Abstract: Taking water glass or sodium hexametahposphate as an inhibitor, did the reverse flotation by cationic collector Wely to desiliconize the magnesite from Haicheng area Liaoning province, and compared the results with common used lauryl amine collector. The experiment results show that the suitable value of pH is 5； under the suitable dosage, these two kinds collectors combined with water glass or sodium hexametahposphate all can get the magnesite concentrate with MgO grade＞47%, SiO₂ content＜0.2%，but the recovery rate of MgO with Wely which can get 77.15%~83.64% higher 2.15~4.06 percentage point than lauryl amine, Wely has the better selective collecting ability to silicate minerals；the dosage of water glass as inhibitor is 10 times than sodium hexametahposphate and the concentrate recovery rate is low, so sodium hexametahposphate is more suitable than water glass as the inhibitor to magnesite reverse flotation.

Key words: Magnesite, Reverse flotation, Wely, Lauryl amine, Water glass, Sodium hexametahposphate