FERRONIOBIUM ALLOY FINES AGGLOMERATION THROUGH BRIQUETTING
André Carlos Silva, Mariana Rezende de Barros, Kléber Silva Macedo, Elenice Maria Schons Silva
Abstract
Brazil is the largest producer of Niobium alloys, with a production of 58,000 tons of Nb2 O5 concentrate in 2016, corresponding to a 92.81% of the world production. The Brazilian Niobium ores grades vary from 0.51 to 2.71%. Ferroniobium (Fe-Nb) is an iron niobium alloy with niobium content of 60-70%. It is the main source for niobium alloying of HSLA steel and covers more than 80% of the worldwide niobium production. In 2014, Brazil produced 51,737 tons of Fe-Nb, being around 90% of it for exportation. In the final stage of the Fe-Nb production, the alloy needs to be crushed in a jaw crusher, which generate fine particles (around 26% of the feed below 10 mm at Niobras/CMOC). The selling price of the fine particles have a significant loss in the market, since the fine particles cannot be used directly in steelmaking. A process to agglomerate the Fe-Nb fine particles into briquettes with size and chemical composition similar to original products was developed. Organic binders were used as well as a lubricant agent. The briquettes were characterized both physically and chemically. For the physical characterization, the briquettes were tested for mechanical and water resistance, thermal shock and Brinell hardness. Briquettes containing addition of 3% of zinc stearate, 2% of iron powder, and 1% of water reached a Niobium content above 62% and contaminants levels of below the standard Fe-Nb specifications. The results indicate that Fe-Nb alloy fines can be technically and economically agglomerate by briquetting.
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References
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