Method for recovering aluminum and enriching precious platinum group metal from cordierite type waste catalyst

Abstract

The invention discloses a method for recovering aluminum and enriching precious platinum group metals from a cordierite type waste catalyst. The method comprises the following steps: grinding, calcining and cooling the waste catalyst; uniformly mixing with sodium carbonate, calcium oxide and lithium fluoride, and calcining the mixed material at 880-1000 DEG C; the roasted material obtained through calcination is subjected to water leaching and filtering, and filtrate containing sodium aluminate and lithium hydroxide and leaching residues rich in platinum group metal are obtained; introducing CO2 gas into the filtrate, filtering to obtain a precipitation product I and filtrate I, and calcining the precipitation product I to obtain aluminum oxide; concentrating the filtrate I, continuously introducing CO2, and filtering to obtain filtrate II and lithium carbonate; according to the method, resource utilization of aluminum and efficient enrichment of platinum group metal are achieved at the same time, no toxic or harmful substance is discharged in the whole technological process, leaching residues and the filtrate are reasonably treated and utilized, and the method is environmentally friendly.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of platinum group metal resource recovery, and particularly relates to a method for recovering aluminum and enriching noble platinum group metals from cordierite type waste catalysts. BACKGROUND

[0002] Platinum group metals are mainly used for the preparation of catalysts in the field of high-temperature catalytic oxidation in the automobile, petroleum chemical industry and other industries. These catalysts will gradually lose their effectiveness during use and form waste catalysts. Therefore, the recovery of platinum group metals from waste catalysts is an important way to alleviate the contradiction between supply and demand of platinum group metals. The main component of cordierite is 2MgO·2Al2O3·5SiO2, which has good fire resistance and low thermal expansion rate, and is widely used as a carrier material for platinum group metal catalysts. Therefore, efficient recovery of cordierite type platinum group metals is a major concern in the field of platinum group metals.

[0003] At present, the method for recovering cordierite type platinum group metal catalyst mainly adopts a fire smelting enrichment method. In the plasma furnace electric arc furnace, a slag former, a collector, a reducing agent and the like are added for high-temperature smelting, the platinum group metals form an alloy with the metal collector, and the cordierite carrier is slagged with the slag former and the like, thereby realizing the recovery of platinum group metals. For example, Chinese patent CN 114990347A discloses a method for recovering platinum group metals from waste catalysts by fire smelting. Antimony and nickel are used as collectors to obtain an antimony-nickel alloy enriched with platinum group metals. Chinese patent CN 116445725A discloses a method for recovering platinum group metals from waste automobile exhaust catalysts by fire and platinum group metal powder. Hydrogen gas and magnesium vapor are introduced into the high-temperature melt to obtain an iron alloy, and the platinum group metal powder is obtained by atomization and acid dissolution. Chinese patent CN 111647751A discloses a method for enriching platinum group metals from automobile waste catalysts, which utilizes alkali roasting transformation to realize the removal of aluminum.

[0004] The content of aluminum oxide in cordierite is usually more than 40%, which meets the requirements of medium-grade bauxite, and has high recycling value. However, most of the current patents focus on the recovery of platinum group metals. In the traditional fire enrichment process, aluminum oxide enters the slag phase, and high-value utilization of aluminum resources cannot be realized. In addition, the higher the aluminum content in the smelting slag, the higher the melting point. High aluminum content requires a very high smelting temperature in the traditional fire enrichment process, which needs to be > 1500 ℃ to ensure efficient recovery of platinum group metals; or a high content of alkali needs to be added to reduce the melting point of the slag.

[0005] In summary, it is urgent to develop a pre-aluminum removal technology for cordierite type waste catalysts to realize the resource utilization of aluminum and reduce the cost of subsequent fire treatment. SUMMARY

[0006] To solve the above technical problems, the application provides a method for recovering aluminum and enriching precious platinum group metals from a cordierite type waste catalyst, which combines the structural characteristics of cordierite and proposes an "alkali transformation + water immersion" strategy for separating aluminum, thereby realizing the resource utilization of aluminum and the efficient enrichment of platinum group metals.

[0007] The technical scheme adopted by the application is as follows:

[0008] A method for recovering aluminum and enriching precious platinum group metals from a cordierite type waste catalyst, the method comprising the following steps:

[0009] 1) grinding, calcining and cooling the waste catalyst;

[0010] 2) uniformly mixing the material obtained in step 1 with sodium carbonate, calcium oxide and lithium fluoride, and then calcining the mixture at 880-1000 DEG C;

[0011] 3) water immersion and filtration of the calcined material obtained in step 2 to obtain a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals;

[0012] 4) passing CO2 gas into the filtrate containing sodium aluminate and lithium hydroxide obtained in step 3 for 10-30 min, filtering to obtain a precipitate product one and a filtrate one, and calcining the precipitate product one to obtain aluminum oxide;

[0013] 5) continuing to pass CO2 into the filtrate one after concentration, keeping at 90-95 DEG C for 10-30 min, filtering to obtain a filtrate two and lithium carbonate; the filtrate two is evaporated and crystallized to obtain sodium carbonate which is recycled to step 2.

[0014] In step 1, the powder particle size is 100-200 mesh.

[0015] In step 1, the calcination is carried out at 450-550 DEG C for 0.5-1.5 h.

[0016] In step 2, the total amount of sodium carbonate, calcium oxide and lithium fluoride added is 2-3.5:1 by mass ratio.

[0017] In step 2, the molar ratio among calcium oxide, lithium fluoride and sodium carbonate is (1-2):(1-4):(4-8).

[0018] In step 2, the calcination time is 60-120 min.

[0019] In step 3, the water immersion temperature is 50-90 DEG C, and the liquid-solid ratio of water immersion is (3-6):1.

[0020] In step 3), the platinum group metal is recovered from the leaching residue rich in platinum group metal by a fire smelting method.

[0021] In step 4), the pH of the filtrate is kept at 6.9-7.1.

[0022] In step 5), the pH of the filtrate 1 is kept at 10.4-12.1.

[0023] In the method for recovering aluminum and enriching precious platinum group metal from the cordierite type waste catalyst provided by the application, the waste catalyst is first ground into fine powder and then pre-treated by calcination to remove the residual organic matter on the surface; then mixed with sodium carbonate, calcium oxide and lithium fluoride and high-temperature calcination is carried out to convert the aluminum oxide in the cordierite into water-soluble sodium aluminate and convert the silicon dioxide in the cordierite into insoluble calcium silicate and calcium fluorosilicate, and selective separation of aluminum is realized by water immersion, and the addition of lithium fluoride can significantly reduce the temperature of the calcination transformation to realize low-temperature decomposition of the cordierite; finally, two-stage carbon dioxide is introduced into the separated solution to convert the sodium aluminate into aluminum hydroxide precipitate and lithium carbonate, and the aluminum hydroxide precipitate is prepared into aluminum oxide product by high-temperature calcination, and the residual sodium carbonate in the solution can be recovered by evaporation concentration method and recycled to the high-temperature calcination process in step 2).

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] (1) The alkali calcination transformation pretreatment technology using sodium carbonate, calcium oxide and lithium fluoride can realize low-temperature and high-efficiency decomposition of the cordierite carrier, open the package of the platinum group metal in the cordierite carrier and facilitate the subsequent recovery of the platinum group metal. The application innovatively proposes a mixed calcination system of soda ash, lime and lithium fluoride, uses the eutectic system formed by lithium fluoride and calcium oxide at a certain temperature to release high-activity fluoride ions, preferentially attacks Al2O3 and MgO in the carrier in the cordierite, makes the cordierite skeleton lose support and form a large number of structural defects, and at high temperature, lithium ions have a small radius and can form low-melting-point eutectics such as Li3AlF6 (melting point 580℃) with aluminum ions and fluoride ions in the carrier, and at high temperature, lithium ions can replace magnesium ions or aluminum ions in the cordierite lattice structure, causing distortion of the cordierite lattice, so that the cordierite can be efficiently decomposed at a lower temperature, thereby reducing the energy consumption of the alkali calcination transformation.

[0026] (2) The alkali calcination-water leaching technology can not only realize selective dissolution of aluminum and facilitate recycling of aluminum resources, but also realize recycling of sodium carbonate and lithium resources, thereby reducing the production cost of the calcination transformation.

[0027] (3) Efficient recovery of aluminum resources is realized, which is finally converted into high-value aluminum oxide product to realize recycling of aluminum; and the platinum group metal is enriched in the leaching residue, which greatly reduces the subsequent extraction difficulty.

[0028] (4) The sodium carbonate can be recycled back to the calcination process of step 2), reducing raw material consumption and fresh reagent procurement cost.

[0029] (5) The method realizes complete treatment of the coesite type waste catalyst, avoids environmental pollution and resource waste caused by random disposal, the entire process does not emit toxic and harmful substances, the leaching residue and the filtrate are reasonably disposed and utilized, the environmental burden is small, the material utilization rate is high, and the green production concept is met. DETAILED DESCRIPTION

[0030] The application will be described in detail below with reference to examples.

[0031] The various raw materials, reagents, instruments and equipment used in the application can be purchased on the market or can be prepared by existing methods.

[0032] The composition of the coesite type waste catalyst used in the examples and comparative examples of the present application is shown in the following Table 1:

[0033] Table 1 Composition of platinum group metals and main oxides in coesite type waste three-way catalyst (mass fraction)

[0034]

[0035] Example 1

[0036] A method for recovering aluminum and enriching precious platinum group metals from coesite type waste catalyst, comprising the following steps:

[0037] 1) Material preparation: The retired three-way catalyst is ball milled for 30 min to ensure that the particle size is less than 200 mesh, and then calcined at 500 ℃ in a muffle furnace for 1 h. After calcination, it is naturally cooled to room temperature to obtain fine retired three-way catalyst particles without organic matter;

[0038] 2) Alkali roasting: calcium oxide, lithium fluoride and sodium carbonate are mixed uniformly according to a molar ratio of 2:3:5 to obtain a transformation agent, and 250 g of the transformation agent is mixed with 100 g of the treated retired three-way catalyst. After mixing evenly, it is added to a graphite crucible; the muffle furnace is preheated to 500 ℃, and then the graphite crucible containing the material is quickly added to the muffle furnace, and then heated to 950 ℃ at a heating rate of 8 ℃ / min, and kept for 90 min. After heating is completed, the graphite crucible is taken out and naturally cooled to room temperature to obtain the roasting and transformation of the matured material;

[0039] 3) The matured material is ground into powder, water leaching is carried out at a liquid-solid ratio of 4:1 and a leaching temperature of 75℃ for 1h, filtration is carried out, a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals are obtained, and a fire smelting method is used to recover platinum group metals from the leaching residue rich in platinum group metals;

[0040] 4) CO2 is introduced into the filtrate containing sodium aluminate and lithium hydroxide to control the pH of the filtrate to be between 6.9-9.1 and keep for 20min, after filtration, a precipitate product one and a filtrate one are obtained, then the precipitate product one is placed in a muffle furnace and calcined at 1200℃ for 1h, finally, aluminum oxide powder can be obtained;

[0041] 5) After the filtrate one is concentrated, CO2 is continuously introduced to control the pH to be between 10.4-12.1, the solution temperature is kept to be greater than 90℃, the reaction time is 30min, after the reaction, filtration is carried out, a lithium carbonate product and a filtrate two are obtained, and the filtrate two is evaporated and crystallized to obtain sodium carbonate.

[0042] Example 2

[0043] A method for recovering aluminum and enriching noble platinum group metals from a coesite type waste catalyst, comprising the following steps:

[0044] 1) Material preparation: The retired ternary catalyst is ball milled for 30 min to ensure that the particle size is less than 200 mesh, and then calcined in a muffle furnace at 500℃ for 1h, and then naturally cooled to room temperature to obtain fine retired ternary catalyst particles without organic matter;

[0045] 2) Alkali roasting: calcium oxide, lithium fluoride and sodium carbonate are mixed uniformly according to a molar ratio of 1.5:2.5:6 to obtain a transformation agent, and 250g of the transformation agent is mixed with 100g of the treated retired ternary catalyst, and then added to a graphite crucible after uniform mixing; the muffle furnace is preheated to 500℃, and then the graphite crucible containing the material is quickly added to the muffle furnace, and then heated to 950℃ at a heating rate of 8℃ / min, and kept for 90min. After heating is completed, the graphite crucible is taken out and naturally cooled to room temperature to obtain the roasting transformed matured material;

[0046] 3) The matured material is ground into powder, water leaching is carried out at a liquid-solid ratio of 4:1 and a leaching temperature of 75℃ for 1h, filtration is carried out, a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals are obtained, and a fire smelting method is used to recover platinum group metals from the leaching residue rich in platinum group metals;

[0047] 4) CO2 is introduced into the filtrate containing sodium aluminate and lithium hydroxide to control the pH to be between 6.9-9.1 and maintain for 20 min, after filtration, precipitate product one and filtrate one are obtained, then the precipitate product one is placed in a muffle furnace and calcined at 1200 ℃ for 1 h, finally, aluminum oxide powder can be obtained;

[0048] 5) After the filtrate one is concentrated, CO2 is continuously introduced, the pH is controlled to be between 10.4-12.1, the solution temperature is maintained to be greater than 90 ℃, the reaction time is 30 min, after the reaction, filtration is performed, lithium carbonate product and filtrate two are obtained, and sodium carbonate is obtained by evaporation and crystallization of the filtrate two.

[0049] Example 3

[0050] A method for recovering aluminum and enriching noble platinum group metals from a coesite type waste catalyst, comprising the following steps:

[0051] 1) Material preparation: the retired ternary catalyst is ball milled for 30 min to ensure that the particle size is less than 200 mesh, then calcined at 500 ℃ for 1 h in a muffle furnace, and naturally cooled to room temperature after calcination to obtain fine retired ternary catalyst particles without organic matter;

[0052] 2) Alkali roasting: calcium oxide, lithium fluoride and sodium carbonate are mixed uniformly according to a molar ratio of 1.5:2.5:6 to obtain a transformation agent, and 350 g of the transformation agent is mixed with 100 g of the treated retired ternary catalyst, then uniformly mixed and added to a graphite crucible; the muffle furnace is preheated to 500 ℃, then the graphite crucible containing the material is quickly added to the muffle furnace, then heated to 950 ℃ at a heating rate of 8 ℃ / min, and kept for 90 min. After the heating is completed, the graphite crucible is taken out and naturally cooled to room temperature to obtain the roasting and transformation of the matured material;

[0053] 3) The matured material is ground into powder, water leaching is performed at a liquid-solid ratio of 4:1 and a leaching temperature of 75 ℃ for 1 h, filtration is performed, and a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals are obtained, and the platinum group metals are recovered from the leaching residue rich in platinum group metals by a pyrometallurgical method;

[0054] 4) CO2 is introduced into the filtrate containing sodium aluminate and lithium hydroxide to control the pH to be between 6.9-9.1 and maintain for 20 min, after filtration, precipitate product one and filtrate one are obtained, then the precipitate product one is placed in a muffle furnace and calcined at 1200 ℃ for 1 h, finally, aluminum oxide powder can be obtained;

[0055] 5) After the filtrate one is concentrated, CO2 is continuously introduced, the pH is controlled to be between 10.4-12.1, the solution temperature is maintained to be greater than 90 ℃, the reaction time is 30 min, after the reaction, filtration is performed, lithium carbonate product and filtrate two are obtained, and sodium carbonate is obtained by evaporation and crystallization of the filtrate two.

[0056] Example 4

[0057] A method for recovering aluminum and enriching noble platinum group metals from a coesite type waste catalyst, comprising the following steps:

[0058] 1) Material preparation: the retired ternary catalyst is ball milled for 30 min to ensure that the particle size is less than 100 mesh, and then calcined at 500 ℃ in a muffle furnace for 1 h, and then naturally cooled to room temperature to obtain fine retired ternary catalyst particles without organic matter;

[0059] 2) Alkali roasting: calcium oxide, lithium fluoride and sodium carbonate are mixed uniformly according to a molar ratio of 1.5:2.5:6 to obtain a conversion agent, and 250 g of the conversion agent is mixed with 100 g of the treated retired ternary catalyst, and then uniformly mixed and added to a graphite crucible; the muffle furnace is preheated to 500 ℃, and then the graphite crucible containing the material is quickly added to the muffle furnace, and then heated to 980 ℃ at a heating rate of 8 ℃ / min, and kept for 90 min. After heating is completed, the graphite crucible is taken out and naturally cooled to room temperature to obtain a roasting conversion of the cured material;

[0060] 3) The cured material is ground into powder, water leaching is carried out at a liquid-solid ratio of 4:1 and a leaching temperature of 75 ℃ for 1 h, and filtration is carried out to obtain a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals, and a method of fire smelting is used to recover platinum group metals from the leaching residue rich in platinum group metals;

[0061] 4) CO2 is introduced into the filtrate containing sodium aluminate and lithium hydroxide to control the pH to be between 6.9-9.1 and maintain for 20 min, and after filtration, a precipitate product I and a filtrate I are obtained, and then the precipitate product I is placed in a muffle furnace and calcined at 1200 ℃ for 1 h, and finally aluminum oxide powder is obtained;

[0062] 5) After the filtrate I is concentrated, CO2 is continuously introduced to control the pH to be between 10.4-12.1, the solution temperature is greater than 90 ℃, the reaction time is 30 min, after reaction, filtration is carried out to obtain a lithium carbonate product and a filtrate II, and the filtrate II is evaporated and crystallized to obtain sodium carbonate.

[0063] Comparative Example 1

[0064] A method for recovering aluminum and enriching noble platinum group metals from a coesite type waste catalyst, comprising the following steps:

[0065] 1) Material preparation: the retired ternary catalyst is ball milled for 30 min to ensure that the particle size is less than 200 mesh, and then calcined at 500 ℃ in a muffle furnace for 1 h, and then naturally cooled to room temperature to obtain fine retired ternary catalyst particles without organic matter;

[0066] 2) Base roasting: mix calcium oxide, lithium fluoride and sodium carbonate uniformly according to a molar ratio of 1.5:2.5:1 to obtain a transformation agent, and take 250 g of the transformation agent and mix with 100 g of the treated retired ternary catalyst, then add to a graphite crucible after uniform mixing; preheat the muffle furnace to 500 ℃, then quickly add the graphite crucible containing the material to the muffle furnace, then heat to 950 ℃ at a heating rate of 8 ℃ / min, and keep for 90 min. After heating is completed, take out the graphite crucible and naturally cool to room temperature to obtain the roasted and transformed matured material;

[0067] 3) Grind the matured material into powder, water leach for 1 h at a liquid-solid ratio of 4:1 and a leaching temperature of 75 ℃, filter to obtain a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals, and recover platinum group metals from the leaching residue rich in platinum group metals by a pyrometallurgical method;

[0068] 4) Pass CO2 into the filtrate containing sodium aluminate and lithium hydroxide to control the pH to be between 6.9-9.1 and keep for 20 min, filter to obtain a precipitate product 1 and a filtrate 1, then place the precipitate product 1 in a muffle furnace and calcine at 1200 ℃ for 1 h, and finally obtain aluminum oxide powder;

[0069] 5) Continue to pass CO2 into the filtrate 1 after concentration, control the pH to be between 10.4-12.1, keep the solution temperature greater than 90 ℃, and react for 30 min, then filter after reaction to obtain a lithium carbonate product and a filtrate 2, and evaporate and crystallize the filtrate 2 to obtain sodium carbonate.

[0070] Comparative Example 2

[0071] A method for recovering aluminum and enriching precious platinum group metals from a coesite type waste catalyst, comprising the following steps:

[0072] 1) Material preparation: ball mill the retired ternary catalyst for 30 min to ensure that the particle size is less than 200 mesh, then calcine in a muffle furnace at 500 ℃ for 1 h, and naturally cool to room temperature after calcination to obtain fine retired ternary catalyst particles without organic matter;

[0073] 2) Base roasting: mix calcium oxide, lithium fluoride and sodium carbonate uniformly according to a molar ratio of 1.5:0.5:6 to obtain a transformation agent, and take 250 g of the transformation agent and mix with 100 g of the treated retired ternary catalyst, then add to a graphite crucible after uniform mixing; preheat the muffle furnace to 500 ℃, then quickly add the graphite crucible containing the material to the muffle furnace, then heat to 950 ℃ at a heating rate of 8 ℃ / min, and keep for 90 min. After heating is completed, take out the graphite crucible and naturally cool to room temperature to obtain the roasted and transformed matured material;

[0074] 3) The matured material is ground into powder, water leaching is carried out at a liquid-solid ratio of 4:1 and a leaching temperature of 75°C for 1 h, filtration is carried out, a filtrate containing sodium aluminate and lithium hydroxide and a platinum group metal-rich leaching residue are obtained, and a fire smelting method is used to recover platinum group metals from the platinum group metal-rich leaching residue;

[0075] 4) CO2 is introduced into the filtrate containing sodium aluminate and lithium hydroxide to control the pH to be between 6.9-9.1 and maintain for 20 min, after filtration, a precipitate product 1 and a filtrate 1 are obtained, then the precipitate product 1 is placed in a muffle furnace and calcined at 1200°C for 1 h, and finally, aluminum oxide powder is obtained;

[0076] 5) After the filtrate 1 is concentrated, CO2 is continuously introduced to control the pH to be between 10.4-12.1, the solution temperature is maintained to be greater than 90°C, the reaction time is 30 min, after the reaction, filtration is carried out, lithium carbonate product and filtrate 2 are obtained, and the filtrate 2 is evaporated and crystallized to obtain sodium carbonate.

[0077] Comparative Example 3

[0078] A method for recovering aluminum and enriching precious platinum group metals from a coesite type waste catalyst, comprising the following steps:

[0079] 1) Material preparation: The retired ternary catalyst is ball milled for 30 min to ensure that the particle size is less than 200 mesh, and then calcined in a muffle furnace at 500°C for 1 h, and then naturally cooled to room temperature to obtain fine retired ternary catalyst particles without organic matter;

[0080] 2) Alkali roasting: calcium oxide, lithium fluoride and sodium carbonate are mixed uniformly according to a molar ratio of 0.5:2.5:6 to obtain a transformation agent, and 250 g of the transformation agent is mixed with 100 g of the treated retired ternary catalyst, and then the mixture is added to a graphite crucible; the muffle furnace is preheated to 500°C, and then the graphite crucible containing the material is quickly added to the muffle furnace, and then heated to 950°C at a heating rate of 8°C / min, and kept for 90 min. After heating is completed, the graphite crucible is taken out and naturally cooled to room temperature to obtain the roasting transformed matured material;

[0081] 3) The matured material is ground into powder, water leaching is carried out at a liquid-solid ratio of 4:1 and a leaching temperature of 75°C for 1 h, filtration is carried out, a filtrate containing sodium aluminate and lithium hydroxide and a platinum group metal-rich leaching residue are obtained, and a fire smelting method is used to recover platinum group metals from the platinum group metal-rich leaching residue;

[0082] 4) CO2 is introduced into the filtrate containing sodium aluminate and lithium hydroxide to control the pH to be between 6.9-9.1 and maintain for 20 min, after filtration, precipitate product one and filtrate one are obtained, then the precipitate product one is placed in a muffle furnace and calcined at 1200 ℃ for 1 h, finally, aluminum oxide powder can be obtained;

[0083] 5) After the filtrate one is concentrated, CO2 is continuously introduced, the pH is controlled to be between 10.4-12.1, the solution temperature is maintained to be greater than 90 ℃, the reaction time is 30 min, after the reaction, filtration is performed, lithium carbonate product and filtrate two are obtained, and sodium carbonate is obtained by evaporation and crystallization of the filtrate two.

[0084] Comparative Example 4

[0085] A method for recovering aluminum and enriching noble platinum group metals from a coesite type waste catalyst, comprising the following steps:

[0086] 1) Material preparation: the retired ternary catalyst is ball milled for 30 min to ensure that the particle size is less than 200 mesh, then calcined at 500 ℃ for 1 h in a muffle furnace, and naturally cooled to room temperature after calcination to obtain fine retired ternary catalyst particles without organic matter;

[0087] 2) Alkali roasting: calcium oxide, lithium fluoride and sodium carbonate are mixed uniformly according to a molar ratio of 1.5:2.5:6 to obtain a transformation agent, and 100 g of the transformation agent is mixed with 100 g of the treated retired ternary catalyst, then the mixture is added to a graphite crucible; the muffle furnace is preheated to 500 ℃, then the graphite crucible containing the material is quickly added to the muffle furnace, then heated to 950 ℃ at a heating rate of 8 ℃ / min, and kept for 90 min. After the heating is completed, the graphite crucible is taken out and naturally cooled to room temperature to obtain the roasting and transformation of the matured material;

[0088] 3) The matured material is ground into powder, water leaching is performed at a liquid-solid ratio of 4:1 and a leaching temperature of 75 ℃ for 1 h, filtration is performed, and a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals are obtained, and the platinum group metals are recovered from the leaching residue rich in platinum group metals by a pyrometallurgical method;

[0089] 4) CO2 is introduced into the filtrate containing sodium aluminate and lithium hydroxide to control the pH to be between 6.9-9.1 and maintain for 20 min, after filtration, precipitate product one and filtrate one are obtained, then the precipitate product one is placed in a muffle furnace and calcined at 1200 ℃ for 1 h, finally, aluminum oxide powder can be obtained;

[0090] 5) After the filtrate one is concentrated, CO2 is continuously introduced, the pH is controlled to be between 10.4-12.1, the solution temperature is maintained to be greater than 90 ℃, the reaction time is 30 min, after the reaction, filtration is performed, lithium carbonate product and filtrate two are obtained, and sodium carbonate is obtained by evaporation and crystallization of the filtrate two.

[0091] Comparative Example 5

[0092] A method for recovering aluminum and enriching noble platinum group metals from a coesite type waste catalyst, comprising the following steps:

[0093] 1) Material preparation: The retired ternary catalyst is ball milled for 30 min to ensure that the particle size is less than 200 mesh, and then calcined at 500 ℃ in a muffle furnace for 1 h. After calcination, it is naturally cooled to room temperature to obtain fine retired ternary catalyst particles without organic matter;

[0094] 2) Alkali roasting: Mix calcium oxide, lithium fluoride and sodium carbonate in a molar ratio of 1.5:2.5:6 to obtain a conversion agent, and mix 250 g of the conversion agent with 100 g of the treated retired ternary catalyst. After mixing evenly, it is added to a graphite crucible; preheat the muffle furnace to 500 ℃, then quickly add the graphite crucible containing the material to the muffle furnace, then heat to 850 ℃ at a heating rate of 8 ℃ / min, and keep for 90 min. After heating is completed, the graphite crucible is taken out and naturally cooled to room temperature to obtain the roasting and curing of the converted material;

[0095] 3) The roasting and curing material obtained by high temperature roasting is ground into powder, and water leaching is carried out at a liquid-solid ratio of 4:1 and a leaching temperature of 75 ℃ for 1 h, and filtration is carried out to obtain a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals, and platinum group metals are recovered from the leaching residue rich in platinum group metals by a pyrometallurgical method;

[0096] 4) CO2 is introduced into the filtrate containing sodium aluminate and lithium hydroxide to control the pH to be between 6.9-9.1 and maintain for 20 min, and after filtration, a precipitate product I and a filtrate I are obtained, then the precipitate product I is placed in a muffle furnace and calcined at 1200 ℃ for 1 h, and finally aluminum oxide powder is obtained;

[0097] 5) After the filtrate I is concentrated, CO2 is continuously introduced to control the pH to be between 10.4-12.1, the solution temperature is greater than 90 ℃, the reaction time is 30 min, after reaction, filtration is carried out to obtain lithium carbonate product and filtrate II, and the filtrate II is evaporated and crystallized to obtain sodium carbonate.

[0098] Comparative Example 6

[0099] A method for recovering aluminum and enriching noble platinum group metals from a coesite type waste catalyst, comprising the following steps:

[0100] 1) Material preparation: The retired ternary catalyst is ball milled for 30 min to ensure that the particle size is less than 100 mesh, and then calcined at 500 ℃ in a muffle furnace for 1 h. After calcination, it is naturally cooled to room temperature to obtain fine retired ternary catalyst particles without organic matter;

[0101] 2) Base roasting: 250 g of the transformation agent is mixed with 100 g of the treated retired three-way catalyst, and then the mixture is uniformly mixed and added to a graphite crucible. The muffle furnace is preheated to 500°C, and then the graphite crucible containing the material is quickly added to the muffle furnace, and then heated to 980°C at a heating rate of 8°C / min, and then kept for 45 min. After the heating is completed, the graphite crucible is taken out and naturally cooled to room temperature to obtain the roasting and transformation of the matured material;

[0102] 3) The matured material is ground into powder, and then water leaching is carried out at a liquid-solid ratio of 4:1 and a leaching temperature of 75°C for 1 h, and then filtration is carried out to obtain a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals, and a fire smelting method is used to recover platinum group metals from the leaching residue rich in platinum group metals;

[0103] 4) CO2 is introduced into the filtrate containing sodium aluminate and lithium hydroxide to control the pH to be between 6.9-9.1 and maintain for 20 min, and then the precipitate product I and the filtrate I are obtained after filtration, and then the precipitate product I is placed in a muffle furnace and calcined at 1200°C for 1 h, and finally the aluminum oxide powder is obtained;

[0104] 5) The filtrate I is concentrated and CO2 is continuously introduced to control the pH to be between 10.4-12.1, the solution temperature is greater than 90°C, the reaction time is 30 min, and then filtration is carried out after the reaction to obtain a lithium carbonate product and a filtrate II, and the filtrate II is evaporated and crystallized to obtain sodium carbonate.

[0105] Comparative Example 7

[0106] The same as Example 4, except that no lithium fluoride is used in step 2), and the molar ratio of calcium oxide and sodium carbonate is controlled to be 1.5:6.

[0107] Comparative Example 8

[0108] The same as Example 4, except that the lithium fluoride in step 2) is replaced by calcium fluoride.

[0109] Test Example

[0110] The reaction completed products and solutions of Examples 1-9 and Comparative Examples 1-2 are detected, and the detection results are shown in Table 2.

[0111] Table 2

[0112]

[0113] According to the above detection results, it can be seen that:

[0114] Compared with Example 1, the addition amount of calcium oxide and lithium fluoride in the transformation agent in Example 2 is relatively small, which causes a slight decrease in the aluminum recovery rate, but the yield of platinum group metals is improved to a certain extent. This is because the excessive addition of lithium fluoride in Example 1 causes the dissolution loss of platinum group metals in cordierite. However, the yield of platinum group metals in both Example 1 and Example 2 is more than 98%, and the recovery rate of aluminum is more than 93%, which has good aluminum recovery and platinum group metal enrichment effects.

[0115] Compared with Example 2, excessive transformation agent is added in Example 3, which causes an increase in the melt during the calcination process and also causes a certain loss of platinum group metals. However, the yield of platinum group metals in Example 3 can also be maintained at more than 98%, and the recovery rate of aluminum can also be maintained at more than 94%, which also has good aluminum recovery and platinum group metal enrichment effects.

[0116] Compared with Example 2, the particle size of the catalyst after ball milling in Step 1) in Example 4 is relatively large. Compared with Example 2, the recovery rate of aluminum in Example 4 is lower, and the platinum group metal enrichment multiple is also lower. However, the yield of platinum group metals in Example 4 can also be maintained at more than 98%, and the recovery rate of aluminum can be maintained at more than 85%, which also has good aluminum recovery and platinum group metal enrichment effects.

[0117] Compared with Example 2, the addition amount of sodium carbonate in the transformation agent in Comparative Example 1 is low, and the transformation effect of aluminum is not as obvious as that in Example 2. This is because the small amount of sodium carbonate cannot ensure the opening of the Si-Al-Mg structure in cordierite, resulting in a significant decrease in the recovery rate of aluminum.

[0118] Compared with Example 2, less lithium fluoride is added in the transformation agent in Comparative Example 2, and the content of fluorine and lithium in the melt system is low, which causes the reactant concentration to be insufficient when F corrodes cordierite.

[0119] Compared with Example 2, less calcium oxide is added in the transformation agent in Comparative Example 3. During the calcination reaction, sodium carbonate reacts with silicon dioxide in cordierite to form sodium silicate. The appropriate amount of calcium oxide can form insoluble calcium silicate with sodium silicate, reducing the competition between silicon and lithium, so that lithium focuses on destroying the Al-O bond.

[0120] Compared with Example 2, the amount of transformation agent is reduced in Comparative Example 4, which causes the reaction to be incomplete due to the lack of lithium, fluorine, calcium, Na2O, and other reactants in the melt.

[0121] Compared with Example 2, a lower calcination temperature is used in Step 2) in Comparative Example 5. During the calcination process, the viscosity of the melt increases, and the reaction rate decreases or even does not react.

[0122] Compared with Example 2, the baking time in step 2) of Comparative Example 6 is reduced, which can cause insufficient erosion time of fluorine, lithium and the like on the cordierite carrier in the trans-formation agent melt, resulting in that the Al-Mg-Si bond cannot be completely broken;

[0123] Compared with Example 4, no lithium fluoride is added in the transformation agent in Comparative Example 7, and the aluminum recovery rate in Comparative Example 7 is reduced by 48.7%, and the platinum group metal enrichment multiple is reduced by 5.63, which proves that the addition of LiF in the present application can significantly improve the transformation recovery of aluminum, and has a good enrichment effect on the platinum group metal, and the platinum group metal is almost not lost; this is because no lithium fluoride is added, the melt lacks coordination ions such as fluorine and lithium, which will not erode the cordierite structure, and the lack of lithium fluoride makes the melting point of the transformation agent higher, which can not form a high-temperature molten substance. Compared with Example 4, the lithium fluoride is replaced by calcium fluoride in Comparative Example 8, which causes a significant decrease in aluminum recovery rate, which further proves that the appropriate amount of lithium fluoride can improve the transformation of aluminum and the enrichment of platinum group metal.

[0124] The above-mentioned detailed description of the method for recovering aluminum and enriching noble platinum group metal from cordierite type waste catalyst according to the reference examples is illustrative rather than limiting, and several examples can be listed according to the limited range, so the changes and modifications without departing from the overall concept of the present application shall be within the protection scope of the present application.

Claims

1. A process for the recovery of aluminum and the enrichment of precious platinum group metals from a cordierite-type spent catalyst, characterized in that, The method comprises the following steps: 1) grinding, calcining and cooling the spent catalyst; 2) mixing the material obtained in step 1) with sodium carbonate, calcium oxide and lithium fluoride uniformly, and then calcining the mixture at 880-1000 ℃; 3) water leaching and filtering the calcined material obtained in step 2) to obtain a filtrate containing sodium aluminate and lithium hydroxide and a leaching residue rich in platinum group metals; 4) passing CO2 gas into the filtrate containing sodium aluminate and lithium hydroxide obtained in step 3) for 10-30 min, filtering to obtain a precipitate and a filtrate, and calcining the precipitate to obtain aluminum oxide; 5) continuing to pass CO2 into the filtrate after concentration, keeping at 90-95 ℃ for 10-30 min, filtering to obtain a filtrate and lithium carbonate, and evaporating and crystallizing the filtrate to obtain sodium carbonate and recycling it to step 2).

2. The process for recovering aluminum and enriching platinum group metals from a cordierite-type spent catalyst according to claim 1, characterized in that, In step 1), the grinding is to a powder particle size of 100-200 mesh.

3. The process for recovering aluminum and enriching platinum group metals from a cordierite-type spent catalyst according to claim 1, characterized in that, In step 1), the calcining is at 450-550 ℃ for 0.5-1.5 h.

4. The process for recovering aluminum and enriching platinum group metals from a cordierite-type spent catalyst according to claim 1, characterized by, In step 2), the total amount of sodium carbonate, calcium oxide and lithium fluoride added is 2-3.5:1 by mass ratio to the material.

5. The process for recovering aluminum and enriching platinum group metals from a cordierite-type spent catalyst according to claim 1, characterized by, In step 2), the molar ratio among calcium oxide, lithium fluoride and sodium carbonate is (1-2):(1-4):(4-8).

6. The process for recovering aluminum and enriching platinum group metals from a cordierite-type spent catalyst according to any one of claims 1 to 5, characterized in that, In step 2), the calcining time is 60-120 min.

7. The process for recovering aluminum and enriching platinum group metals from a cordierite-type spent catalyst according to any one of claims 1 to 5, characterized in that, In step 3), the water leaching temperature is 50-90 ℃, and the liquid-solid ratio of water leaching is (3-6):

1.

8. The process for recovering aluminum and enriching platinum group metals from a cordierite-type spent catalyst according to any one of claims 1 to 5, characterized in that, In step 3), the platinum group metals are recovered from the leaching residue rich in platinum group metals by a pyrometallurgical method.

9. The process for recovering aluminum and enriching platinum group metals from a cordierite-type spent catalyst according to any one of claims 1 to 5, characterized in that, In step 4), the pH of the filtrate is kept at 6.9-7.

1.

10. The process for recovering aluminum and enriching platinum group metals from a cordierite-type spent catalyst according to claim 1, characterized in that, In step 5), the pH of the filtrate is kept at 10.4-12.1.

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