Processamento de cassiterita ultrafina por agregação hidrofóbica.

Abstract

The present work had as the objective, in laboratory scale, the processing of ultrafine cassiterite by hydrophobic aggregation, employing as surfactants: sodium oleate, dodecylamine chloride and sodium dodecyl sulfate. The main parameters studied were: grain size of the that must be put together with the cassiterite (~5microns), pH of the suspension, concentration of the surfactant, rate and time stirring. Firstly, it was made the purification of the sample of a concentrated of cassiterite through magnetic separation, deslaming and heavy liquid separation. The purified sample showed a grade of 73,08 % of Sn02. Tests of microflotation and zeta potential were also made, from where referencial values of some parameters were obtained, which were correlation with the results of hydrophobic aggregation, with the aim of discussing the actuating mechanisms in the process. The tests of aggregation were made in an acrylic cylindrical cell with 600 mL of capacity coming from six baffles. The results showed that the best conditions for hydrophobic aggregation of cassiterite with the sodium oleate were: grain size (-53+38) microns, pH 8,0, concentration of 5x10"4 M, rate and time stirring of 750 rpm and 60 minutes respectively; and with dodecylamine chloride were: grain size and concentration were the some in relation to the previous case, pH 10,0, agitation rate of 250 rpm and stirring time of 1 minute. It was found out that for the cassiterite/oleate system, besides effect of the studied parameters, the aggregation depended on the degree of hydrophobicity of the mineral. Whereas for the cassiterite/dodecylamine chloride the aggregation depended mainly on the action of hydrophobic forces and partly on the zeta potencial of the mineral In terms of efficiency, the dodecylamine chloride, was too much better, with significant reduction!of the rate and time of agitation, that in cases of industrial potencial aplications it would have advantages of reducing the energetic waste.