Surface charge and floatability of chromites from various localities. Fundamental studies on mineral processing of chromites (4th report)

The difference in surface charge and the floatability of chromites from various localities were clarified, and the relationship between mineralogical properties and these characteristics was investigated. The following is a summary of the results obtained. (1) Although the zeta-potential of chromites is influenced by gangue minerals accompanying them and the existence of metal ions in the chromite-water system, the i.e.p. (isoelectric point) of pure chromite which has a fresh surface is around pH 8.0 regardless of chemical composition. (2) There is considerable difference in floatability among the chromites investigated, which is greatly influenced by surface charge in the case of DAC and SDS as collectors. In addition, surface structure and crystallinity also produce an effect on floatability, that is, non-homogeneity of the surface and internal structure tends to depress floatability. The optimum particle size of a chromite is in the flotation range of 60-100 μm, with the floatability diminishing out of this range.