Abstract: There are 79.82% of kaolinite, 18.14% of pyrite and only 2.06% of impurities in a certain kaolin ore.To eliminate the effects of pyrite on kaolin, and realize comprehensive utilization of pyrite, laboratory tests of sulfur flotation are carried out.According to the characteristics that the kaolin is easy sliming and the particles size of pyrite is small, the imitating closed-circuit grinding was adopted in the laboratory to get fine grinding for the raw ores.The results showed that under grinding fineness of about -0.043 mm 95%, the pyrite was fully dissociated, and the interference of kaolin sliming to the sulfur flotation process was reduced.With acidic sodium silicate as dispersant of kaolinite, butyl xanthate as collector of pyrite, sulfur concentrate with S grade of 48.77% and S recovery of 87.30% was obtained by adopting the closed-circuit flotation flowsheet of one roughing, two-cleaning and two-scavenging.And the products left in sulfur flotation tank, kaolin concentrate, can be directly used as low-grade ceramics raw material.

Key words: Kaolin, Pyrite, Imitating closed-circuit grinding, Acidic sodium silicate, Sulfur flotation