New insights into the role of calcium dioleate in selectively separating fluorite from calcite during cleaning process

Abstract

Research on fluorite and calcite cleaning process have been ignoring the effects of calcium dioleate in pulp on flotation. In this study, flotation tests showed that flotation separation of fluorite and calcite could be achieved by the cleaning process under acidic conditions. Solution chemistry equilibrium calculations revealed that large amounts of calcium dioleate formed, and this compound was the main component in the cleaning solutions of fluorite and calcite under acidic conditions. Desorption and adsorption tests, contact angle measurements and atomic force microscopy (AFM) revealed the mechanism of selective separation of fluorite and calcite during the cleaning process under acidic conditions. Flotation tests showed that under acidic conditions, calcite flotation was strongly inhibited but fluorite flotation was less affected. Desorption and adsorption measurements and mineral surface contact angle analysis revealed that under acidic conditions, the calcium dioleate on the surface of calcite rough concentrate was desorbed into the solution, whereas the calcium dioleate in the solution did not readily absorb on calcite surface. The calcium dioleate on the surface of fluorite rough concentrate was hardly desorbed, whereas the calcium dioleate in the solution continued to adsorb on the surface. AFM intuitively confirmed the desorption of calcium dioleate from calcite surface and the adsorption of this compound on fluorite surface under acidic conditions. The selective adsorption of calcium dioleate on fluorite rough concentrate is an important factor that promotes the selective separation of fluorite and calcite during the cleaning process.