Elimination of the Adverse Effect of Calcium Ion on the Flotation Separation of Magnesite from Dolomite

摘要

The separation of magnesite from dolomite was studied by flotation tests, X-ray photoelectron spectroscopy (XPS), and zeta potential measurements in the presence of calcium ion (Ca 2+ ) dissolved from dolomite. Sodium oleate (NaOL) was used as collector, and sodium carbonate (Na 2 CO 3 ) and sodium hexametaphosphate (SH) were used as regulators. The results showed that SH had a good selective inhibition ability in pure mineral flotations of magnesite and dolomite. While in the presence of Ca 2+ dissolved from dolomite, magnesite and dolomite were both inhibited by SH. The separation of magnesite from dolomite cannot be realized because Ca 2+ can adsorb on the surface of magnesite in the form of CaCO 3 and change the surface properties of magnesite. Thus, the magnesite flotation was depressed. When the sequence of reagent addition was changed to add SH prior to Na 2 CO 3 , a complex was made by Ca 2+ reacting with SH, which avoided the adsorption of Ca 2+ on the magnesite surface and prevented the changing of the magnesite?￠????s surface properties. Then, after adjusting the solution pH with Na 2 CO 3 , the flotation separation of magnesite from dolomite could be achieved.