Extraction of graphite by hydrofluoric acid method

Hydrofluoric acid is a strong acid that can react with almost any impurities in graphite. Graphite has good acid resistance, especially hydrofluoric acid, which determines that graphite can be purified with hydrofluoric acid. The main process of the hydrofluoric acid method is the mixing of graphite and hydrofluoric acid. The hydrofluoric acid reacts with impurities for a period of time to produce soluble substances or volatiles, which are washed to remove impurities, dehydrated and dried to obtain purified graphite.

Hydrofluoric acid reacts with Ca, Mg, Fe and other metal oxides to form a precipitate. The resulting H2SiF6 dissolves in the solution and can remove Ca, Mg, Fe and other impurities. Hydrofluoric acid is highly toxic and pollutes the environment seriously. Cooperating with other acids to purify graphite can effectively reduce the amount of hydrofluoric acid. Hydrofluoric acid purification of graphite has the advantages of simple process flow, high product quality, relatively low cost, and little impact on the performance of graphite products. However, hydrofluoric acid is highly toxic, and safety protection measures must be taken during use. The waste water must be treated before it can be discharged, otherwise it will cause serious pollution to the environment.