A method for recovering platinum and tin from spent reforming catalyst
Patent Information
- Application Number
- CN202610929073.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-25
- Publication Date
- 2026-10-30
AI Technical Summary
该工艺试剂消耗量小、耗水量低、工艺流程短、效率高，解决了传统工艺流程复杂、效率低的技术难题
本发明采用铂锡共浸工艺，工艺流程短，废水产生量少。所得酸性浸出液优先沉铂，避免回收锡过程造成金属铂损失，铂回收率高。利用有机磷/膦酸、中性磷、胺类或季铵盐类萃取剂共萃铁锡，实现铁锡与基底离子分离，尤其是采用中性磷、胺类或季铵盐类萃取时，无需调溶液酸度，酸碱消耗量小；弱酸性溶液反萃得到铂锡富集液，调控pH>3沉锡，获得氧化锡产品，实现战略金属元素铂锡的高效分离与回收。沉锡后的滤液加入氧化剂，将二价铁氧化为三价铁，会形成氢氧化铁沉淀，实现铁的回收，滤液可循环回用。铁锡共萃后的萃余液，通过调控pH>5，产生Al(OH)3沉淀，获得纯净三氧化铝产品。相比于传统工艺，本发明流程短，试剂消耗量少，耗水量低，废水量少，铂锡回收成本低，可同时实现铁和铝回收，具有显著的经济效应与环境效益。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of secondary metal resource recovery technology, specifically relating to a method for efficiently recovering platinum and tin strategic metals from spent reforming catalysts. This method enables short-process separation and recovery of platinum and tin, and is applicable to the resource-based treatment of spent reforming catalysts in the petrochemical industry. Background Technology
[0002] Platinum (Pt), a globally scarce strategic metal, holds an irreplaceable core position in modern industry. Specifically, platinum serves as a key active component in petroleum reforming catalysts, undertaking the primary catalytic function; tin (Sn), as an important co-catalyst, disperses and stabilizes platinum's electron modulation and acidity, inhibits hydrogenolysis and coking, enabling the catalyst to operate stably for long periods with high aromatic selectivity, low coking, and long-term stability under harsh reforming conditions. Platinum-tin catalysts are widely used in the core process of improving gasoline octane number, achieving efficient conversion in the petrochemical industry.
[0003] However, global platinum mineral resources are extremely unevenly distributed and scarce in total. Resources are mainly concentrated in a few regions such as South Africa and Russia, while tin resources are highly dependent on major mining areas such as Southeast Asia and South America. Furthermore, extracting platinum and tin from raw ore requires complex beneficiation, smelting, and refining processes, resulting in high production costs. At the same time, the amount of waste platinum and tin catalysts generated annually globally due to catalyst deactivation in reforming and alkane dehydrogenation units reaches thousands of tons, containing approximately 0.1%–0.3% platinum and 0.5%–1.5% tin, representing significant value. Currently, traditional platinum and tin recycling processes generally face multiple technical bottlenecks.
[0004] Many processes for platinum and tin separation and recovery employ a step-by-step approach due to their similar physicochemical properties and coordination behaviors. Common methods include high-temperature oxidation roasting, acid-base staged leaching, and oxidant-co-leaching. Some processes directly use strong acid systems to first dissolve the tin component, then leaching and enriching the platinum in the remaining solid phase. These traditional recovery processes not only require operation under high temperature, strong acid-base, and highly corrosive conditions, placing stringent demands on the corrosion resistance of reaction equipment materials, but also result in enormous overall reagent consumption, large quantities of highly acidic and hydrochloric wastewater and waste residue generated during production. Furthermore, the step-by-step leaching process is complex and lengthy, with cumbersome process connections, long material turnover cycles, and relatively high overall production costs.
[0005] Developing a method for recovering platinum and tin from spent reforming catalysts that is short in process, simple in method, and low in cost has significant industrial application value. Summary of the Invention
[0006] To address the shortcomings of existing technologies, this invention provides a method for efficiently recovering platinum and tin from spent reforming catalysts. This method involves co-leaching platinum and tin, preferential platinum precipitation, extraction to separate tin and iron, back-extraction to obtain a tin-iron enriched solution, and selective tin precipitation to yield ammonium chloroplatinate and tin oxide products. This process features low reagent consumption, low water consumption, a short process flow, and high efficiency, solving the technical problems of complex and inefficient traditional processes.
[0007] A method for recovering platinum and tin from spent reforming catalysts, characterized in that the active component of the spent reforming catalysts comprises platinum and tin, and the recovery steps include: (1) The waste reforming catalyst was leached at 50–150 °C in the presence of acid and oxidant; the solid-liquid ratio of the leaching system was 1:5–1:20. (2) Add liquid ammonia, ammonia water and / or ammonium salt to the oxidizing acid leaching solution to generate ammonium chloroplatinate precipitate, and separate it by centrifugation or filtration to obtain the ammonium chloroplatinate product; (3) Co-extract the iron and tin in the filtrate with organophosphorus / phosphonic acid, neutral phosphorus, amine or quaternary ammonium salt extractants, and back-extract to obtain an iron and tin-containing back-extract; the extraction ratio A / O is 5:1 to 1:5; (4) Add a reducing agent to the back-extraction solution, adjust the pH of the back-extraction solution to >3 with alkali to precipitate tin, and obtain tin oxide product after solid-liquid separation.
[0008] Further, the acid mentioned in step (1) is one or more of HCl, H2SO4, and HNO3, and the hydrogen ion concentration is 1 to 6 mol / L.
[0009] Further, the oxidant in step (1) is one or more of H2O2, Cl2, NaClO, NaClO2, NaClO3, KClO2, KClO3, HClO4, HClO, ClO2, HNO3, Na2O2, Na2S2O8, K2S2O8, and (NH4)2S2O8. The concentration of the solid and liquid oxidant is 0.05 mol / L to 10 mol / L, and the gaseous oxidant is a pure substance that is directly introduced.
[0010] Further, the method for determining the amount of liquid ammonia, ammonia water, or ammonium salt added in step (2) is to make the acidity of the solution between 0.1 and 2 mol / L. The purpose of adding liquid ammonia or ammonia water is firstly to adjust the acidity of the solution, but pH < 0.1, and secondly to provide ammonium ions so that ammonium chloroplatinate precipitate is formed. The ammonium salt is one or more of ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, and ammonium nitrate.
[0011] Further, the organophosphorus / phosphonic acid extractant in step (3) is one or more of the following: di(2-ethylhexyl) phosphate, di-sec-octyl phosphate, diisodecyl phosphate, 2-ethylhexyl phosphate-mono-2-ethylhexyl ester, octyl phosphate monooctyl ester, isooctyl phosphate monoisooctyl ester, di(2,4,4-trimethylpentyl)phosphonic acid, di(2-ethylhexyl)phosphonic acid, and (2,4,4-trimethylpentyl)(2-ethylhexyl)phosphonic acid. The extractant mass fraction is 5 vol % to 20 vol %.
[0012] Further, the neutral phosphorus extractant in step (3) is one or more of tributyl phosphate, trioctylphosphine oxide, dimethylheptyl methyl phosphate, dibutyl butyl phosphonate, and trialkylphosphine oxide, with a mass fraction of 5 vol% to 20 vol%.
[0013] Further, the amine extractant described in step (3) has the following structural formula: R1, R2, and R3 are aliphatic chains with 1 to 12 carbon atoms. R1, R2, and R3 can be the same or different. The sum of the carbon atoms in R1, R2, and R3 is less than 35. The extractant includes tri-n-octylamine, tri-isooctylamine, and 7-nonadecane primary amine. The mass fraction of the extractant is 5 vol % to 20 vol %.
[0014] Further, the quaternary ammonium salt extractant described in step (3) has the following structural formula: R4, R5, R6, and R7 are aliphatic chains with 1 to 12 carbon atoms. R4, R5, R6, and R7 can be the same or different. The sum of the carbon atoms of R4, R5, R6, and R7 is less than 35. Quaternary ammonium salt extractants include one or more of methyltrioctylammonium chloride and tridecylmethylammonium chloride. The mass fraction of quaternary ammonium salt extractants is 5 vol to 20 vol%.
[0015] Further, the reducing agent in step (4) is one or more of the following: iron powder, sodium sulfite, ammonium sulfite, sulfurous acid, sodium metabisulfite, sodium thiosulfate, sulfur dioxide, and stannous chloride.
[0016] Further, the alkali mentioned in step (4) is one or more of liquid ammonia, ammonia water, NaOH, KOH, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, calcium hydroxide, magnesium oxide, and magnesium hydroxide.
[0017] The beneficial effects that this invention can achieve are as follows: This invention employs a platinum-tin co-leaching process, which features a short process flow and low wastewater generation. The resulting acidic leachate preferentially precipitates platinum, avoiding platinum loss during tin recovery and achieving a high platinum recovery rate. Iron and tin are co-extracted using organophosphorus / phosphonic acid, neutral phosphorus, amines, or quaternary ammonium salt extractants to separate iron and tin from the substrate ions. Especially when using neutral phosphorus, amines, or quaternary ammonium salts for extraction, no solution acidity adjustment is required, resulting in low acid and alkali consumption. Back-extraction with a weakly acidic solution yields a platinum-tin enriched solution. Adjusting the pH to >3 precipitates tin oxide, achieving efficient separation and recovery of the strategic metal elements platinum and tin. An oxidant is added to the filtrate after tin precipitation to oxidize ferrous iron to ferric iron, forming ferric hydroxide precipitate, thus recovering iron. The filtrate can be recycled. The raffinate after iron-tin co-extraction, by adjusting the pH to >5, produces Al(OH)3 precipitate, yielding pure alumina. Compared to traditional processes, this invention has a shorter process, lower reagent consumption, lower water consumption, lower wastewater volume, lower platinum and tin recovery costs, and can simultaneously recover iron and aluminum, resulting in significant economic and environmental benefits. Detailed Implementation
[0018] The present invention will now be described in further detail with reference to specific embodiments. The provided embodiments are only used to explain the specific implementation of the present invention and do not constitute a limitation on the scope of protection of the present invention, nor do they limit the present invention in any way.
[0019] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.
[0020] Example 1
[0021] (1) Take 5 g of waste reforming catalyst and place it in a high-pressure reactor. Add 50 mL of 2 mol / L HCl solution containing 0.05 mol / L NaClO3. Stir and leach at 110°C for 4 hours. After the reaction is completed and cooled to room temperature, filter to obtain an acidic leachate.
[0022] (2) Take 10 mL of ammonia solution with a mass fraction of 1 wt% to 3 wt% and add it to the above acidic leachate. A yellow precipitate is produced. After filtration, the ammonia chloroplatinate product is obtained with a platinum recovery rate of 95.2%.
[0023] (3) The filtrate was mixed with 10 vol% P204 kerosene solution at a ratio of A / O = 1:2 by shaking. After extraction, the aqueous phase was separated. The organic phase was back-extracted with 2 mol / L H2SO4 to obtain an iron-tin back-extraction solution. An appropriate amount of iron powder was added to the solution to remove the Fe. 3+ Reduced to Fe 2+ The pH was adjusted to 4 by adding 8 wt%–10 wt% ammonia solution to obtain tin oxide precipitate. After filtration, 5 wt% H2O2 was added to the filtrate to remove Fe. 2+Re-oxidized to Fe 3+ Ferric hydroxide precipitate was obtained, with a tin recovery rate of 95.3% and an iron recovery rate of 94.5%.
[0024] Example 2
[0025] (1) Take 10 g of waste reforming catalyst, place it in a 500 mL three-necked flask, add 150 mL of 3 mol / L HCl solution, and purge with chlorine gas under reflux at 105 °C for 8 hours with stirring. After the reaction is completed and cooled to room temperature, filter to obtain an acidic leachate.
[0026] (2) 6 g of ammonium chloride was added to the obtained acidic leachate, a yellow precipitate was produced, and the product was obtained by filtration. The platinum recovery rate was 92.4%.
[0027] (3) The filtrate was mixed with 50 vol% TBP kerosene solution at a ratio of A / O = 1:1 by shaking. After extraction, the aqueous phase was separated. The organic phase was back-extracted with 0.1 mol / L HCl to obtain an iron-tin back-extracting solution. An appropriate amount of sodium sulfite was added to the solution to remove the Fe. 3+ Reduced to Fe 2+ The pH was adjusted to 4 by adding 5 wt% NaOH solution to obtain tin oxide precipitate. After filtration, 5 wt% NaClO2 was added to the filtrate to remove Fe. 2+ Re-oxidized to Fe 3+ Ferric hydroxide precipitate was obtained, with a tin recovery rate of 98.3% and an iron recovery rate of 92.6%.
Claims
1. A method for recovering platinum and tin from spent reforming catalysts, characterized in that, The active component of the spent reforming catalyst contains platinum and tin, and its recovery steps include: (1) The waste reforming catalyst was leached at 50-150 °C in the presence of acid and oxidant; the solid-liquid ratio of the leaching system was 1:5-1:20; (2) Add liquid ammonia, ammonia water and / or ammonium salt to the oxidizing acid leaching solution to generate ammonium chloroplatinate precipitate, and separate it by centrifugation or filtration to obtain the ammonium chloroplatinate product; (3) Co-extract the iron and tin in the filtrate with organophosphorus / phosphonic acid, neutral phosphorus, amine or quaternary ammonium salt extractants, and back-extract to obtain an iron and tin-containing back-extract; the extraction ratio A / O is 5:1 to 1:5; (4) Add a reducing agent to the back-extraction solution, adjust the pH of the back-extraction solution to >3 with alkali to precipitate tin, and obtain tin oxide product after solid-liquid separation.
2. The method for recovering platinum and tin from spent reforming catalysts according to claim 1, characterized in that, The acid mentioned in step (1) is one or more of HCl, H2SO4, and HNO3, with a hydrogen ion concentration of 1 to 6 mol / L.
3. The method for recovering platinum and tin from spent reforming catalysts according to claim 1, characterized in that, The oxidant in step (1) is one or more of H2O2, Cl2, NaClO, NaClO2, NaClO3, KClO2, KClO3, HClO4, HClO, ClO2, HNO3, Na2O2, Na2S2O8, K2S2O8, and (NH4)2S2O8. The concentration of the solid and liquid oxidant is 0.05 mol / L to 10 mol / L, and the gaseous oxidant is a pure substance that is directly introduced.
4. The method for recovering platinum and tin from spent reforming catalysts according to claim 1, characterized in that, The method for determining the amount of liquid ammonia, ammonia water, or ammonium salt added in step (2) is to ensure that the acidity of the liquid is between 0.1 and 2 mol / L, and that no precipitation is generated as liquid ammonia, ammonia water, or ammonium salt is added; the ammonium salt is one or more of ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, and ammonium nitrate.
5. The method for recovering platinum and tin from spent reforming catalysts according to claim 1, characterized in that, The organophosphorus / phosphonic acid extractant in step (3) is one or more of the following: di(2-ethylhexyl) phosphate, di-sec-octyl phosphate, diisodecyl phosphate, 2-ethylhexyl phosphate-mono-2-ethylhexyl ester, octyl phosphate monooctyl ester, isooctyl phosphate monoisooctyl ester, di(2,4,4-trimethylpentyl)phosphonic acid, di(2-ethylhexyl)phosphonic acid, and (2,4,4-trimethylpentyl)(2-ethylhexyl)phosphonic acid, with a mass fraction of 5 vol% to 30 vol%.
6. The method for recovering platinum and tin from spent reforming catalysts according to claim 1, characterized in that, The neutral phosphorus extractant in step (3) is one or more of the following: tributyl phosphate, trioctylphosphine oxide, dimethylheptyl methyl phosphate, dibutyl butyl phosphonate, and trialkylphosphine oxide, with a mass fraction of 5 vol % to 50 vol %.
7. The method for recovering platinum and tin from spent reforming catalysts according to claim 1, characterized in that, The amine extractant described in step (3) has the following structural formula: R1, R2, and R3 are aliphatic chains with 1 to 12 carbon atoms. R1, R2, and R3 can be the same or different. The sum of the carbon atoms of R1, R2, and R3 is less than 35. The extractant includes one or more of tri-n-octylamine, triisooctylamine, and 7-nonadecane primary amine. The mass fraction of the extractant is 5 vol % to 30 vol %.
8. The method for recovering platinum and tin from spent reforming catalysts according to claim 1, characterized in that, The quaternary ammonium salt extractant described in step (3) has the following structural formula: R4, R5, R6, and R7 are aliphatic chains with 1 to 12 carbon atoms. R4, R5, R6, and R7 can be the same or different. The sum of the carbon atoms of R4, R5, R6, and R7 is less than 35. Quaternary ammonium salt extractants include one or more of methyltrioctylammonium chloride and tridecylmethylammonium chloride. The mass fraction of quaternary ammonium salt extractants is 5 vol % to 30 vol %.
9. A method for recovering platinum and tin from spent reforming catalysts according to claim 1, characterized in that, The reducing agent mentioned in step (4) is one or more of the following: iron powder, sodium sulfite, ammonium sulfite, sulfurous acid, sodium metabisulfite, sodium thiosulfate, sulfur dioxide, and stannous chloride.
10. A method for recovering platinum and tin from spent reforming catalysts according to claim 1, characterized in that, The alkali mentioned in step (4) is one or more of the following: liquid ammonia, ammonia water, NaOH, KOH, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, calcium hydroxide, magnesium oxide, and magnesium hydroxide.