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INVENTION
Patent of the Russian Federation RU2103395
A METHOD FOR EXTRACTING PLATINUM FROM PROCESSED CATALYSTS
The name of the inventor: Buchikhin EP; Kuznetsov A.Yu .; A. Chekmarev; Lavrentyev, IP; Lavrentieva E.A.
The name of the patent holder: Limited Liability Company "Company" Oriya "
Address for correspondence:
Date of commencement of the patent: 1996.09.18
Use: refers to the extraction of platinum from spent platinum catalysts.
SUMMARY OF THE INVENTION: the treatment of catalysts is carried out at a temperature of 95-103 ° C. with a mixture with a hydrochloric acid content of 4-7 mol / l , hydrogen peroxide of 1-4 mol / l , dimethylformamide 0.5-3.0 mol / l , and reduction Platinum from solutions is produced by the products of hydrolytic cleavage of dimethylformamide at a pH of 3-4 and a temperature of 90-105 ° C. The solution after washing the substrate is sent to the reduction of platinum, after reduction of platinum dimethylformamide is regenerated and the solution is directed to catalyst treatment after regeneration. The method makes it possible to increase the efficiency, processibility of the process by using dimethylformamide as a regenerable solvent and a reducing agent, which excludes environmental pollution by toxic gases and effluents.
DESCRIPTION OF THE INVENTION
The invention relates to methods for extracting platinum waste platinum catalysts of oil refining with a base of alumina and can be used in the processing of secondary raw materials.
A method is known for the extraction of platinum from platinum-containing catalysts with a base of alumina over which the catalyst is chlorinated in dry form by purging the layer of material with chlorine at a temperature of 300-500 ° C or as a suspension in a solution of hydrochloric acid at the boiling point of the suspended solution.
Disadvantages of this method are associated with the environmental hazard of the chlorination process caused by the release of toxic gases and waste waters, a high reaction temperature in the case of chlorination with chlorine gas, irreversible loss of a part of the base dissolving in concentrated hydrochloric acid in the case of liquid-phase chlorination. For the separation of platinum from the solution, multi-stage additional operations are necessary.
A method [2] for extracting platinum from spent platinum catalysts is also known. According to the known method, the catalyst masses from gamma- Al 2 O 3 D> are treated with a mixture of 30% hydrogen peroxide and 1-12N. of hydrochloric acid. Then, the leached base is washed with hydrochloric acid with a concentration of at least 5%. Noble metals are reduced with hydrogen or hydrazine.
Disadvantages of the method are associated with the use of expensive reagents for the precipitation of platinum metals, irreversible losses of excess reducing agents, the production of a large number of toxic waste waters requiring purification.
The object of the invention is to provide a method for recovering platinum from spent platinum catalysts by using dimethylformamide as a generated solvent and a reducing agent.
The technical effect of the proposed invention is to exclude environmental pollution by toxic gases and waste water, increase the profitability of the production of platinum from spent catalysts.
The object is achieved in that in the process for recovering platinum from spent platinum catalysts, including treating the catalyst with a mixture of hydrochloric acid and hydrogen peroxide, washing the base with hydrochloric acid, reducing platinum from the solution according to the invention, the catalyst treatment is carried out at a temperature of 95-103 ° C. , Mixture of dimethylformamide with the following ratio of ingredients, mol / l :
Hydrochloric acid - 4-7
Hydrogen peroxide - 1-4
Dimethylformamide 0.5-3
And the reduction of platinum from the solution is carried out by the products of hydrolytic cleavage of dimethylformamide at a pH of 3-4 and at a temperature of 90-105 ° C , after the reduction of platinum, demethylformamide is regenerated and the solution after regeneration is directed to catalyst treatment. In addition, the solution after washing the substrate can be sent to the recovery of platinum.
After reduction and separation of platinum, the solution is regenerated by introducing hydrochloric acid into it and heating it. After that, hydrogen peroxide is introduced into the solution and sent to the catalyst treatment.
The washing of water as dimethylformamide ( DMF ) and platinum compounds accumulate in them is directed to the reduction of platinum, after which it is acidified, heated and returned back to the process. As the quality of the washing water deteriorates, they are removed from the process and dispersed.
The lower temperature limit of catalyst treatment of 95 ° C is due to the fact that at a lower temperature the dissolution of platinum proceeds slowly. The upper temperature limit, equal to 103 ° C, is due to the boiling point of the leach mixture.
The lower temperature limit for the reduction of the mixture is due to the fact that at a lower temperature the platinum reduction reaction is difficult. The upper temperature limit is due to the boiling point of the mixture. At pH <3, no release of platinum and solution occurs due to the low degree of hydrolysis of DMF. At pH> 4, aluminum and iron hydroxides precipitate out of the solution.
Example 1
10 g of catalyst AP-56 (0.4% platinum, Al 2 O 3 base) was treated for 3 hours with 100 ml of a mixture containing 5.88 mol / l HCl, 1.36 mol / l H 2 O 2 , 2, 59 mol / L DMF in a beaker with a stirrer at the boiling point of the mixture ( 102-103 ° C ). The solution was filtered, the base was washed with 10% hydrochloric acid. The mother liquor was treated with 10 N HCl . NaOH solution to pH 3 , then heated for 0.5 h in a stirred and heated reactor at 95 ° C.
The precipitated platinum was filtered off. The recovery of platinum from the catalyst was 93.5% .
Example 2
10 g of catalyst AP-56 (0.4% platinum, Al 2 O 3 base) was treated for 3 hours with 100 ml of a mixture containing 5.88 mol / l HCl, 1.36 mol / l H 2 O 2 , 2, 59 mol / L DMF in a stirred and heated reactor at 95 ° C.
The solution was filtered off, the base was washed with 10% hydrochloric acid. The reduction was carried out in the same manner as in Example 1 . The recovery of platinum from the catalyst was 91.4% .
Example 3
10 g of catalyst AP-56 (0.4% platinum, Al 2 O 3 base) was treated for 3 hours with 100 ml of a mixture containing 5.88 mol / l HCl, 1.36 mol / l H 2 O 2 in a beaker With a stirrer at the boiling point of the mixture. The solution was filtered off, the base was washed with 10% hydrochloric acid. Platinum was reduced with hydrochloric acid hydrazine. The recovery of platinum from the catalyst was 98.5% .
Example 4
10 g of catalyst AP-56 (0.4% platinum, Al 2 O 3 base) was treated for 3 hours with 100 ml of a mixture containing 5.88 mol / L HCl, 1.36 mol / L H 2 O 2 , 1, 29 mol / L DMF in a beaker with a stirrer at the boiling point of the mixture (102-103 ° C) . The solution was filtered, the base was washed with 10% hydrochloric acid. The reduction was carried out in the same manner as in Example 1 . The recovery of platinum from the catalyst was 98.5% .
Example 5
The mother liquor from Example 4 was injected with hydrochloric acid to a concentration of 5 mol / l , heated for 1 hour at 50 ° C. , hydrogen peroxide was added to a concentration of 1.36 mol / l.
10 g of catalyst AP-56 (0.4% platinum base Al 2 O 3 ) was treated for 3 hours with the resulting mixture in a beaker with a stirrer at the boiling point of the solution. The solution was filtered off, the base was washed with 10% hydrochloric acid. The reduction was carried out in the same manner as in Example 1 . The recovery of platinum from the catalyst was 95.4% .
Example 6
The wash solution from Example 5 was treated with 10 N HCl . NaOH solution to pH 4 , and then heated for 1 hour in a stirred and heated reactor at t = 95 ° C.
The precipitated platinum was filtered off. Thus, it was possible to increase the extraction of platinum in Example 5 to 98.3% .
CLAIM
A method for recovering platinum from spent catalysts, comprising treating the catalyst with a mixture of hydrochloric acid and hydrogen peroxide, washing the base with hydrochloric acid, recovering platinum from the solution, characterized in that the catalyst treatment is carried out at a temperature of 95 ° -103 ° C. with a mixture further comprising dimethylformamide, Hydrochloric acid 4- 7 mol / l , hydrogen peroxide 1 4 mol / l, dimethylformamide 0.5-3 mol / l , the reduction of platinum from the resulting solution is carried out at pH 3-4 and at a temperature of 90- 105 ° C obtained after the reduction of platinum The solution is subjected to regeneration and directed to catalyst treatment, and the solution after washing the substrate is sent to the reduction of platinum.
print version
Date of publication 07.11.2006гг
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