This work presents a study on the interference of kaolinite particles, smaller than 10 µm, in the performance of the cationic flotation of quartz. The surface properties control the effects of heteroaggregation and provide the creation of a coverage of these ultrafine on the coarser particle surfaces (slime coating), which makes it difficult for the collectors to adsorb and/or contact the air bubbles. The flotation experiments revealed that the etheramine collector used is capable of recovering 76.9% of ultrafine kaolinite in the absence of coarse quartz particles. On the other hand, the flotation results carried out with the binary mixture (quartz −150 + 45 µm and kaolinite ultrafines −6 µm) and in the presence of the same reagent system showed that kaolinite floats together with quartz depending on the content of ultrafines in the suspension. Micrographs from MEV/EDS showed that a heterocoagulation between coarse quartz particles and kaolinite ultrafine with a formation of hydrophobic agglomerates can be recovered in the flotation. 1 slime coating, coating , coating) andor or bubbles 769 76 9 76.9 hand 150 −15 4 6 − suspension MEVEDS MEV EDS 7 76. 15 −1

No mercado mundial, o valor dos metais tem aumentado consideravelmente. Todas as empresas mineradoras estão adotando medidas com o objetivo de otimizar seus processos de concentração, sempre visando retirar a máxima quantidade de metal de interesse do minério "ROM". Esse princípio é compatível com o alvo ambiental de minimização da geração de resíduos na atividade mineral. Beneficiando-se rejeitos, objetiva-se, tanto aumentar a produção, como, também, amenizar impactos ambientais. Esse trabalho apresenta uma análise dos fenômenos interfaciais que regem a flotação de silicatado de zinco, principalmente os finos, além de parâmetros para a concentração de rejeitos do circuito de flotação de willemita. As amostras de rejeito estudadas foram fornecidas pela Votorantim Metais, unidade de vazante. Depois de determinados quais reagentes respondem melhor ao processo e quais as suas condições ideais de dosagem, foram desenvolvidos testes de flotação em faixas granulométricas específicas, com o objetivo de se analisar o efeito do tamanho da partícula no processo de flotação.

In the world market, the metal prices have been increasing considerably. All mining companies have adopted actions with the objective of minimizing their concentration processes, enhancing the recovery of the metal bearing mineral from the ROM. This line is compatible with the environmental target of minimizing the generation of wastes in the mining activities. It aims at increasing the zinc production, while reducing environmental impacts. The goal of the present investigation is to analyze the interface phenomena that control the flotation of zinc silicate, mainly the fines, and to determine which conditions concentrate the tailings of the willemite's flotation circuit. The samples of tailings were supplied by Votorantim Metais, Vazante. After determining the best reagents for the flotation and their dosages, flotation's tests was carried out with specifically-sized samples, aiming to analyze the effect of the grain's size in the flotation's process.