Abstract: The research on purifying feldspar-quartz ore of Chaoyang District in Liaoning Province was carried out by reverse floatation, which used sodium oleate as activator of feldspar, sodium hexametaphophate as depressor of quartz and lauryl amine hydrocloride as collector for feldspar. The results of flotation at pH=5.0 revealed that the rougher concentrate of desliming-reverse floatation has a 99.62% SiO₂ grade and 60.42% recovery from a feed containing 93.01% SiO₂ and 5.28% Al₂O₃ with a grinding fineness of -0.050 mm 85%, from which, the final product with a 99.95% SiO₂ can be obtained by re-grinding, re-flotation and concentrate desliming. The SEM and EDS results on the floatation products revealed that the key in the powder quartz purification is to remove the fine slime covered on the concentrate.

Key words: Quartz purification, SEM, Floatation, Slime