Purification of flotation graphite concentrates using ammonium bifluoride and sulphate. M.A. MEDKOV, G.F. KRYSENKO, D.G. EPOV, E.E. DMITRIEVA, P.V. SITNIK

Abstract

Purification of flotation graphite concentrates using ammonium bifluoride and sulphate. M.A. MEDKOV, G.F. KRYSENKO, D.G. EPOV, E.E. DMITRIEVA, P.V. SITNIK (Institute of Chemistry, FEB RAS, Vladivostok).

The results of study of the conditions of flotation graphite concentrates purification using ammonium hydrodifluoride and sulfate are presented. It has been shown that carrying out the fluorination process using 20 % excess of NH₄HF₂ makes it possible to achieve complete fluorination of the impurity components presented in graphite and to obtain a separation product with a carbon content not lower than 99.5 %. Subsequent processing of the separation product with ammonium sulfate at a temperature of 340°С makes it possible to obtain graphite with a purity of 99.97–99.98 %. The laboratory modes for combining these two processes of purification of graphite concentrate – fluorination of NH₄HF₂ and treatment of (NH₄)₂SO₄ – have been developed to obtain separation products with a carbon content not lower than 99.98 %.