Estudo da recuperacao de cromo e niquel a partir de residuos gerados em aciarias brasileiras produtoras de aco inoxidavel utilizando um aparato em escala laboratorial na fusao dos reagentes
(Portugiesisch)
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Currently the Brazilian stainless steel production is around of 350000 tons per year. At the same time, the stainless steel industries generate more than 7000 tons of dusts with high content of chromium, nickel, and iron and lead. The amount of sludge generated during stainless steel production is not constant. The recycling of these wastes, besides solving the disposal and the environmental problems, makes it possible to recover valuable metals to the ironmaking process. The waste characterization is an essential step in a recycling process definition. One kind of dust and one kind of sludge, generated in the stainless steel production process, were studied in this work. The techniques used to characterize the wastes were chemical analyses, size separation tests, density measurements, X-ray diffraction analyses, and Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) microanalysis. The biggest portion of the dust and sludge particles had a spherical shape. This kind of particle was composed mainly of iron and chromium in the form of a spinel or oxides. Precipitation of a second phase was identified in some particles. Two briquettes were prepared with each waste, FeSi75 alloy and CaO. The studied wastes were RES3 and RES7. The FeSi75 alloy was used in two different particles sizes. The briquettes were introduced in a ASTM 1020 liquid steel at temperature of 1600 deg C. In this study, it was utilized a bench-scale equipment to melt the reactants. This study showed that besides the high recovery of chromium (98%) and nickel (100%) from the wastes, the new waste generated in the experiment (slag) is less aggressive to the environment than the initial wastes used for the production of the briquettes because it contains a smaller amount of heavy metals such as lead, chromium and nickel.
Estudo da recuperacao de cromo e niquel a partir de residuos gerados em aciarias brasileiras produtoras de aco inoxidavel utilizando um aparato em escala laboratorial na fusao dos reagentes
Weitere Titelangaben:
Benchmark-Untersuchung zur Wiedergewinnung von Chrom und Nickel aus Hüttenreststoffen brasilianischer Stahlwerke
Bench-scale study of the chromium and nickel recovery from wastes produced in Brazilian steel plants