Effect of Ca(II) on anionic/cationic flotation of magnesite ore

Abstract

In the flotation of magnesite ore, dolomite dissolution and poor water quality can lead to the accumulation of Ca2+ in backwater and a slurry of flotation, which can give rise to many problems in the separation of magnesite, dolomite and quartz. This research analysed the effect and mechanism of Ca2+ on the anionic/cationic flotation behavior of magnesite, dolomite, and quartz based on flotation tests, zeta potential tests, adsorption tests, Fourier transform infrared spectroscopy (FTIR) tests, and X-ray photoelectron spectroscopy (XPS) tests. When LKD (a cationic collector) was used as a collector, Ca2+ inhibited all three minerals via adsorption onto the mineral surface and increased positive electricity. When sodium oleate (NaOL) was used as the collector, Ca2+ precipitated with NaOL and adsorbed onto the mineral surface. The adsorption of magnesite and dolomite by precipitation of calcium oleate (CaOL) was found to be weaker than the direct adsorption of NaOL, resulting in the inhibition for magnesite and dolomite, while quartz is activated. In addition, both sodium hexametaphosphate and sodium silicate weakened the effect of Ca2+ by forming compounds. Magnesite and dolomite with NaOL can be strongly depressed by calcium hexametaphosphate.