The combined application of Na2SiO3 and Mn2+ enhancing the flotation separation of quartz and kaolinite by NaOL

Abstract

Kaolinite is mainly composed of silica-aluminate, which is difficult to be separated by conventional flotation chemicals due to the fact that it has the same surface chemistry as quartz. Therefore, in this paper, the impacts of Mn2+ and Na2SiO3 on the flotation separation of quartz and kaolinite were studies through flotation tests, SEM-EDS analysis, AFM analysis, XPS, FTIR, Zeta potential, and molecular dynamics. In the single-mineral experiments, the recoveries of quartz under the combined effects of Mn2+ and Na2SiO3 were 9.08 %, and that of kaolinite was 71.56 %. In the actual mineral experiment, the grade of Al2O3 in the final concentrate was 19.64 % with a recovery of 76.8 % and the grade of quartz in the final tailings was 91.24 % with a recovery of 21.75 %. The separation of quartz and kaolinite can then be performed. The tests and molecular dynamics verified that with the addition of Mn2+, the adsorption of NaOL on the quartz surface was inhibited, while that on the kaolinite surface was facilitated, which increased the hydrophilicity of quartz and the hydrophobicity of kaolinite, leading to the separation of the two kinds of quartz and kaolinite.