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Obtaining automotive catalysts using as raw material inorganic solid waste with a high percentage of copper coming from the metalworking industries , machining and foundry


Currently the metal industry makes use of specific alloys containing copper as a major component, of this we can mention the brass alloys, which are composed of copper and zinc, and bronze alloys which are made of copper and tin. These alloys are mostly employed to produce parts, connections and pipes largely used in the automotive industry, among others. To obtain these alloys a lot of solid waste is co-produced and much of this waste is stored in nearby areas generating arrays of a solid residue which contains a large amount of metals such as zinc, copper, alumina and tin. Nevertheless, large deposits of these solid residues can increase the risk of environmental contamination of soil and watercourses. The production of copper alloy is made by melting of zinc and copper ingots metals as primary source of raw materials. It is also possible to produce copper alloys employing as a secondary source of raw materials these brass remelting ingots, scrap zinc or copper. The production of parts in metallurgical industry is done in rotary kilns, channel furnaces or induction where metals receive thermal load and reach the liquid stare and thereafter the liquid is drained, piped or transferred to molds. During this process occurs an unintentional production of oxidized zinc and copper which are formed by contact of metals in the liquid state with atmospheric oxygen. Thus, the oxidized portion of the lower density is concentrated on the supernatant and when the alloy solidifies, there is the deposition of oxides on the surface of the parts. The amount of oxidized material, or slag acts as an auxiliary melting this large amount of dross (oxidised zinc and copper) is ground, and then separates, and a small proportion of it which is named "metal drops" are returned to the fusion. The resulting solid material after the separation of the "metal drops" is stored in silos for oxidation of the zinc present in this mixture, and subsequent separation by sublimation. After separation of zinc, a large amount of remaining solids are disposed of in landfills of industrial wastes. The material disposed in such landfills containing high concentration of copper (92%), a significant portion of tin (7.7%) and other metals such as zinc (0.4 %), lead (0.16%) and aluminum (0.01%) This proposal focuses primarily on work in two areas related to environmental issues, the first one is to treat and reuse solid waste generated by the metallurgical, machining and foundry industries and use them as starting materials for the synthesis of new zeolite microporous materials both in micrometer and nanometer scales. The other aspect in which the project is focused is the application of these new zeolitic materials as adsorption agents and the catalytic conversion of noxious gases generated by the automobile engines. Therefore, molecular sieves synthesized from these industrial wastes is a added-value process with a potential industrial application. (AU)