Dephosphorization of magnetite fines - part 2: influence of chemical variables on flotation kinetics

The influence of chemical and operational variables on the kinetics of apat ite notation from magnetite was investigated through batch notation tests i n a specially designed, temperature-controlled cell. The significance for t he apatite notation kinetics of four variables-collector, dispersant, pulp pH and temperature-and their interactions was examined through experiments conducted according to a full factorial design. The kinetic parameters of a first-order model with fast and slow floating distribution were utilized i n judging the influence of reagent dosage on notation performance. Statisti cal tests on phosphorus kinetic data show that collector and dispersant dos es have a significant effect on phosphorus recovery. However, pulp temperat ure is the dominant factor for notation rate. Increase in pulp temperature increases the notation rate. The recovery of phosphorus increases with incr easing collector dose at a given dispersant dose; however, the notation rat e decreases at doses of collector exceeding 65 g/t when the dispersant is a t a higher level. The effect of dispersant dosage on notation rate is obser ved to be nonlinear and quite complex owing to the interaction effects betw een collector and dispersant doses. The maximum recovery of phosphorus with minor loss of magnetite concentrate was obtained at pH 9, with either 30 o r 65 g/t collector. The optimum notation conditions were 65 g/t collector, 350 g/t dispersant, pH 8-9 and a pulp temperature of about 20 degrees C.