Experimental study of the technological process for recovery of kaolin from flotation tailings

In order to expand the flotation tailings comprehensive utilization mode and realize high value-added utilization of valuable minerals in tailings, a new idea of realizing kaolin from flotation tailings is proposed, and the tailings from coal preparation plants in Tangshan area is taken as the object of study. Based on analysis of both mineral and size compositions of the tailings, it is targeted to recover the kaolin for use as porcelain and enamel making material. To achieve the goal, comparative experiments are conducted using carrier flotation, selective flocculation, high-gradient magnetic separation and chemical bleaching methods. As demonstrated by results of experiments, among the different methods used, the selective flocculation method is far inferior to the other ones in effect; the use of the carrier flotation method can lead to effective reduction of contents of iron and titanium, increase of ash of tailings and hence increase of content of aluminum; the use of the high-gradient magnetic method alone can produce a remarkable effect in reduction of iron content yet a less satisfactory effect in reduction of titanium content; and the chemical bleaching process when used alone can lead to effective removal of iron yet a relatively poor result in removal of titanium. Through the use of combined methods, and designed separation process flowsheet, a final product with a content of aluminum of 31.55%, an iron content of 1.59% and titanium content of 0.59% can be obtained, which is well up to the national standard-specified requirements for the class TC-3 products.