A influência de reagentes auxiliares de filtragem sobre a formação e umidade de tortas de rejeito de minério de ferro

Abstract

Alternative methods for the disposal of tailings in dams, such as dry stacking, are increasingly important in the mining scenario, especially regarding iron ore processing. The final dewatering of the tailings, aiming at stacking, is normally carried out by filtration. Auxiliary reagents (aggregants and surfactants) can improve filtration performance. In the present study auxiliary reagents that can improve filtration performance were tested: nonionic flocculants, organic cationic coagulants and a surfactant. The objective of this work was to find the best condition for the filtration of iron ore tailings. The filtration tests were carried out in the laboratory, using the leaf-test assembly. The results indicated a drop in moisture of up to 2.8 points compared to the blank test without the application of filter aids . The addition of the flocculant reduced the cake formation time, increasing the production. At low dosages, there was no increase in moisture. It was found that the addition of the surfactant caused a reduction in cake moisture, but also lower production. The addition of the organic coagulant provided an increase in production without an increase in moisture, at a lower dosage. Preliminary tests of iron ore tailings filtration carried out on an industrial scale, showed potential both in the application of flocculant, at low dosages, and in the application of the coagulant, increasing production by 50% and reducing moisture in the cake.