali, reduces the discharge of waste water and solid waste, and has the advantages of green, economy and scalability.

Description

Technical Field

[0001] This invention relates to the field of precious metal recycling technology, and in particular to a method for recovering metallic rhodium from rhodium-containing organic materials. Background Technology

[0002] With the rapid development of the global oil industry, precious metal catalysts play a crucial role in downstream petrochemical processes. However, directly discarding deactivated catalysts not only results in a huge waste of precious metal resources but also causes environmental pollution. Therefore, developing efficient and green precious metal recovery technologies has become one of the core requirements for the sustainable development of the petrochemical industry.

[0003] Hydroformylation, a key conversion pathway in the petrochemical industry linking olefins and aldehydes, is widely used in the production of bulk chemicals such as butanol, octanol, and plasticizers. Its products are also core raw materials for fine chemicals and pharmaceutical intermediates. Currently, the mainstream catalysts for hydroformylation are homogeneous complexes formed by rhodium (Rh) and phosphine ligands such as triphenylphosphine (TPP). These catalytic systems have low rhodium loading and are mixed with a large amount of organic matrix, making traditional precious metal catalyst recovery technologies difficult to apply directly, with recovery efficiencies generally below 90%.

[0004] Currently, the main methods for recovering homogeneous rhodium catalysts include the following: Incineration method: Organic matter is decomposed by high-temperature incineration, causing rhodium to accumulate in the ash. Metallic rhodium is then obtained through reduction and purification. This method requires impregnation of the incinerated ash with mixed acid, resulting in large quantities of waste gas, solid waste, and waste acid.

[0005] Extraction method: This method utilizes organic extractants (such as halomethanes and alkylphosphine oxides) to form complexes with rhodium, and then enriches the catalyst through back-extraction. For example, related technologies use a dichloromethane-hydrogen iodide system to extract carbonyl synthesis waste catalysts, achieving a high recovery rate. However, a significant amount of extractant remains in the organic phase, affecting subsequent processing.

[0006] Adsorption method: This method involves the selective adsorption of rhodium-phosphine complexes by adsorbents (such as magnesium silicate or ion exchange resins), followed by elution and dissolution for purification. For example, related technologies use magnesium silicate to adsorb rhodium-phosphine complexes, achieving a recovery rate >95%, but the adsorption capacity is limited, requiring frequent regeneration.

[0007] Taking the low-pressure rhodium phosphine carbonyl synthesis process as an example, its waste liquid mainly contains a large amount of solvent, a small amount of high-boiling aldehydes and ketones, a small amount of triphenylphosphine ligands, and trace amounts of rhodium (50~800ppm). In existing technologies, the waste liquid is often concentrated by vacuum distillation and other methods, and then rhodium is recovered by extraction, adsorption and other methods. However, due to factors such as low rhodium concentration and complex organic matrix, the overall recovery rate is low.

[0008] In summary, current methods for recovering metallic rhodium cannot simultaneously balance recovery efficiency, production costs, and environmental requirements, making it difficult to achieve efficient enrichment and separation of trace amounts of rhodium from homogeneous catalysts in hydroformylation reactions. Summary of the Invention

[0009] In view of this, the present invention provides a method for recovering metallic rhodium from rhodium-containing organic materials. The method provided by the present invention has a high rhodium recovery rate, high product purity, and various solutions and extractants can be recycled multiple times, resulting in low cost and environmental friendliness.

[0010] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A method for recovering metallic rhodium from rhodium-containing organic materials includes the following steps: Rhodium-containing organic materials and polymer aqueous solutions are mixed and then washed and allowed to stand for separation to obtain a rhodium-containing polymer aqueous solution; the polymer in the polymer aqueous solution is poly(N-isopropylacrylamide-co-acrylic acid); the concentration of the polymer aqueous solution is 0.2~3wt%; the mass of the polymer aqueous solution is 0.1~0.5 times the mass of the rhodium-containing organic materials; the washing temperature is 60~90℃ and the time is 30~180min; The rhodium-containing polymer aqueous solution was heated and then filtered while hot to obtain a rhodium-containing polymer solid. The rhodium-containing polymer solid is dissolved in a tin salt solution, followed by extraction with an organic extractant to obtain a rhodium-containing organic phase; the concentration of the tin salt solution is 1-5 mol / L; the mass of the tin salt solution is 4-15 times the mass of the polymer; the mass of the organic extractant is 0.2-2 times the mass of the tin salt solution; the organic extractant is prepared from a quaternary ammonium salt and a fatty acid. The rhodium-containing organic phase is back-extracted with hydrochloric acid to obtain a rhodium-containing hydrochloric acid solution phase; the concentration of the hydrochloric acid is 3~12 mol / L; the total mass of the hydrochloric acid is 1~2.5 times the mass of the organic extractant.

[0011] Preferably, the rhodium-containing organic material is a reaction solution for hydroformylation; the Rh content in the rhodium-containing organic material is 10~800 ppm.

[0012] Preferably, the mass fraction of acrylic acid in the poly(N-isopropylacrylamide-co-acrylic acid) is 5~25wt%.

[0013] Preferably, the temperature for static stratification is 10~20℃; the final temperature for heating is 50~90℃.

[0014] Preferably, the tin salt solution is a stannous chloride solution.

[0015] Preferably, the quaternary ammonium salt is methyltrioctylammonium oleate; and the fatty acid is oleic acid.

[0016] Preferably, the hot filtration also yields an aqueous phase; the back-extraction also yields a recovered extractant phase; the aqueous phase and the recovered extractant phase are recycled.

[0017] Preferably, the extraction further yields a polymer-containing tin salt solution phase; the polymer-containing tin salt solution phase is heated and filtered while hot to obtain a recovered polymer and a recovered tin salt solution; the recovered polymer and the recovered tin salt solution are recycled.

[0018] Preferably, after obtaining the rhodium-containing hydrochloric acid solution phase, the method further includes mixing the rhodium-containing hydrochloric acid solution phase, the adsorbent, and the reducing agent for adsorption-reduction treatment, performing solid-liquid separation on the resulting treated liquid to obtain a rhodium-containing precipitate, and calcining the rhodium-containing precipitate to obtain metallic rhodium.

[0019] Preferably, the adsorbent is one or more of biochar and powdered activated carbon; the mass of the adsorbent is 0.5~2wt% of the mass of the hydrochloric acid solution phase. The reducing agent is one or more of sulfur dioxide, sodium bisulfite, formic acid, and hydrazine hydrate; The roasting temperature is 400~800℃ and the time is 60~180 min.

[0020] This invention provides a method for recovering metallic rhodium from rhodium-containing organic materials, comprising the following steps: mixing the rhodium-containing organic material and a polymer aqueous solution, followed by washing and settling to obtain a rhodium-containing polymer aqueous solution; the polymer in the polymer aqueous solution is a copolymer of N-isopropylacrylamide and acrylic acid; the concentration of the polymer aqueous solution is 0.2~3 wt%; the mass of the polymer aqueous solution is 0.1~0.5 times the mass of the rhodium-containing organic material; the washing temperature is 60~90℃, and the washing time is 30~180 min; the rhodium-containing polymer aqueous solution is heated and filtered while hot to obtain a rhodium-containing polymer solid; the rhodium-containing polymer solid is dissolved in a tin salt solution, and then an organic extractant is added for extraction to obtain a rhodium-containing organic phase; the concentration of the tin salt solution is 1~5%. The concentration of the tin salt solution is 3-12 mol / L; the mass of the tin salt solution is 4-15 times the mass of the polymer; the mass of the organic extractant is 0.2-2 times the mass of the tin salt solution; the organic extractant is prepared from quaternary ammonium salt and fatty acid; the rhodium-containing organic phase is back-extracted with hydrochloric acid to obtain a rhodium-containing hydrochloric acid solution phase; the concentration of the hydrochloric acid is 3-12 mol / L; the total mass of the hydrochloric acid is 1-2.5 times the mass of the organic extractant. The beneficial effects of this invention are: This invention abandons the traditional process route of using strong acid to leach waste solids and then enriching and purifying them. Instead, it directly uses rhodium-containing organic materials such as the hydroformylation original reaction solution as the treatment object. Through polymer washing, rhodium is transferred from the organic phase to the aqueous phase. Subsequently, through extraction and back-extraction, rhodium enrichment and purification can be achieved, avoiding the problem of large-scale consumption of strong acid and waste acid discharge. The process is green and environmentally friendly.

[0021] This invention uses poly(N-isopropylacrylamide-co-acrylic acid) as a complexing agent, which has temperature-sensitive properties, exhibiting water solubility at low temperatures and decreasing water solubility at high temperatures. This property allows for convenient recovery of the complexing agent. Tin salt is used as an activator to convert rhodium into a complex anion that is more easily extracted by the organic phase, solving the problems of difficult extraction and low extraction rate of ordinary rhodium chloride complexes, thereby achieving efficient enrichment of rhodium. Using the method of this invention, rhodium powder with a purity ≥95% and a total recovery rate ≥97% can be obtained from organic materials with a rhodium content of 10~800ppm.

[0022] Furthermore, in the method provided by this invention, the polymer, organic extractant, tin salt solution, and hydrochloric acid can all be recycled. Continuous application experiments in Examples 3-7 show that after five cycles of recycling, the rhodium recovery rate remains stable at over 98.0%. The complete recycling of the polymer, extractant, tin salt solution, and hydrochloric acid significantly reduces raw material consumption and wastewater discharge, thereby lowering costs.

[0023] In summary, the method provided by this invention has a simple process flow, low dependence on equipment, high recovery rate and purity of precious metals, and avoids the consumption of large amounts of acids and alkalis, reducing the discharge of wastewater and solid waste. It has the advantages of being green, economical and scalable. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of the present invention for recovering metallic rhodium from rhodium-containing organic materials. Detailed Implementation

[0025] This invention provides a method for recovering metallic rhodium from rhodium-containing organic materials, comprising the following steps: Rhodium-containing organic materials and polymer aqueous solutions are mixed and then washed and allowed to stand for separation to obtain a rhodium-containing polymer aqueous solution; the polymer in the polymer aqueous solution is poly(N-isopropylacrylamide-co-acrylic acid); the concentration of the polymer aqueous solution is 0.2~3wt%; the mass of the polymer aqueous solution is 0.1~0.5 times the mass of the rhodium-containing organic materials; the washing temperature is 60~90℃ and the time is 30~180min; The rhodium-containing polymer aqueous solution was heated and then filtered while hot to obtain a rhodium-containing polymer solid. The rhodium-containing polymer solid is dissolved in a tin salt solution, followed by extraction with an organic extractant to obtain a rhodium-containing organic phase; the concentration of the tin salt solution is 1-5 mol / L; the mass of the tin salt solution is 4-15 times the mass of the polymer; the mass of the organic extractant is 0.2-2 times the mass of the tin salt solution; the organic extractant is prepared from a quaternary ammonium salt and a fatty acid. The rhodium-containing organic phase is back-extracted with hydrochloric acid to obtain a rhodium-containing hydrochloric acid solution phase; the concentration of the hydrochloric acid is 3~12 mol / L; the total mass of the hydrochloric acid is 1~2.5 times the mass of the organic extractant.

[0026] Figure 1 This is a process flow diagram of the present invention for recovering metallic rhodium from rhodium-containing organic materials. The following is in conjunction with... Figure 1 Please provide a detailed explanation.

[0027] This invention involves mixing a rhodium-containing organic material and a polymer aqueous solution, followed by sequential washing and settling to obtain a rhodium-containing polymer aqueous solution. In this invention, the rhodium-containing organic material is preferably a reaction solution for hydroformylation, specifically a reaction solution for the hydroformylation of allyl acetate or allyl alcohol. Besides rhodium, the hydroformylation reaction solution also includes an organic solvent, reaction product, water, reaction raw materials, and a phosphine ligand. The reaction raw materials are allyl acetate or allyl alcohol, and the corresponding reaction product is 4-acetoxybutanal or 4-hydroxybutanal. The phosphine ligand is specifically triphenylphosphine. In this invention, the Rh content in the rhodium-containing organic material is preferably 10-800 ppm, more preferably 50-800 ppm, and even more preferably 300-450 ppm. In this invention, the polymer is poly(N-isopropylacrylamide-co-acrylic acid), specifically a copolymer of N-isopropylacrylamide and acrylic acid. The mass fraction of acrylic acid in the poly(N-isopropylacrylamide-co-acrylic acid) is preferably 5-25%, specifically 10%, 15%, or 20%. The number-average molecular weight of the poly(N-isopropylacrylamide-co-acrylic acid) is preferably 8000-9000, 8754 in the example; the weight-average molecular weight is 14000-15000, 14882 in the example; and the molecular weight distribution is preferably 1.5-2, 1.7 in the example. The poly(N-isopropylacrylamide-co-acrylic acid) has temperature-sensitive properties, exhibiting water solubility at low temperatures and decreasing water solubility at high temperatures (solubility decreases above 33°C). Using this polymer, the present invention can conveniently enrich rhodium and simultaneously achieve convenient polymer recovery.

[0028] In this invention, the concentration of the polymer aqueous solution is 0.2-3 wt%, specifically 0.2 wt%, 0.5 wt%, or 3 wt%; the mass of the polymer aqueous solution is 0.1-0.5 times the mass of the rhodium-containing organic material, specifically 0.1, 0.2, or 0.5 times.

[0029] In this invention, the washing temperature is 60-90°C, specifically 60°C, 80°C, or 90°C; the washing time is preferably 30-180 min, specifically 30, 60, or 180 min; the washing is preferably carried out under stirring conditions; the washing is carried out in a washing vessel; the settling and layering temperature is preferably 10-20°C, more preferably 15°C; the settling and layering time is preferably 10-20 min, more preferably 15 min. In a specific embodiment of this invention, after washing, it is preferable to cool to 10-20°C and continue stirring for 10-20 min, followed by settling and layering. The upper organic phase obtained after settling and layering can enter the subsequent process of hydroformylation reaction, and the lower rhodium-containing polymer aqueous solution enters the next step of recovery.

[0030] After obtaining the rhodium-containing polymer aqueous solution, the present invention heats the rhodium-containing polymer aqueous solution and filters it while hot to obtain the rhodium-containing polymer solid. In the present invention, the endpoint temperature of the heating is preferably 50~90℃, more preferably 60℃; the polymer has temperature-sensitive characteristics, and its solubility decreases as the temperature increases. The present invention separates the rhodium-containing polymer from the solution by heating and filtering while hot to filter out the polymer solid that precipitates due to the change in solubility; the aqueous phase obtained by hot filtration can be recycled for the preparation of new polymer aqueous solutions, improving material utilization and reducing wastewater discharge.

[0031] After obtaining the rhodium-containing polymer solid, this invention dissolves the rhodium-containing polymer solid in a tin salt solution, and then adds an organic extractant for extraction to obtain a rhodium-containing organic phase. In this invention, the tin salt solution is preferably a stannous chloride (SnCl2) solution; the concentration of the tin salt solution is 1~5 mol / L, specifically 1, 3, or 5 mol / L; the mass of the tin salt solution is 4~15 times the mass of the polymer, specifically 4, 10, or 15 times. This invention preferably uses SnCl2 as an activator to convert rhodium to [Rh(SnCl3)5]. 4- It exists in a form that is easier to extract than rhodium chloride complexes, thus improving the extraction rate.

[0032] In this invention, the organic extractant is prepared from a quaternary ammonium salt and a fatty acid, wherein the quaternary ammonium salt is methyltrioctylammonium oleate; the fatty acid is oleic acid; the molar ratio of the quaternary ammonium salt to the fatty acid is preferably 1:1 to 1.5; in a specific embodiment of this invention, it is preferable to mix the quaternary ammonium salt and oleic acid for reaction, wash the resulting product with water, and collect the organic phase to obtain the organic extractant; the reaction temperature is preferably 70 to 90°C, specifically 80°C; this invention preferably uses the above-mentioned organic extractant, which can improve the extraction efficiency and achieve multiple recycling; the mass of the organic extractant is 0.2 to 2 times the mass of the tin salt solution, preferably 0.4 times; the extraction time is preferably 15 to 60 min, more preferably 30 min; the extraction temperature is preferably room temperature; the extraction is preferably carried out under stirring conditions; the extraction is carried out in a washing vessel.

[0033] After extraction, the present invention preferably allows the mixture to stand and separate into a lower aqueous phase containing polymer-containing tin salt and an upper organic phase containing rhodium. The polymer-containing tin salt aqueous phase is preferably heated to precipitate the polymer, followed by hot filtration to obtain polymer solids and a tin salt solution. The endpoint temperature of the heating is preferably 50-90°C, more preferably 60°C. The separated polymer solids and tin salt solution are preferably recycled separately to reduce the discharge of solid and liquid waste.

[0034] After obtaining the rhodium-containing organic phase, the present invention preferably uses hydrochloric acid to back-extract the rhodium-containing organic phase to obtain a rhodium-containing hydrochloric acid solution phase. In the present invention, the concentration of the hydrochloric acid is 3~12 mol / L, preferably 5 mol / L; the total mass of the hydrochloric acid is 1~2.5 times the mass of the organic extractant, preferably 1.5 times; in a specific embodiment of the present invention, the hydrochloric acid is preferably divided into 2~5 equal parts, and the organic phase is back-extracted multiple times, and the rhodium-containing hydrochloric acid solution phase obtained from the multiple back-extractions is combined; the back-extraction is preferably carried out under stirring conditions, and the back-extraction temperature is preferably room temperature; the back-extraction is carried out in a washing tank.

[0035] In this invention, the back-extraction also yields a recovered extractant phase, which is preferably recycled.

[0036] After obtaining the rhodium-containing hydrochloric acid solution phase, the present invention mixes the rhodium-containing hydrochloric acid solution phase, adsorbent, and reducing agent for adsorption-reduction treatment, and performs solid-liquid separation on the resulting treated liquid to obtain a rhodium-containing precipitate. In the present invention, the adsorbent is preferably one or more of biochar and powdered activated carbon; the mass of the adsorbent is preferably 0.5~2wt% of the mass of the rhodium-containing hydrochloric acid solution phase; the reducing agent is preferably one or more of sulfur dioxide, sodium bisulfite, formic acid, and hydrazine hydrate; the adsorption-reduction treatment time is preferably 5~30 min; in a specific embodiment of the present invention, it is preferable to first add the adsorbent to the hydrochloric acid solution phase, and then continuously introduce sulfur dioxide gas into the system for 5~30 min to reduce and adsorb Rh ions; the solid-liquid separation method is preferably filtration, and the solid product obtained by the solid-liquid separation is the rhodium-containing precipitate, and the liquid product is a hydrochloric acid solution, which can be directly recycled and reused, reducing waste acid emissions.

[0037] After obtaining the rhodium-containing precipitate, the present invention calcines the rhodium-containing precipitate to obtain metallic rhodium. In the present invention, the calcination temperature is preferably 400~800℃, more preferably 650℃, and the calcination time is preferably 60~180min, more preferably 120min; after calcination, a gray-black metallic rhodium powder is obtained.

[0038] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0039] Preparation Example 1: Preparation of Polymers 200g of tert-butanol solvent, 153.0g of N-isopropylacrylamide, and 27.0g of acrylic acid were added to a reactor. Nitrogen gas was purged to purge air for 30 min. The material was heated to 70℃ and kept at this temperature for 12 h. During this period, 15g of azobisisobutyronitrile (AIBN) initiator was added to the reactor every 30 min. After the reaction was completed, 400g of n-hexane was added to the reactor and stirred thoroughly to precipitate the polymer. The solid was filtered out, washed with 80℃ hot water, and dried to obtain a white powdery solid (i.e., poly(N-isopropylacrylamide-co-acrylic acid)). The reaction conversion rate was 87%.

[0040] The polymer was sampled, and the mass fraction of acrylic acid in the polymer was determined to be 14.7 wt% by acid-base titration. The number average molecular weight of the polymer was determined to be 8754, the weight average molecular weight was 14882, and the molecular weight distribution was 1.7 by gel filtration chromatography.

[0041] Preparation Example 2: Preparation of Organic Extractants 4.06 kg (1 eq, 10 mol, 404.16 Da) of methyltrioctylammonium chloride and 4.24 kg (1.5 eq, 15 mol, 282.46 Da) of oleic acid were added to the reactor and stirred until homogeneous. The mixture was then heated to 80 °C and maintained for 1 h. After cooling to room temperature, the mixture was washed with deionized water until the pH of the aqueous phase was greater than 6. The organic phase was then separated and collected to obtain the organic extractant.

[0042] Preparation Example 3: Hydroformylation reaction was carried out using allyl acetate as a raw material. 89.09 kg (890 mol, 1 eq, 100.1 Da) of allyl acetate, 115.45 kg of toluene solvent, and 13.0 kg (containing 0.6% rhodium, 0.00085 eq, with triphenylphosphine as the ligand) of catalyst solution were added to a high-pressure reactor. 37.38 kg (1335 mol, 1.5 eq, 28 Da) of CO and 2.67 kg (1335 mol, 1.5 eq, 2 Da) of H2 were then introduced into the reactor. The stirring and heating functions were activated, and the material was heated to 85°C and stirred for 5 hours. After the reaction, the organic phase was sampled, and the composition was analyzed by gas chromatography with internal standard method according to GB / T 9722-2023. The sample contained 44.5 wt% toluene solvent, 42.8 wt% 4-acetoxybutyraldehyde product, 7.4 wt% water, 0.8 wt% allyl acetate raw material, and 0.2 wt% triphenylphosphine. The sample was processed according to the method in HJ 700-2014, and the Rh content was detected by inductively coupled plasma mass spectrometry. The calculated Rh content in the organic phase solution was 302.6 ppm.

[0043] Preparation Example 4: Hydroformylation reaction was carried out using allyl alcohol as a raw material. 85.99 kg (1480 mol, 1 eq, 58.1 Da) of allyl alcohol, 103.2 kg of toluene solvent, and 18.8 kg of catalyst solution (containing 0.6% rhodium, 0.00074 eq, and triphenylphosphine as the ligand) were added to a high-pressure reactor. 62.16 kg (2220 mol, 1.5 eq, 28 Da) of CO and 4.44 kg (2220 mol, 1.5 eq, 2 Da) of H2 were then introduced into the reactor. The stirring and heating functions were activated, and the reactor temperature was raised to 85°C. The reaction was stirred for 5 hours. After the reaction, the organic phase was sampled, and the composition was analyzed by gas chromatography with internal standard method according to GB / T 9722-2023. The sample contained 41.1 wt% toluene solvent, 47.5 wt% 4-hydroxybutyraldehyde product, 6.9 wt% water, 0.5 wt% allyl alcohol, and 0.2 wt% triphenylphosphine. The sample was processed according to the method in HJ 700-2014, and the Rh content was detected by inductively coupled plasma mass spectrometry. The calculated Rh content in the organic phase solution was 449.2 ppm.

[0044] Example 1: Treatment of the hydroformylation reaction solution in Preparation Example 3 250 kg of rhodium-containing organic material (Rh content of 302.6 ppm) obtained in Preparation Example 3 was transferred to the first washing vessel. 250 g of poly(N-isopropylacrylamide-co-acrylic acid) obtained in Preparation Example 1 was dissolved in water to prepare a 0.5 wt% polymer aqueous solution (0.2 times the amount of rhodium-containing organic material), which was then added to the washing vessel. Stirring was started, and the material in the first washing vessel was heated to 80°C. After stirring and washing for 60 min, the material was cooled to 15°C and stirred for another 15 min. Then, stirring was stopped, and the mixture was allowed to stand and separate into layers. The upper organic phase was separated, and a sample of the organic phase was taken. The organic phase was processed according to the method in HJ 700-2014, and the Rh content was detected using inductively coupled plasma mass spectrometry. The calculated Rh content in the organic phase solution was 2.42 ppm, with an extraction efficiency of 99.2%.

[0045] The rhodium-containing polymer aqueous solution in the reactor was rapidly heated to 60°C, and the precipitated rhodium-containing polymer solid was filtered off while hot. The aqueous phase could be recycled. In the second washing reactor, the collected rhodium-containing polymer solid was dissolved in 2.5 kg (10 times the polymer concentration) of a 3 mol / L SnCl2 solution, and 1 kg (0.4 times the SnCl2 solution concentration) of the organic extractant obtained in Preparation Example 2 was weighed and added to the reactor. After stirring and mixing for 30 min, the organic extractant turned golden yellow. The Rh content of the organic phase was measured to be 7.47%, and the extraction efficiency was 99.6%. After standing and separating the layers, the lower aqueous phase was transferred to the third washing reactor. After heating to 60°C, the polymer and SnCl2 solution were separated and recovered separately.

[0046] For the rhodium-containing organic phase in the second washing vessel, 0.5 kg of 5 mol / L hydrochloric acid was added and stirred for 30 min. The mixture was then allowed to stand and separate into layers, with the lower aqueous phase being separated. The washing process was repeated twice (using a total of 1.5 kg of hydrochloric acid, 1.5 times the amount of organic extractant) until the organic phase changed from golden yellow to colorless. Three batches of rhodium-containing hydrochloric acid solution phases were combined. Samples of the recovered extractant phase and the rhodium-containing hydrochloric acid solution phase were taken and tested. The Rh contents were 0.53% and 4.95%, respectively, with a separation efficiency of 99.3%. 50 g of activated carbon was added and stirred, and SO2 gas was bubbled into the liquid for 15 min until all rhodium ions were reduced and adsorbed. The solid in the system was separated by filtration, and the remaining hydrochloric acid was recovered and recycled. The solid was then calcined in a muffle furnace at 650 °C for 120 min to obtain 76.2 g of Rh powder with a purity of 97.4% and a total recovery rate of 98.1%.

[0047] Example 2: Treatment of the hydroformylation reaction solution in Preparation Example 4 A total of 250 kg of material (Rh content of 449.2 ppm) obtained in Preparation Example 4 was transferred to the first washing vessel. 250 g of the polymer obtained in Preparation Example 1 was dissolved in water to prepare a 0.5 wt% polymer aqueous solution (0.2 times the amount of organic material), which was then added to the washing vessel. Stirring was started, and the material in the first washing vessel was heated to 80°C. After stirring and washing for 60 min, the material was cooled to 15°C and stirred for another 15 min. Then, stirring was stopped, and the mixture was allowed to stand and separate into layers. The upper organic phase was separated, and a sample of the organic phase was taken. The organic phase was processed according to the method in HJ 700-2014, and the Rh content was detected using inductively coupled plasma mass spectrometry. The calculated Rh content in the organic phase solution was 4.04 ppm, with an extraction efficiency of 99.1%. The rhodium-containing polymer aqueous solution in the reactor was rapidly heated to 60°C, and the precipitated polymer solid was filtered off while hot. The aqueous phase was recycled. In the second washing reactor, the collected polymer solid was dissolved in 2.5 kg (10 times the polymer) of a 3 mol / L SnCl2 solution, and 1 kg (0.4 times the brine) of the organic extractant obtained in Preparation Example 2 was weighed and added to the reactor. After stirring and mixing for 30 min, the organic extractant turned golden yellow. The Rh content of the organic phase was measured to be 11.06%, and the extraction efficiency was 99.4%. After standing and separating the layers, the lower aqueous phase was transferred to the third washing reactor. The material in the third washing reactor was stirred and rapidly heated to 60°C, and the polymer and SnCl2 solution were separated and recovered separately.

[0048] For the organic solution in the second washing vessel, 0.5 kg of 5 mol / L hydrochloric acid was added and stirred for 30 min. The mixture was then allowed to stand and separate into layers, with the lower aqueous phase being separated. The washing process was repeated twice (totaling 1.5 kg, 1.5 times the amount of organic extractant) until the organic phase changed from golden yellow to colorless. Three batches of rhodium-containing hydrochloric acid solution phases were combined. Samples of the recovered extractant phase and the rhodium-containing hydrochloric acid solution phase were taken and tested. The Rh contents were 0.55% and 7.34%, respectively, with a separation efficiency of 99.5%. 15 g of activated carbon was added and stirred, and SO2 gas was bubbled into the liquid for 15 min until all rhodium ions were reduced and adsorbed. The solid in the system was separated by filtration. The remaining hydrochloric acid was recovered and recycled. The solid was calcined in a muffle furnace at 650℃ for 120 min to obtain 112.6 g of Rh powder with a purity of 97.2% and a total recovery rate of 98.2%.

[0049] Example 3: Recycling of polymer, aqueous phase, organic extractant, and hydrochloric acid Hydroformylation experiments were performed according to the same scheme as in Preparation Example 3. Using this as raw material, and based on the scheme of Example 1, the polymer recovered in Example 1, aqueous phase, organic extractant, and hydrochloric acid were used to complete the purification of Rh.

[0050] The first reaction vessel contains the residual aqueous phase after the polymer precipitation. 250 kg of the prepared hydroformylation reaction solution and the polymer recovered in Example 1 are added. The steps and conditions of stirring, mixing, heating, and washing are the same as in Example 1. After washing, the upper organic material is separated.

[0051] After heating the polymer aqueous solution in the reactor to 60°C, the precipitated rhodium-containing polymer solid was filtered off while hot, and the aqueous phase could be recycled. In the second washing reactor, the collected rhodium-containing polymer solid was dissolved in the SnCl2 solution recovered in Example 1, and the organic extractant recovered in Example 1 was added. The washing steps and conditions were the same as in Example 1. After washing, the mixture was allowed to stand and separate into layers. The lower aqueous phase was separated into a third washing reactor, and after heating to 60°C, the polymer and SnCl2 solution were separated and recovered separately.

[0052] The rhodium-containing organic phase in the second washing vessel was added with hydrochloric acid recovered in Example 1. The subsequent washing, separation, reduction, calcination and other steps and conditions were kept the same as in Example 1. The organic extractant and hydrochloric acid used in the recovery process were also included.

[0053] Example 4 Hydroformylation experiments were performed according to the same scheme as in Preparation Example 3. Using this as raw material, and based on the scheme of Example 3, the polymer recovered in Example 3, aqueous phase, extractant, and hydrochloric acid were used to complete the purification of Rh.

[0054] Example 5 Hydroformylation experiments were performed according to the same scheme as in Preparation Example 3. Using this as raw material, and based on the scheme of Example 4, the polymer recovered in Example 4, aqueous phase, extractant, and hydrochloric acid were used to complete the purification of Rh.

[0055] Example 6 Hydroformylation experiments were performed according to the same scheme as in Preparation Example 3. Using this as raw material, and based on the scheme of Example 5, the polymer recovered in Example 5, aqueous phase, extractant, and hydrochloric acid were used to complete the purification of Rh.

[0056] Example 7 Hydroformylation experiments were performed according to the same scheme as in Preparation Example 3. Using this as raw material, and based on the scheme of Example 6, the polymer recovered in Example 6, aqueous phase, extractant, and hydrochloric acid were used to complete the purification of Rh.

[0057] Examples 8-9: Polymer Aqueous Solutions The hydroformylation reaction solution was prepared according to the procedure in Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When washing the hydroformylation reaction solution with a polymer aqueous solution, the concentration and amount of the polymer aqueous solution were changed from 0.5 wt% and 50 kg (0.2 times) in Example 1 to 0.2 wt% and 125 kg (0.5 times) in Example 8, and 3.0 wt% and 25 kg (0.1 times) in Example 9, respectively. Other processing conditions and steps remained consistent with Example 1.

[0058] Examples 10-11: Washing conditions of polymer aqueous solution The hydroformylation reaction solution was prepared according to the method described in Example 3, and Rh in the reaction solution was recovered according to the method described in Example 1. When washing the hydroformylation reaction solution with a polymer aqueous solution, the washing temperature and time were changed from 80°C and 60 min in Example 1 to 60°C and 180 min in Example 10, and 90°C and 30 min in Example 11, respectively. Other processing conditions and steps remained the same as in Example 1.

[0059] Examples 12-13: Tin Salt Solutions The hydroformylation reaction solution was prepared according to the procedure in Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When using tin salt solution to dissolve the polymer, the concentration and amount of tin salt solution were changed from 3 mol / L and 2.5 kg (10 times) in Example 1 to 1 mol / L and 3.75 kg (15 times) in Example 12, and 5 mol / L and 1.0 kg (4 times) in Example 13, respectively. Other processing conditions and steps remained the same as in Example 1.

[0060] Examples 14-15: Extractant Dosage The hydroformylation reaction solution was prepared according to the procedure in Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When extracting the tin salt solution with an organic extractant, the amount of extractant was changed from 1 kg (0.4 times) in Example 1 to 5 kg (2 times) in Example 14 and 0.5 kg (0.2 times) in Example 15, respectively. Other processing conditions and steps were consistent with those in Example 1.

[0061] Examples 16-17: Hydrochloric acid dosage The hydroformylation reaction solution was prepared according to the procedure in Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When washing the extractant solution with hydrochloric acid, the concentration and amount of hydrochloric acid were changed from 5 mol / L and 1.5 kg (1.5 times) in Example 1 to 3 mol / L and 2.5 kg (2.5 times) in Example 16, and 12 mol / L and 1.0 kg (1 times) in Example 17, respectively. Other treatment conditions and procedures remained consistent with Example 1.

[0062] Comparative Examples 1-2: Polymer Aqueous Solutions The hydroformylation reaction solution was prepared according to the procedure in Preparation Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When washing the hydroformylation reaction solution with a polymer aqueous solution, the concentration and amount of the polymer aqueous solution were changed from 0.5 wt% and 50 kg (0.2 times) in Example 1 to 0.1 wt% and 125 kg (0.5 times) in Comparative Example 1, and 0.3 wt% and 20 kg (0.08 times) in Comparative Example 2, respectively. Other treatment conditions and procedures remained consistent with those in Example 1.

[0063] Washing conditions of polymer aqueous solutions in Comparative Examples 3-4 The hydroformylation reaction solution was prepared according to the procedure in Preparation Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When washing the hydroformylation reaction solution with a polymer aqueous solution, the washing temperature and time were changed from 80°C and 60 min in Example 1 to 50°C and 180 min in Comparative Example 3, and 90°C and 20 min in Comparative Example 4, respectively. Other treatment conditions and steps were consistent with those in Example 1.

[0064] Comparative Examples 5-6: Tin Salt Solutions The hydroformylation reaction solution was prepared according to the procedure in Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When using tin salt solution to dissolve the polymer, the concentration and amount of tin salt solution were changed from 3 mol / L and 2.5 kg (10 times) in Example 1 to 0.5 mol / L and 3.75 kg (15 times) in Comparative Example 5, and 5 mol / L and 0.75 kg (3 times) in Comparative Example 6, respectively. Other processing conditions and steps remained the same as in Example 1.

[0065] Comparative Example 7: Wuxi Salt The hydroformylation reaction solution was prepared according to the procedure in Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When dissolving the polymer using a tin salt solution, the concentration and amount of the tin salt solution were changed from 3 mol / L and 2.5 kg (10 times) in Example 1 to 0 and 3.75 kg (15 times) in Comparative Example 7, i.e., 3.75 kg of deionized water was used for dissolution. Other treatment conditions and procedures remained the same as in Example 1.

[0066] Comparative Example 8: Extractant Dosage The hydroformylation reaction solution was prepared according to the procedure in Preparation Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When extracting the tin salt solution with an organic extractant, the amount of extractant was changed from 1 kg (0.4 times) in Example 1 to 0.25 kg (0.1 times) in Comparative Example 8. Other processing conditions and steps were consistent with those in Example 1.

[0067] Comparative Examples 9-10: Hydrochloric Acid Dosage The hydroformylation reaction solution was prepared according to the procedure in Example 3, and Rh in the reaction solution was recovered according to the procedure in Example 1. When washing the extractant solution with hydrochloric acid, the concentration and amount of hydrochloric acid were changed from 5 mol / L and 1.5 kg (1.5 times) in Example 1 to 2 mol / L and 2.5 kg (2.5 times) in Comparative Example 9, and 12 mol / L and 0.5 kg (0.5 times) in Comparative Example 10, respectively. Other treatment conditions and procedures remained consistent with those in Example 1.

[0068] The Rh powder extracted and recovered from the hydroformylation reaction solution in the above embodiments and comparative examples was weighed, and samples were processed according to the method in HJ 700-2014. The purity of Rh was detected using inductively coupled plasma mass spectrometry, and the recovery efficiency of Rh was calculated. The data from each embodiment and comparative example are summarized in the following table: Table 1. Rh recovery data for each embodiment and comparative example.

[0069] As can be seen from the data in Table 1, the present invention can achieve excellent rhodium recovery under different experimental conditions. The amount, purity, and total recovery rate of rhodium powder recovered in Examples 1-17 remained stable, with the highest recovery rate reaching 98.4% and the overall recovery rate consistently maintained above 97%; the highest purity of rhodium powder reached 98.4%. This indicates that the present invention has good repeatability within different process parameter ranges.

[0070] Comparative Examples 1 and 2, by varying the polymer concentration and dosage, resulted in rhodium recovery rates decreasing to 93.3% and 92.1%, respectively, indicating that insufficient polymer concentration or dosage hinders the complete transfer of rhodium. Comparative Examples 3 and 4, by varying the washing temperature and time with the polymer aqueous solution, significantly reduced rhodium recovery rates, demonstrating that excessively low washing temperatures or short washing times are detrimental to the effective capture of rhodium by the polymer. Comparative Examples 5 and 6, by varying the tin salt solution concentration and dosage, resulted in rhodium recovery rates decreasing to 83.0% and 88.1%, respectively. Comparative Example 7, omitting the tin salt solution, showed a rhodium recovery rate of only 60.1%, proving that the activation effect of SnCl2 has a significant impact on rhodium extraction, and that its concentration and dosage must be within an appropriate range. Comparative Example 8, by varying the dosage of the organic extractant, reduced the rhodium recovery rate to 78.5%, indicating that insufficient extractant prevents sufficient rhodium enrichment. Comparative Examples 9 and 10 changed the concentration and amount of hydrochloric acid, and the rhodium recovery rate decreased to 87.7% and 85.4%, respectively, indicating that too low a concentration or insufficient amount of hydrochloric acid will affect the back-extraction efficiency.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for recovering metallic rhodium from rhodium-containing organic materials, characterized in that, Includes the following steps: Rhodium-containing organic materials and polymer aqueous solutions are mixed and then washed and allowed to stand for separation to obtain a rhodium-containing polymer aqueous solution; the polymer in the polymer aqueous solution is poly(N-isopropylacrylamide-co-acrylic acid); the concentration of the polymer aqueous solution is 0.2~3wt%; the mass of the polymer aqueous solution is 0.1~0.5 times the mass of the rhodium-containing organic materials; the washing temperature is 60~90℃ and the time is 30~180min; The rhodium-containing polymer aqueous solution was heated and then filtered while hot to obtain a rhodium-containing polymer solid. The rhodium-containing polymer solid is dissolved in a tin salt solution, followed by extraction with an organic extractant to obtain a rhodium-containing organic phase; the concentration of the tin salt solution is 1-5 mol / L; the mass of the tin salt solution is 4-15 times the mass of the polymer; the mass of the organic extractant is 0.2-2 times the mass of the tin salt solution; the organic extractant is prepared from a quaternary ammonium salt and a fatty acid. The rhodium-containing organic phase is back-extracted with hydrochloric acid to obtain a rhodium-containing hydrochloric acid solution phase; the concentration of the hydrochloric acid is 3~12 mol / L; the total mass of the hydrochloric acid is 1~2.5 times the mass of the organic extractant.

2. The method according to claim 1, characterized in that, The rhodium-containing organic material is a reaction solution for hydroformylation; the Rh content in the rhodium-containing organic material is 10~800ppm.

3. The method according to claim 1, characterized in that, The mass fraction of acrylic acid in the poly(N-isopropylacrylamide-co-acrylic acid) is 5~25wt%.

4. The method according to claim 1, characterized in that, The temperature for static stratification is 10~20℃; the final temperature for heating is 50~90℃.

5. The method according to claim 1, characterized in that, The tin salt solution is a stannous chloride solution.

6. The method according to claim 1, characterized in that, The quaternary ammonium salt is methyltrioctylammonium oleate; the fatty acid is oleic acid.

7. The method according to claim 1, characterized in that, The hot filtration also yields an aqueous phase; the back-extraction also yields a recovered extractant phase; the aqueous phase and the recovered extractant phase are recycled.

8. The method according to claim 1, characterized in that, The extraction also yields a polymer-containing tin salt solution phase; the polymer-containing tin salt solution phase is heated and filtered while hot to obtain a recovered polymer and a recovered tin salt solution; the recovered polymer and the recovered tin salt solution are recycled.

9. The method according to claim 1, characterized in that, After obtaining the rhodium-containing hydrochloric acid solution phase, the process further includes mixing the rhodium-containing hydrochloric acid solution phase, adsorbent, and reducing agent for adsorption-reduction treatment, performing solid-liquid separation on the resulting treated liquid to obtain a rhodium-containing precipitate, and calcining the rhodium-containing precipitate to obtain metallic rhodium.

10. The method according to claim 9, characterized in that, The adsorbent is one or more of biochar and powdered activated carbon; the mass of the adsorbent is 0.5~2wt% of the mass of the hydrochloric acid solution phase. The reducing agent is one or more of sulfur dioxide, sodium bisulfite, formic acid, and hydrazine hydrate; The roasting temperature is 400~800℃ and the time is 60~180 min.

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