Solution chemistry study of salt-type mineral flotation systems: Role of inorganic dispersants

Interactions of salt-type minerals with common inorganic flotation depressants were investigated through solution chemistry calculations. From the constructed conditional solubility product limits and the actual solubility product lines of calcium silicate and phosphate in fluorite, calcite, and apatite single-mineral systems, the critical precipitation pH or concentration of silicate and phosphate in the corresponding mineral suspensions was determined. These values provided a fundamental basis for interpreting the results of flotation tests and were in line with the results of zeta-potential and dispersant adsorption measurements. The surface precipitation of calcium silicate or phosphate on fluorite and calcite was identified as a major depression mechanism. Selective depressing conditions for different salt-type minerals using Na2SiO3 and Na3PO4 as depressants were determined on the basis of solution chemistry calculations of the systems.