Concentration of manganese gondite by magnetic separation and flotation – a preliminary study / Concentração de gonita de manganês por separação magnética e flutuação - um estudo preliminar

Abstract

Traditionally, manganese mining exploited rich deposits and produced rich granular concentrates with high commercial acceptance. But the scarcity of these rich ores results in searches for new alternatives to support the market demand. This work, for example, proposed the evaluation of a low-grade manganese ore concentration, aiming to produce a concentrate to be destined steelmaking. The liberation study, realized in the characterization step, showed the associations between grouped manganese oxides/hydroxides, spessartine, and quartz (minerals with predominantly proportions in gondite). The material studied was a gondite (metasedimentary rock with low manganese content), submitted to characterization and pre-concentration. Flotation results pointed to a metallurgical reasonable recovery of 88.76%, but a product with manganese content equal to 21.51%, indicating a low enrichment of 1.11. The greatest metallic recovery was 92.48% to a size range of –147 +38 μm applying the magnetic concentration tests with field strengths of 15,500 Gauss. The magnetic concentration product with the best metallic recovery (92.48%) produced manganese content equal to 22.84%, representing an enrichment of 1.18. The BSE images revealed particles of manganese oxides with the liberated surface, but also the permanence of spessartine particles involved by the other manganese oxides.