Produção de um pellet feed a partir da concentração do rejeito da flotação mecânica da SAMARCO

Abstract

This work investigated the possibility to produce a pellet feed with 1.0% of silica using a representative sample of the mechanical flotation tailings. This sample contained 11.0% Iron and presented a F80 and a d50 of 116µm and 63µm, respectively. Higher silica content was verified in the coarser fractions and larger iron content in the fraction -37µm. The specular hematite is the most abundant mineralogical phase in fraction -37µm. The technological tests involved four routes: magnetic concentration using Minimag (WHIMS), magnetic concentration using SLon, reverse flotation and direct flotation. The routes using the magnetic concentrator SLon, reverse flotation and direct flotation presented inferior results compared with the premise adopted in this study, that wasobtaining an iron content in the concentrate (rougher stage) higher than 34% and an iron recovery superior to 80%, not being accomplished concentration tests (cleaner stage) with the concentrate achieved using those three routes. Comparative tests between two pilot WHIMS, Minimag, supplied by GAUSTEC, and WHC, supplied by INBRÁS-ERIEZ, were accomplished for ten days. Those tests used part of mechanical flotation tailings. For those days were made comparative tests of asample also formed by the composition of all flotation tailings. There were no significant differences between performances of the two separators. When comparing mechanical flotation tailings with the composition of all the flotation tailings, the results were also similar.The best studied route consisted of using WHIMS as a rougher stage and columns as a cleaner stage. Using this route, it was possible to produce a pellet feed with 1.0% silica and with high specular hematite content.