Production of an Iron Ore Super-Concentrate From the Samarco Concentrator Via Flotation

摘要

With the aim of producing a concentrate with silica content lower than 1.0 per cent SiO_2, laboratory experiments were conducted using a sample of the final concentrate from the Samarco iron ore flotation plant (mechanical cells circuit). The sample contained 3.08 per cent SiO_2. This sample was split in two size ranges: >105 mu m and <105 mu m. The <105 mu m fraction, representing 76.7 per cent of the initial mass, was refloated, generating a concentrate containing 0.61 per cent SiO_2. The >105 mu m fraction, representing 23.3 per cent of the initial mass, was re-ground to 100 per cent <105 mu m, deslimed, and refloated. Concentrates with 0.90 per cent SiO_2 content were obtained. Considering the mass proportions of the two size fractions, the calculated silica content of the combined concentrate was 0.68 per cent, which is considered satisfactory for the objective of this investigation. The major reasons for the higher (0.90 per cent) silica content of the concentrate from the coarse fraction are the presence of silicon in the lattice of goethite and the presence of residual silicious slimes in the pores of porous hematite.