Resumo

URDAY URDAY, Edwin; RODRIGUEZ VALDIVIA, Marcelo  e  SANCHEZ CHAVEZ, Giancarlo. Thermochemical conversion and microstructural analysis of self-reducing briquettes made of husk resulting from lamination coming from the forming process of steel in hot (Mill scale), and recycled graphite. Rev. Bol. Quim [online]. 2020, vol.37, n.5, pp.238-253. ISSN 0250-5460.

Abstract This paper shows the results of an investigation carried out to recycle the husk resulting from lamination coming from the (Mill Scale) forming process of steel in hot, in order to explore the possibility of obtaining sponge iron with a high metallic content. The experimentation consisted of forming self-reducing briquettes by mixing iron-oxide and graphite, and conducting them to a self-reducing process, varying the temperature from 900 to 1050 ºC for a minimum period of   30 min. expandable to 90 min, depending of the case. The husk and the reduced products obtained were characterized by applying mineralogical analysis techniques using fluorescence and X-ray diffraction, and chemical and mineralogical composition using scanning electron microscopy (SEM). In the reduced products the amount of mass loss and the change in the proportion of real weight were determined. Additionally, the determination of the degree of metallic conversion was possible by means of the analytical technique of the analysis of metallic Fe and total Fe for each sample. The results showed that at the conditions: [90 min    1050 ºC - 13% of graphite, the degree of metal conversion is equal to 99.9%], and for: [30 min    1050 ºC - 20.7% of graphite, a 95% of metal conversion is reached], and for: [90 min    1050 ºC - 20.7% of graphite, a 94.4% of metal conversion is reached]. In the case of the maximum degree of metal conversion, the formation of iron could be observed from the coalescing of metal points (whiskers) that leads to formation of dense and compact phases.

Palavras-chave : Self-reducing briquettes; Husk; Lamination; Metal conversion.

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