Technological characterization of kaolin tailing from small-scale mining in RN and PB states – Brazil

In small-scale mining in north-eastern Brazil, the exploitation of industrial minerals, where kaolin bearing pegmatites are mined, is common. The mineral processing of kaolin is based in mixer and classification by screen and cyclone. The overflow of cyclone is thickened and filtered by pressure filter. The product is dried for market. This work presents the results of tailings characterization. Mass balance was realized and recuperation of kaolin about 56% was identified. The feed grade of Al2O3 in the plant is 21.20%. The kaolin product for market sold by the company presents 37.19% Al2O3 and whiteness of 81.9%. The average Al2O3 content of the tailing is 15.55%. Minerals identified are feldspar, muscovite, tourmaline, illite and kaolinite. The −325# fraction of the tailings present Al2O3 grades with characteristics for market (Al2O3-35%) and whiteness of 79.7%. Values from 7 to 34 wt% of this −325# fraction were determined in the tailing samples analyzed; these results validate the feasibility of reprocessing the tailings for using in the ceramic industry.