For the spent catalyst in which the carrier is difficult to be dissolved by the acid, the treatment by this method is relatively simple. Since the platinum group on the catalyst surface due to the surface of the platinum family metal catalyst in a highly dispersed state, which is much easier to dissolve than a corresponding pure metal. Metals such as platinum and palladium generally do not need to be dissolved in aqua regia, and can be introduced into the solution with hydrochloric acid. The concentration of hydrochloric acid is 0.1 to 12 mol/L, usually 2 to 9 mol/L. Practice has proved that if it is difficult to obtain a satisfactory leaching effect with a single hydrochloric acid, it is often necessary to add a suitable oxidizing agent to the hydrochloric acid solution to promote the dissolution of the platinum group metal. Commonly used oxidants are nitric acid, chlorine, hydrogen peroxide, sodium chlorate, and the like. For the support is γ-Al2O3 susceptible to acid dissolution, the spent catalyst is treated with hydrochloric acid The method of the oxidizing agent, a platinum group metal, and supports are often into solution, the aluminum salt solution to the phenomenon of de-prone body. In order to dissolve only the platinum group metal in the spent catalyst without dissolving the alumina in the support, the spent catalyst must first be subjected to a calcination treatment to remove the coke and convert the acid-soluble γ-Al 2 O 3 into acid-insoluble α-Al 2 O 3 . The catalyst for petroleum reforming and xylene isomerization is a platinum-containing γ-Al 2 O 3 supported catalyst, and the spent catalyst contains Al 2 O 396.5%, Fe 0.4%, SiO 20.7%, and Pt 0.35%. The metal platinum is adsorbed on the surface of the carrier or the voids of the carrier by fine particles (less than 500 mm, 70% to 80%). The spent catalyst adsorbs a large amount of organic compounds and surface carbon, first calcined at 1000-1100 ° C, eliminating carbon deposits and converting γ-Al 2 O 3 into inert α-Al 2 O 3 . Then, the spent catalyst was leached at 70 ° C for 6 to 2 hours with a 6 mol/L hydrochloric acid solution using sodium chlorate as an oxidizing agent. The leachate contains (g/L): Pt0.263, Al1.2, Fe0.07, HCl1.9 mol/L, and the composition of the solution is simple, and the platinum group metal can be enriched by displacement or extraction. If the catalyst contains ruthenium , it will be partially converted into a difficult-to-dip oxide state when calcined at a high temperature. The effective pretreatment method is to use a sodium borohydride alkaline solution for reduction to improve the leaching rate. Suzhou tolo precision molding co., LTD., mainly engaged in precision connector mold parts, auto connector mold parts, precision plastic mold, precision connector mold parts, precision molds, precision tungsten steel parts, precision molds, precision plastic mold, die-casting mold parts, cause mould parts, PG optical grinding, precision stamping die parts, precision circle and so on, welcome specifications variety of choose and buy Can be customized according to drawings, and the price of factory direct sales is more favorable, all kinds of materials are complete, from design to processing, we have packaging, professional customer service, to provide you with the best way to case. Electronic Plastic Parts,Automobile Plastic Parts For Car,Plastic Components For Car,Automobile Plastic Components Suzhou Dongye Precision Molding Co.,Ltd. , https://www.sjinjectionmolding.com
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