Silica and Iron Recovery from a Residue of Iron Ore Flotation

A study of silica and iron recovery from the iron ore concentration tailing is presented. The residue is composed of 40.1% Fe, 33.4% SiO2, 8.31% Al2O3, 0.08% P, and 0.34% MnO. The developed process of silica and iron recovery consisted of size classification, magnetic separation, and removal of impurities by leaching. A concentration of SiO2 from 33.4% to 67.0%, with 60.0% of mass reduction, was achieved by size classification. After magnetic separation, the SiO2 grade increased from 67.0% to 95.0%, in non-magnegtic fraction and iron increased from 40.1% to 60.2% in magnetic fraction. The iron content in magnetic fraction achieved the commercial grade. In order to increase the content of silica, the impurities removal from the non-magnetic fraction was studied. The leaching agents investigated were HCl, H2SO4, HNO3, HF, C6H8O7, (COOH)2∙2H2O and NaOH. A concentration of 98.0% SiO2 was attained with the acid digestion.