| dc.description.abstract | Iron is the fourth most abundant element in Earth's crust and the main industrial metal. The iron ore deposits are widely distributed around the world and can be found in different geological epochs, especially in the Precambrian. The chemical concentration of iron by laterization in the banded iron formations originated the largest deposits of iron ore from Brazil and the world. In specific regions of the iron formations are found iron ores associated with amphiboles, inosilicates that harm the flotation process. The Iron Ore Quadrangle, for example, presents Proterozoic banded iron formations and can be divided into four metamorphic zones in relation to amphiboles (grunerite, cummingtonite, actinolite and tremolite and anthophyllite). These minerals affect the flotation process due to its characteristic crystal structure and the chemistry of its surfaces that allows the release of ions in the pulp, especially calcium and magnesium ions, which may adsorb other minerals, preventing the selective action of the collector. Given the difficulty in processing amphibolites iron ores, millions of tons of iron oxides are lost annually. The usual tests for the flotation of iron ore often do not enable to obtain adequate results in the flotation, in other words do not produce iron ore concentrates with appropriate specifications to the market or recovery viable rates, when amphiboles are present in the ore. The introduction of oxalic acid in flotation tests, the mixing of reagents and the combination of concentration methods have shown great potential for a significant improvement in the selectivity of the process. Detailed studies were carried out with different reagents and amphiboles in order to understand the behavior of amphiboles through microflotation tests and zeta potential measurements. The results showed that quaternary ammonium salts can be used as collectors of amphiboles and the mixture of salts has the potential for industrial use | |
