Avaliação da flotação de minério de ferro de brucutu considerando a divisão em dois circuitos: grossos e finos

Abstract

This investigation aimed at understanding the behavior of each sample that constitutes the global feed of Brucutus flotation stage (AGFRBR), considering the future expansion of the concentrator including the processing in two size ranges, coarse and fine particles circuits. The present circuit consisting of conventional mechanical cells will receive the coarse material (-0.150 + 0.044mm); while the new flotation circuit will receive the fine particles blend (-0.044mm) and the grinding product. The samples were collected at the feed of the industrial flotation during distinct operation periods and the blend composed from the proposed mass balance. The reagents dosages were established based on the characteristics of the samples to be processed in each flotation circuit and in the industrial practice. A comparison between the results achieved with the sample UF1DBR (-0.150 + 0.044mm) and the global sample indicated that the first is more selective , resulting in lower silica contents in the concentrate, enhanced selectivity, and lower reagents consumption required for achieving the expected results; nevertheless iron recovery and content in the tailings were kept in similar levels. Achieving high quality concentrate and tailings with the blend was difficult due to the presence of high contents of contaminants impairing the quality of the final product. Partial dispersion of the sample and desliming significantly improves all the indicators of quality and recovery. The analysis of the achieved results in the coarse particles flotation (-0.150 + 0.044mm) and the proposed blend showed increase in the mass and metallurgical flotation recoveries and enhanced process selectivity with a decrease in collector consumption of approximately 10%. Optimizations at plant site are expected to reduce depressant dosages required for both samples.