Abstract: In the floatation system with sodium oleate as collector， the floatability of magnesite， dolomite and quartz and the effects of regulators on floatabilitiy of those three minerals were studied. In addition，the influences of dolomite and quartz on the floatability of magnesite， the influence of dolomite on the floatability of quartz and the influence of dolomite on the floatability of the mixture of magnesite and quartz were researched， and their mechanisms were explored. The results show that taking sodium oleate as collector， the floatabilities of magnesite and dolomite are close，and sodium hexametaphosphate and sodium silicate can depress the floatability of magnesite and dolomite. Moreover， these three minerals have interactive effects each other. For example，adding dolomite or quartz can decline the magnesite recovery， and adding dolomite can improve the quartz recovery， which are basically caused by the dissolution of minerals and the coverage of minerals on each others.

Key words: magnesite, dolomite, quartz, sodium oleate, interactive effect