Study of the relationship between the zeta potential and floatability of cassiterite fine fractions

This article is a continuation of the authors’ research on improving the flotation process for fine tin products using zeta potential measurements on particle surfaces. The aim of the research is to establish the possibility of using certain reagents to intensify the flotation of fine cassiterite particles and to identify the mechanism behind the effect produced by the reagents on the surface of slurry particles in cassiterite flotation using zeta potential measurements. The results of experiments to select the best collector are presented, with salicylhydroxamic acid identified as the best option. Sodium hexametaphosphate pretreatment of a flotation slurry consisting of fine particles enables a more efficient cassiterite flotation, which is explained by the negative value of the z-potential for the particle surface. The use of sodium hexametaphosphate improves the yield by up to 3 %, with the mass fraction of tin growing from 1.2 to 1.75 %, and the recovery improving from 40 to 75 %. The results of z-potential measurements for the particle surface in the process of flotation indicate that its positive values are not always required and that the combined action of oxalic and sulfuric acids with salicylhydroxamic acid at a z-potential of –0.7 mV renders the maximum tin grade of 2.22 % in the froth flotation product. Gravity treatment of the flotation concentrate on concentration tables allows obtaining conditioned concentrates with the mass fractions of tin of 23.4 and 30.6 %. Finding the extremum of the z-potential for the particle surface during the flotation of tin minerals allows predicting the concentration results.