Influence of sodium silicate modulus on iron ore flotation with sodium oleate

•Direct iron ore flotation•Influence of sodium silicate modulus on iron ore flotation•Use of sodium oleate collector and sodium silicate depressant in iron ore flotation•Influence of sodium silicate on iron recovery, Fe grade and SiO2 grade in concentrate

This paper presents the influence of sodium silicate modulus on iron ore flotation with sodium oleate collector. Bench flotation tests were performed at pH 7 with actual iron ore from Quadrilátero Ferrífero, Brazil, with 42.8% Fe and 37.2% SiO2. Iron recovery averaged above 90% and the Fe contents in the concentrate were above 55%. The highest values of Fe grade and lowest of SiO2 were obtained with low levels of pulp density and sodium silicate dosage and with high level of sodium oleate. Increase of sodium silicate modulus had a small influence on response variables.