A method for recovering metal platinum from spent SAPO-11 molecular sieve isomerization hydrogenation catalyst

Abstract

The invention discloses a method for recovering metal platinum in a waste SAPO-11 molecular sieve isomerization hydrogenation catalyst. The method comprises the following three steps: pretreatment of the SAPO-11 molecular sieve isomerization hydrogenation catalyst, preparation of a leaching solution and refining of the metal platinum. The waste SAPO-11 molecular sieve isomerization catalyst is ground, roasted and wet-milled after sorting to remove impurities such as porcelain balls; wet-milling-leaching-replacement-refining is carried out in a NaOH-H2S04-NaClO3 medium to obtain sponge platinum or calcine to obtain platinum ingots; the method adopts an alkaline leaching process, can realize efficient separation and recovery of metal platinum in the SAPO-11 molecular sieve isomerization decondensation waste catalyst, has simple process, less pollution and high recovery rate of metal platinum.

Description

Technical Field

[0001] The invention relates to the technical field of waste catalyst recovery, and in particular to a method for recovering metal platinum in a waste SAPO-11 molecular sieve isomerization hydrogenation catalyst. Background Art

[0002] Biodiesel is an organic fuel processed from biomass resources. It has a very low sulfur content, so when it is burned, there will be very little emission of carbon dioxide and its sulfide. The raw material of biodiesel is biomass, and the main component of biomass is fatty acid ester, which is generally made by esterification of renewable oils such as rapeseed oil, soybean oil, recycled cooking oil, animal oil, palm oil, etc. with alcohol (methanol, ethanol). The cetane number and cold filter point are 10~15℃, and the fluidity is poor. In order to improve the cold filter point, precious metal platinum catalysts are used for isomerization hydrogenation reaction to reduce the cold filter point.

[0003] In the prior art, a precious metal platinum catalyst is a catalyst with SAPO-11 molecular sieve as the main carrier, and the platinum contained in the catalyst is a rare precious metal. The Chinese patent with publication number CN104263945A protects a method for recovering platinum group metals from waste catalysts. The invention discloses a method for recovering platinum group metals from waste catalysts. The Chinese patent with publication number CN103194606A discloses a method for enriching platinum group metals from alumina-based waste catalysts. In the existing public literature, the methods for recovering platinum group metals from alumina-supported platinum group metal catalysts are mostly based on wet processes, and the wet process has the problem of waste liquid volume.

[0004] In the existing technology, biodiesel is an organic fuel processed from biomass resources. It has a very low sulfur content, so the emission of carbon dioxide and its sulfide is very small when it is burned. Under the condition of a catalyst, the emission can be reduced by 70%. It does not contain aromatic alkanes that are harmful to the human body, and the harm to the environment and human body after combustion is very low. It is the best product to solve the energy crisis and replace diesel, and it is renewable. The cold filter point is generally around -20℃. It is completely possible to achieve low-temperature flow of diesel without adding any additives. It has a high content, a large cetane number, and better combustion performance than diesel.

[0005] The raw material of biodiesel is biomass, the main component of which is fatty acid esters, which are generally made by esterification of renewable oils such as rapeseed oil, soybean oil, recycled cooking oil, animal oil, palm oil, etc. with alcohol (methanol, ethanol). The cetane number and cold filter point are 10~15℃, and the fluidity is poor. In order to improve the cold filter point, precious metal platinum catalysts are used for isomerization hydrogenation reaction to reduce the cold filter point. Precious metal platinum catalysts are catalysts with SAPO-11 molecular sieve as the main carrier.

[0006] The precious metal platinum catalyst is a catalyst with SAPO-11 molecular sieve as the main carrier. It is used in the biomass hydrogenation reaction mainly based on palmitic acid oil to isomerize the raw material alkane, thereby reducing the cold filter point and the liquid yield reaching more than 97.5%. This catalyst adsorbs impurities and poisons in the oil during use on the device, resulting in permanent deactivation of the catalyst. The service life is generally 3-5 years. The deactivated catalyst is replaced from the device and becomes solid waste. Direct disposal has a great impact on the environment. At the same time, the platinum (Pt) contained in the catalyst is a rare precious metal, which is rarely distributed in nature and is expensive. It is widely used in various industrial production processes and has a high recycling value. The present invention comprehensively utilizes and recycles this part of the waste catalyst, which can not only save precious resources, but also avoid the impact on the environment, and has good economic and environmental benefits. The research on the recovery technology of metal platinum in the isomerization hydrogenation catalyst with molecular sieve as the carrier has important theoretical significance and engineering value.

[0007] SAPO-11 molecular sieve is a silicon-aluminum-phosphorus molecular sieve, a microporous crystal. It has excellent shape selectivity, acidity adjustability and wet-heat stability, and is used in hydrogenation, dehydrogenation, reforming, hydration and even cracking, alkylation, polymerization and other reactions. Small-particle SAPO-11 molecular sieve has a larger specific surface area, higher activity and stability, strong anti-poisoning performance, etc., and is an ideal carrier material for isomerization catalytic materials. Since SAPO-11 molecular sieve uses pseudo-boehmite alkaline silica sol as aluminum source and silicon source, and diethylamine as template agent. Therefore, the SAPO-11 molecular sieve of the present invention can obtain high-content silicon-aluminum powder through decomposition, separation and recovery, which is used in the production of polyaluminum chloride for sewage purification.

[0008] At present, there is no report on the invention patent of SAPO-11 molecular sieve loaded with platinum metal for isomerization decondensation. There are relatively few invention patents on alumina loaded with platinum metal for hydrogenation reaction. The typical ones are: Chinese patent CN113802005B A method for low-temperature smelting and recovery of platinum group metals in waste catalysts, discloses a method for low-temperature smelting and recovery of platinum group metals in waste catalysts. The invention is to first mix the waste catalyst, slag flux, collector, and reducing agent in a set proportion, smelt at a temperature of 1000-1200°C, react for a predetermined time, separate the solid and liquid, and obtain an alloy containing platinum group metals. The collector contains copper, tin, and nickel, and is prepared according to the loading range of Cu:Sn:Ni molar ratio = (10-70): (30-80): (0-10).

[0009] A Chinese patent with publication number CN104263945A discloses a method for recovering platinum group metals from waste catalysts. The invention discloses a method for recovering platinum group metals from waste catalysts, and the steps include: (1) calcination pretreatment: calcining the waste catalyst at a certain temperature to remove carbon and other organic matter on the surface; (2) room temperature soaking: firstly placing the pretreated waste catalyst in a soaking tank, adding a certain reducing solution for soaking; then adding an oxidizing solution for repeated soaking several times to obtain a solution containing platinum group metals; (3) metal replacement: adjusting the acidity of the solution containing platinum group metals, adding reducing metal replacement, solid-liquid separation, and obtaining crude platinum group metals; (4) platinum group metal refining: dissolving the crude platinum group metals, refining and purifying, and obtaining high-purity platinum group metals, with a platinum group metal recovery rate greater than 98% and a purity of 99.95%. The present invention can treat waste platinum group metal catalysts on alumina carriers in industries such as petroleum and fine chemicals, and has a simple process and is easy to implement industrially.

[0010] A Chinese patent with publication number CN103194606A discloses a method for enriching platinum group metals from alumina-based waste catalysts, comprising the following steps: A. primary incineration; B. crushing; C. pressurized crushing; D. filtration; and E. secondary incineration. The alumina dissolution rate is greater than 95%, and the recovery rate of platinum group metals is greater than 99%.

[0011] The methods for recovering platinum group metals from platinum group metal catalysts supported by alumina in existing public documents are mainly based on wet processes, which have the problem of large amounts of waste liquid. The reported high-temperature reduction smelting metal capture and recovery methods have problems such as inappropriate selection of smelting slag type, the use of metal oxides as collectors, the need for reduction smelting, high smelting temperatures, and low feasibility of industrial applications. Alumina has a low silicon content as a carrier, and is generally more suitable for acid leaching. In addition, the wet process will agglomerate during leaching, resulting in the need for secondary grinding later. The present invention is aimed at waste platinum-containing catalysts whose carriers are molecular sieves, and uses an alkaline method to recover platinum metal, thereby improving the recovery rate and metal purity. Summary of the invention

[0012] The purpose of the present invention is to provide a method for recovering metallic platinum in a waste SAPO-11 molecular sieve isomerization hydrogenation catalyst, which is aimed at the waste platinum-containing catalyst whose carrier is a molecular sieve, and uses an alkali method to recover the platinum metal, thereby improving the recovery rate and metal purity.

[0013] To achieve the above object, the technical solution of the present invention is: a method for recovering metal platinum from waste SAPO-11 molecular sieve isomerization hydrogenation catalyst, the technical key points of which are:

[0014] The method comprises the following steps:

[0015] S1: Pretreatment of SAPO-11 molecular sieve isomerization hydrogenation catalyst: grind the SAPO-11 molecular sieve platinum-containing waste catalyst, and then calcine it to remove moisture, carbon deposits and organic matter in the raw material; add abrasives to the calcined waste catalyst, and then seal it in a kettle for wet grinding;

[0016] S2: Preparation of leaching solution: The fine material pretreated in step S1 is dissolved in a salt solvent system, wherein the leaching solvent is one or two of NaOH-NaClO3, CH3COOH-NaClO3 and H2S04- NaClO3 acid-base combination leaching solvents, and the pretreated fine material is added with alkali and salt solvents, and the silicon-aluminum-phosphorus molecular sieve is converted into Al(OH)3, and the modified pseudo-boehmite is converted into a mixture of Al2(SO4)3 and AlCl3;

[0017] S3: Refining of metallic platinum: adding ammonium chloride for concentrated substitution to generate ammonium chloroplatinate, centrifugally filtering, and drying the concentrated and substituted wet ammonium chloroplatinate under normal pressure to generate finished ammonium chloroplatinate, which is further filtered and dried to become platinum, which can be made into platinum ingots by controlling the calcination temperature at 1200-1500°C as needed.

[0018] Preferably, the specific steps of pretreatment of the SAPO-11 molecular sieve isomerization hydrogenation catalyst are as follows:

[0019] S101: grinding the granular columnar SAPO-11 molecular sieve platinum-containing spent catalyst into coarse particles;

[0020] S102: calcining the catalyst ground in S101 for 2 to 6 hours, controlling the calcination temperature at 400 to 700° C. under normal pressure to remove moisture, carbon deposits and organic matter in the raw material;

[0021] S103: The part of the carbon that cannot be completely roasted in S102 forms carbon slag, and forms sediment in the sedimentation process;

[0022] S104: The treated waste catalyst is mixed with a grinding agent in a ratio of 5 to 9:1 and placed in a sealed kettle for wet grinding at a temperature of 150 to 300° C. When the temperature reaches 180° C., oxygen is blown into the kettle to promote oxidation.

[0023] Preferably, the steps for preparing the leachate are as follows:

[0024] S201: dissolving the fine material pretreated in step S1 with a salt solvent system, and selecting one or two of NaOH-NaClO3, CH3COOH-NaClO3 and H2S04- NaClO3 acid-base combination leaching solvents as leaching solvents;

[0025] S202: set the solid-liquid ratio to 1:4~8, the temperature to 80~115℃, the time to 0.5~2.5h, the oxygen ion concentration to 0.06mol / L, the ratio of leaching sodium hydroxide to concentrated sulfuric acid to 30%:50%, and the NaClO3 molar concentration to 0.02~0.08mol / L;

[0026] S203: The fine material pretreated by S202 is added into alkali and salt solvents, and 80% of the SAPO-11 silicon-aluminum-phosphorus molecular sieve is converted into Al(OH)3, and 20% of the modified pseudo-boehmite powder is converted into a mixture of Al2(SO4)3 and AlCl3.

[0027] Preferably, the specific steps of refining metallic platinum are as follows:

[0028] S301: adding ammonium chloride to the leachate obtained in S2 for concentration and replacement to generate ammonium chloroplatinate, and centrifugally filtering the filtrate to the concentration step for recycling;

[0029] S302: drying the wet ammonium chloroplatinate obtained by concentration and replacement in S301 at normal pressure and temperature of 90-120° C. for 3-7 hours to generate finished ammonium chloroplatinate;

[0030] S303: S302 is further filtered and dried to become platinum, which can be made into platinum ingots by controlling the calcination temperature at 1200-1500°C as needed.

[0031] Preferably, the calcination time after grinding in S1 is 1.2 hours, the calcination temperature is 550°C, the ratio of waste catalyst to grinding agent during wet grinding is 7:1, and the wet grinding temperature is 200°C.

[0032] Preferably, the salt solvent system in S2 uses a combination of NaOH-H2S04-NaClO3 acid and alkali as the leaching solvent, the leaching solid-liquid ratio is 1:5, the temperature is 95°C, the time is 1.5 hours, the oxygen ion concentration is 0.06 mol / L, and the leaching NaOH:H2SO4:NaClO3:H2O=20±5%:20±5%:15±5%:45±5%, wherein the molar concentration of NaClO3 is 0.05 mol / L.

[0033] Preferably, the metal platinum in S3 is concentrated and replaced at atmospheric pressure, at a temperature of 100° C., for 5 hours to obtain sponge platinum; and subsequently the calcination temperature is controlled to be 1300° C. to produce a finished platinum ingot.

[0034] Preferably, the abrasive in S104 is calcium hydrogen phosphate.

[0035] The advantages and beneficial effects of the present invention are as follows: the present invention provides an alkaline method for recovering platinum from SAPO-11 molecular sieves, wherein the SAPO-11 molecular sieve is mixed with modified pseudo-boehmite in a ratio of 4:1 as a catalyst carrier, and platinum metal is loaded to prepare the precious metal platinum in the isomerized degassing catalyst; since the SAPO-11 molecular sieve belongs to a silicon-aluminum-phosphorus molecular sieve, the silicon-aluminum ratio is 0.5, the silicon content is greater than 30%, and it belongs to a high-silicon carrier, if an acid method is used for leaching, the leachate will be emulsified and not easy to separate. Therefore, the alkaline method is used to firstly leach silicon and aluminum, and after the mixed solution is filtered, acid is added to dissolve the platinum. DETAILED DESCRIPTION

[0036] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0037] The present invention protects a method for recovering metal platinum from a waste SAPO-11 molecular sieve isomerization hydrogenation catalyst, specifically a method for recovering metal platinum from a SAPO-11 molecular sieve-loaded platinum biodiesel isomerization decondensation waste catalyst, which includes roasting and leaching, and enrichment of aluminum sulfate and platinum, solving the problem that the prior art method for recovering platinum group metals from alumina-supported platinum group metal catalysts is mainly based on wet processes, and there is a large amount of waste liquid; the existing high-temperature reduction smelting metal capture and recovery method has problems such as inappropriate selection of smelting slag type, using metal oxides as collectors, requiring reduction smelting, high smelting temperature, and low feasibility of industrial application. Alumina has a low silicon content as a carrier, and acid leaching is generally more suitable. And agglomeration occurs during leaching in the wet process, resulting in the need for secondary grinding later. The present invention is aimed at platinum-containing waste catalysts with molecular sieves as carriers, and uses an alkali method to recover platinum metal to improve the recovery rate and metal purity.

[0038] In the present application, the calcination and leaching method is to take the columnar SAPO-11 molecular sieve platinum-containing waste catalyst and carry out high-temperature calcination at normal pressure, control the calcination temperature at 400-700°C, and the calcination time is 2-6 hours to remove moisture, C and organic matter in the raw material.

[0039] Then, the calcined materials are added with sodium chloride, sodium chlorate, sodium hydroxide (30%), concentrated sulfuric acid (98%), and water in sequence, stirred at a temperature of 100-130°C and a pressure of 0.2-0.5MPa, and allowed to settle at normal pressure for 3-7 hours to allow them to fully dissolve, react, and dilute. Sodium chloride and sodium chlorate are used as reaction protective agents and do not participate in the reaction.

[0040] In the present application, the method for enriching aluminum sulfate and platinum is to electrically heat the aluminum sulfate and other impurity solutions to 70-100°C under vacuum for enrichment for 3-7 hours, cool the remaining materials to crystallize, control the crystallization temperature at 15°C, and then centrifuge and replace the filter residue to enrich aluminum sulfate. At the same time, ammonium chloride is added to the replacement kettle to generate ammonium chloroplatinate, which is centrifugally filtered and the filtrate is recycled to the concentration process.

[0041] The specific operation steps of the method for recovering metal platinum from the waste SAPO-11 molecular sieve isomerization hydrogenation catalyst are as follows:

[0042] S1: Pretreatment of SAPO-11 isomerized pour point depressant catalyst:

[0043] S101: grinding the granular columnar SAPO-11 molecular sieve platinum-containing spent catalyst into coarse particles;

[0044] S102: calcining the finely ground catalyst for 2 to 6 hours, controlling the calcination temperature to 400 to 700° C. under normal pressure to remove moisture and carbon deposits in the raw material;

[0045] S103: A small amount of carbon in S102 cannot be completely roasted to form carbon slag, and forms sediment in the sedimentation process;

[0046] S104: The above steps achieve the cleaning of the surface and pores of the waste catalyst, free of harmful components and impurities;

[0047] S105: Put the above-treated waste catalyst and grinding agent into a sealed kettle at a ratio of 5 to 9:1 for wet grinding; the wet grinding temperature is 150 to 300°C. When the temperature reaches a certain level, oxygen is blown into the kettle to promote oxidation;

[0048] S106: The abrasive described in S105 is a mixture of abrasives, dispersants and auxiliary materials, which can solve the lens corrosion phenomenon caused by grinding and is obtained through external purchase.

[0049] S2: Preparation of leachate:

[0050] S201: dissolving the fine material pretreated in step S1 with a salt-base system, and selecting one or two of NaOH-NaClO3, CH3COOH-NaClO3 and H2S04- NaClO3 acid-base combination leaching solvents as leaching solvents;

[0051] S202: Control the solid-liquid ratio to 1:4~8, the temperature to 80~115℃, the time to 0.5~2.5h, the oxygen ion concentration to 0.06mol / L, the ratio of leaching sodium hydroxide to concentrated sulfuric acid to 30%:50%, and the NaClO3 molar concentration to 0.02~0.08mol / L;

[0052] S203: The pretreated fine material is added into alkali and salt solvents, and 80% of the SAPO-11 silicon aluminum phosphorus molecular sieve is converted into Al(OH)3, and 20% of the modified pseudo-boehmite powder is converted into a mixture of Al2(SO4)3 and AlCl3.

[0053] S3: Refining of Platinum Metal:

[0054] S301: adding ammonium chloride to the mixture obtained in S203 for concentration and replacement to generate ammonium chloroplatinate, and centrifugally filtering the filtrate to the concentration step for recycling;

[0055] S302: Dry the wet ammonium chloroplatinate product after the concentration and replacement in S301 at normal pressure and temperature of 90-120°C for 3-7 hours to produce finished ammonium chloroplatinate. After further filtration and drying, it becomes platinum (sponge platinum), which can be made into platinum ingots by controlling the calcination temperature at 1200-1500°C as needed.

[0056] The specific steps of concentrating and precipitating platinum may be as follows:

[0057] The first step is to concentrate the platinum-containing solution by electric heating at 80-90°C at normal pressure to a platinum content of ≥30 g / L;

[0058] The second step is to add an excess of ammonium chloride to generate a crude ammonium chloroplatinate precipitate, wherein the amount of ammonium chloride added is 1.2-1.5 times the weight of the platinum in the solution;

[0059] The third step is to filter the solid-liquid mixture after platinum precipitation using a Buchner funnel;

[0060] Step 4: Dry the wet crude ammonium chloroplatinate at 80-105° C. for 1 hour to dry out the moisture, and then heat to 600° C. and calcine for 4-8 hours to obtain crude sponge platinum;

[0061] Step 5: Add hydrochloric acid and sodium chlorate to the crude sponge platinum at a temperature of 80-100°C for 2-6 hours, and filter after dissolving. The weight ratio of crude sponge platinum, hydrochloric acid, and sodium chlorate is 1:4:0.5;

[0062] Step 6: adding excess ammonium chloride to the dissolved solution to generate ammonium chloroplatinate precipitate, and filtering to obtain ammonium chloroplatinate;

[0063] Step 7: The wet ammonium chloroplatinate is dried by electric heating at 80-105° C. for 1 hour to dry out the moisture, and then the temperature is raised to 600° C. and calcined for 4-8 hours to obtain the finished sponge platinum.

[0064] Embodiment 1

[0065] First, a columnar SAPO-11 molecular sieve containing platinum waste catalyst is calcined at 400°C for 6 hours under normal pressure to remove moisture, C and organic matter from the raw material to obtain a calcined material;

[0066] Again, sodium hydroxide, sodium chlorate, and water were added to the reaction flask in sequence, wherein NaOH: NaClO3: H2O = 40%: 25%: 35%, wherein the molar concentration of NaClO3 was 0.05 mol / L, and the mixture was evenly mixed, placed in a 90°C water bath, 50 g of the above-mentioned calcined material was added, stirred, the pressure was controlled to 0.3 MPa, and the reaction was carried out at a constant temperature for 4 hours, and the filtrate and filter residue were obtained by hot filtration. The obtained filtrate was a mixed solution of aluminum hydroxide, aluminum chloride, and aluminum sulfate. According to the content of each component of the mixed solution, the dissolution rate of SAPO-11 molecular sieve was determined to be 95.5%, and the dissolution rate of modified pseudo-boehmite was 96%.

[0067] Next, the mixed solution was filtered and then H2SO4 (98%): NaClO3: H2O = 40%: 25%: 35%, where the molar concentration of NaClO3 was 0.05 mol / L.

[0068] The aluminum sulfate and other impurity solutions are then electrically heated to 70°C under vacuum for 4 hours, cooled to crystallize, and the crystallization temperature is controlled at 15°C. Centrifugal filtration is then performed, and the filter residue is replaced to enrich aluminum sulfate.

[0069] Finally, ammonium chloride was added to the displacement kettle for concentration to obtain ammonium chloroplatinate, wherein the amount of ammonium chloride added was: when the platinum content of the concentrated solution was 30 g / L, the amount of ammonium chloride added was 1.2-1.5 times the total amount of platinum in the solution. The ammonium chloroplatinate generated above was centrifuged and dried at 600°C to obtain sponge platinum. The platinum content of the sponge platinum was determined. The platinum yield was 97% and the purity was 99.95%.

[0070] Embodiment 2

[0071] First, columnar SAPO-11 molecular sieve platinum-containing waste catalyst is calcined at 450°C for 4.5 hours under normal pressure to remove moisture, C and organic matter from the raw material to obtain a calcined material;

[0072] Again, sodium hydroxide, sodium chlorate, and water were added to the reaction flask in sequence, wherein NaOH: NaClO3: H2O = 42%: 28%: 32%, wherein the molar concentration of NaClO3 was 0.04 mol / L, and the mixture was evenly mixed, placed in a 90°C water bath, 45 g of the above-mentioned calcined material was added, stirred, the pressure was controlled to 0.2 MPa, and the reaction was carried out at a constant temperature for 5 hours, and the filtrate and filter residue were obtained by hot filtration. The obtained filtrate was a mixed solution of aluminum hydroxide, aluminum chloride, and aluminum sulfate. According to the content of each component of the mixed solution, the dissolution rate of SAPO-11 molecular sieve was 94.5%, and the dissolution rate of modified pseudo-boehmite was 95%.

[0073] Next, the mixed solution was filtered and then H2SO4 (98%): NaClO3: H2O = 43%: 28%: 32%, where the molar concentration of NaClO3 was 0.04 mol / L.

[0074] The aluminum sulfate and other impurity solutions are then electrically heated to 80°C under vacuum for 4 hours, cooled for crystallization, and the crystallization temperature is controlled at 15°C. Centrifugal filtration is then performed, and the filter residue is replaced to enrich aluminum sulfate.

[0075] Finally, ammonium chloride was added to the displacement kettle for concentration to obtain ammonium chloroplatinate, wherein the amount of ammonium chloride added was: when the platinum content of the concentrated solution was 30 g / L, the amount of ammonium chloride added was 1.3 times the total amount of platinum in the solution. The ammonium chloroplatinate generated above was centrifuged and dried at 600°C to obtain sponge platinum. The platinum content of the sponge platinum was determined. The platinum yield was 98.7% and the purity was 99.94%.

[0076] Embodiment 3

[0077] First, a columnar SAPO-11 molecular sieve containing platinum waste catalyst is taken and calcined at 600°C for 4 hours under normal pressure to remove moisture, C and organic matter in the raw material to obtain a calcined material;

[0078] Again, sodium hydroxide, sodium chlorate, and water were added to the reaction flask in sequence, wherein NaOH: NaClO3: H2O = 45%: 30%: 38%, wherein the molar concentration of NaClO3 was 0.07 mol / L, and the mixture was evenly mixed, placed in a 90°C water bath, 50 g of the above-mentioned calcined material was added, stirred, the pressure was controlled to 0.3 MPa, and the reaction was carried out at a constant temperature for 3.5 hours, and the filtrate and filter residue were obtained by hot filtration. The obtained filtrate was a mixed solution of aluminum hydroxide, aluminum chloride, and aluminum sulfate. According to the content of each component of the mixed solution, the dissolution rate of SAPO-11 molecular sieve was determined to be 96.5%, and the dissolution rate of modified pseudo-boehmite was 97%.

[0079] Next, the mixed solution was filtered and then H2SO4 (98%): NaClO3: H2O = 45%: 30%: 38%, where the molar concentration of NaClO3 was 0.07 mol / L.

[0080] The aluminum sulfate and other impurity solutions are then electrically heated to 70°C under vacuum for 4.5 hours, cooled for crystallization, and the crystallization temperature is controlled at 15°C. Centrifugal filtration is then performed, and the filter residue is replaced to enrich aluminum sulfate.

[0081] Finally, ammonium chloride was added to the displacement kettle for concentration to obtain ammonium chloroplatinate, wherein the amount of ammonium chloride added was: when the platinum content of the concentrated solution was 30 g / L, the amount of ammonium chloride added was 1.5 times the total amount of platinum in the solution. The ammonium chloroplatinate generated above was centrifuged and dried at 600°C to obtain sponge platinum. The platinum content of the sponge platinum was determined. The platinum yield was 98% and the purity was 99.97%.

[0082] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for recovering metallic platinum from a spent SAPO-11 molecular sieve isomerization hydrogenation catalyst, characterized in that: The recovery method comprises the following steps: Firstly, a columnar SAPO-11 molecular sieve containing platinum waste catalyst is taken, and the calcination temperature is controlled at 400°C for 6 hours under normal pressure to remove moisture, C and organic matter in the raw material to obtain a calcined material; Again, sodium hydroxide, sodium chlorate and water were added to the reaction flask in sequence, wherein NaOH: NaClO3: H2O = 40%: 25%: 35%, wherein the molar concentration of NaClO3 was 0.05 mol / L, and the mixture was evenly mixed, and placed in a water bath at 90°C, and 50 g of the above-mentioned roasted material was added, stirred, and the pressure was controlled to be 0.3 MPa, and the reaction was carried out at a constant temperature for 4 hours, and the filtrate and filter residue were obtained by hot filtration. The obtained filtrate was a mixed solution of aluminum hydroxide, aluminum chloride and aluminum sulfate. According to the content of each component in the mixed solution, the dissolution rate of SAPO-11 molecular sieve was 95.5%, and the dissolution rate of modified pseudo-boehmite was 96%; Next, the mixed solution was filtered and then added with 98% H2SO4:NaClO3:H2O=40%:25%:35%, where the molar concentration of NaClO3 was 0.05mol / L; Then, the aluminum sulfate and other impurity solutions are electrically heated to 70°C under vacuum for 4 hours, cooled to crystallize, and the crystallization temperature is controlled at 15°C, and then centrifuged and filtered, and the filter residue is replaced to enrich aluminum sulfate; Finally, ammonium chloride was added to the displacement kettle for concentration to obtain ammonium chloroplatinate, wherein the amount of ammonium chloride added was: when the platinum content of the concentrated solution was 30 g / L, the amount of ammonium chloride added was 1.2-1.5 times the total amount of platinum in the solution. The ammonium chloroplatinate generated above was centrifuged and dried at 600°C to obtain sponge platinum. The platinum content of the sponge platinum was determined, with a platinum yield of 97% and a purity of 99.95%.

2. A method for recovering metallic platinum from a spent SAPO-11 molecular sieve isomerization hydrogenation catalyst, characterized in that: The recovery method comprises the following steps: Firstly, columnar SAPO-11 molecular sieve platinum-containing waste catalyst was taken, and the calcination temperature was controlled at 450°C for 4.5 hours under normal pressure to remove moisture, C and organic matter in the raw material to obtain a calcined material; Again, sodium hydroxide, sodium chlorate and water were added to the reaction flask in sequence, wherein NaOH: NaClO3: H2O = 42%: 28%: 32%, wherein the molar concentration of NaClO3 was 0.04 mol / L, and the mixture was evenly mixed, and placed in a 90°C water bath, and 45 g of the above-mentioned roasted material was added, stirred, and the pressure was controlled to be 0.2 MPa, and the reaction was carried out at a constant temperature for 5 hours, and the filtrate and filter residue were obtained by hot filtration. The obtained filtrate was a mixed solution of aluminum hydroxide, aluminum chloride and aluminum sulfate. According to the content of each component in the mixed solution, the dissolution rate of SAPO-11 molecular sieve was 94.5%, and the dissolution rate of modified pseudo-boehmite was 95%; Next, the mixed solution was filtered and then added with 98% H2SO4:NaClO3:H2O=43%:28%:32%, where the molar concentration of NaClO3 was 0.04 mol / L; Then, the aluminum sulfate and other impurity solutions are electrically heated to 80°C under vacuum for 4 hours, cooled to crystallize, and the crystallization temperature is controlled at 15°C, and then centrifuged and filtered, and the filter residue is replaced to enrich aluminum sulfate; Finally, ammonium chloride was added to the displacement kettle for concentration to obtain ammonium chloroplatinate, wherein the amount of ammonium chloride added was: when the platinum content of the concentrated solution was 30 g / L, the amount of ammonium chloride added was 1.3 times the total amount of platinum in the solution. The ammonium chloroplatinate generated above was centrifuged and dried at 600°C to obtain sponge platinum. The platinum content of the sponge platinum was determined, with a platinum yield of 98.7% and a purity of 99.94%.

3. A method for recovering metallic platinum from spent SAPO-11 molecular sieve isomerization hydrogenation catalyst, characterized in that: The recovery method comprises the following steps: Firstly, a columnar SAPO-11 molecular sieve containing platinum waste catalyst is taken, and the calcination temperature is controlled at 600°C for 4 hours under normal pressure to remove moisture, C and organic matter in the raw material to obtain a calcined material; Again, sodium hydroxide, sodium chlorate and water were added to the reaction flask in sequence, wherein NaOH: NaClO3: H2O = 45%: 30%: 38%, wherein the molar concentration of NaClO3 was 0.07 mol / L, and the mixture was evenly mixed, placed in a 90°C water bath, 50 g of the above-mentioned roasted material was added, stirred, the pressure was controlled to 0.3 MPa, and the reaction was carried out at a constant temperature for 3.5 hours, and the filtrate and filter residue were obtained by hot filtration. The obtained filtrate was a mixed solution of aluminum hydroxide, aluminum chloride and aluminum sulfate. According to the content of each component in the mixed solution, the dissolution rate of SAPO-11 molecular sieve was 96.5%, and the dissolution rate of modified pseudo-boehmite was 97%; Next, the mixed solution was filtered and then added with 98% H2SO4:NaClO3:H2O=45%:30%:38%, where the molar concentration of NaClO3 was 0.07mol / L; Then, the aluminum sulfate and other impurity solutions are electrically heated to 70°C under vacuum for 4.5 hours, cooled to crystallize, and the crystallization temperature is controlled at 15°C, and then centrifuged and filtered, and the filter residue is replaced to enrich aluminum sulfate; Finally, ammonium chloride was added to the displacement kettle for concentration to obtain ammonium chloroplatinate, wherein the amount of ammonium chloride added was: when the platinum content of the concentrated solution was 30 g / L, the amount of ammonium chloride added was 1.5 times the total amount of platinum in the solution. The ammonium chloroplatinate generated above was centrifuged and dried at 600°C to obtain sponge platinum. The platinum content of the sponge platinum was determined, with a platinum yield of 98% and a purity of 99.97%.