Flotação aniônica direta de minerais portadores de ferro com ácido graxo saponificado como coletor

Abstract

The demand for iron ore grows every day in the market, and due to the depletion of reserves with higher grades, the need arises for processing low grade iron ores, including tailings. Iron ore that contains quartz as its main gangue mineral can be floated in three different ways: direct anionic flotation of iron oxides at neutral pH; reverse anionic flotation of activated quartz with calcium ions at alkaline pH; reverse cationic flotation at alkaline pH. An alternative that has been studied is direct anionic flotation, as it is a technique indicated for low-grade ores or tailings discarded in dams. The objective of this work is to evaluate the performance of reagents that can increase the efficiency of the flotation of iron-bearing minerals from two samples: flotation feed (Fe of 52.1% e SiO2 of 22.9%) and magnetic separation tailings (Fe of 6.6% e SiO2 of 90.2%), from a mine in the Iron Quadrangle, by means of direct anionic flotation, using saponified fatty acid as collector and sodium silicate as depressant. The tests were carried out in the mini pilot plant of CETEM (Mineral Technology Center), located in Rio de Janeiro-RJ. The fatty acid and sodium silicate dosages were 200 g/t to 600 g/t and 800 g/t respectively for the flotation feed samples and 75 g/t to 150 g/t and 600 g/t respectively for the samples from the flotation. CMAI waste, at pH between 7.2 and 10.0. The best result was obtained with a collector dosage of 500 g/t, without depressant, generating a concentrate with Fe and SiO2 contents equal to 61.5% and 10.5%, respectively, with metallurgical iron recovery equal to 91.4 %. Given the high value of SiO2 obtained, it is necessary to plan new tests to adapt the product to the chemical specifications required by the market.