Study on washability of microcrystal graphite using float–sink tests

This article presented an experimental research on washability of microcrystal graphite using float–sink tests. Chemical and X-ray analyses showed that graphite, semi-graphite, meta-anthracite, and anthracite existed together in this microcrystal graphite sample; and the intergrowth relationship between microcrystal graphite and gangues was very complicated based on optical mineralogy research. The results of float–sink tests revealed that: for the −25 + 0.5 mm size fraction, about 68% (by weight) of microcrystal graphite was obtained at the density of 2.0 g/cm3, and the float product met the standard of commercial grade W65; for the −0.5 mm size fraction, 58% (by weight) of microcrystal graphite was floated at the density of 2.0 g/cm3, which met the standard of commercial grade W70. It can be concluded that microcrystal graphite may be upgraded by dense media separation (DMS) providing a float product using as the raw materials of casting or refractories.