EM - Escola de Minas

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Kaolinite and hematite flotation separation using etheramine and ammonium quaternary salts.
(2013) Rodrigues, Otávia Martins Silva; Peres, Antônio Eduardo Clark; Martins, Afonso Henriques; Pereira, Carlos Alberto
Clay minerals are widespread in various types of mineral deposits. When present, they contribute to the high content of certain parameters such as silica, aluminium, and magnesium. This study aimed to find selectivity windows to separate hematite from a clay mineral (kaolinite) to allow reduction of the levels of silica and alumina in iron ore. The collectors used were: etheramine Flotigam EDA (EDA) and the ammonium quaternary salts: dodecyltrimethylammonium bromide (DTAB) and Tomamine Q-14-2 PG (AQ142). The depressant used was corn starch. The separation selectivity was achieved using DTAB in the pH range between 4 and 10. Using the collectors EDA and AQ142, the selectivity was obtained only in the presence of starch, at pH 10. Laboratory scale tests showed that as far as the particles size is concerned, better selectivity was achieved with finer particles. Circuit configurations including cleaner and scavenger stages, and pilot scale tests, will be required prior to a possible industrial implementation of the separation.
Reagents in calamine zinc ores flotation.
(2004) Pereira, Carlos Alberto; Peres, Antônio Eduardo Clark
Oxidised zinc ores are traditionallyfloated with fattyamines as collector. The effectiveness of this reagent requires a pre-sulph-idisation stage with sodium sulphide in conjunction with soda ash. Especiallyin the case of calamine ores, a dispersing agent becomes necessary. The collector must be emulsified with a fuel oil and the frother. This flotation system is characterised by the use of verylarge amounts of reagents. The proportion of each reagent in the reagents system must be carefullyoptimised
Dispersion effect on a lead–zinc sulphide ore flotation.
(2009) Silvestre, Marcelo Oliveira; Pereira, Carlos Alberto; Galery, Roberto; Peres, Antônio Eduardo Clark
This investigation was performed with samples from a lead–zinc sulphide deposit aiming at studying the influence of the dispersion degree of the particles in the pulp on lead and zinc flotation. Samples of ore and also of the minerals sphalerite, galena, pyrite, and dolomite were selected for the experiments. Nine types of dispersing agents and six blends among them were employed. A set of three dispersing agents was selected for the lead flotation and another set of three was chosen for zinc flotation. The criteria for the reagents selection were: high dispersion degree for galena and low for the other species, high dispersion degree for sphalerite and low for the other species, low dispersion degree for pyrite and high for the other species, and high dispersion degree for all species. Lead flotation experiments were performed under three conditions aiming at verifying the influence of the dispersing agent, of the pH, and of sodium carbonate. The zinc flotation tests were carried out at pH 10.5, modulated with lime. The use of dispersing agents in lead flotation did not improve the overall efficiency of the circuit for, despite improving the lead metallurgical recovery, they increase significantly the zinc losses in the lead concentrate. Sodium carbonate presented a low dispersion degree and did not affect the lead flotation results when compared with those achieved at natural pH and at pH 9.8 modulated with lime. Two dispersing agents were particularly effective in zinc flotation: dispersant 3223, a sodium polyac-rylate, and sodium hexametaphosphate. Both reagents significantly enhanced zinc recovery without impairing the concentrate quality.

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