Study on graphite demineralization by dilute acid/flouride treatment

Three natural graphites of different ranks were treated by dilute HCl and flouride solution under various conditions for the removal of mineral components. After the two - step treatment with HCl solution at 100��C for 2h, and then with flouride solution at 70��C for 2.5h, the ash content was reduced from 11.22% to 0.07%, while carbon content was increased to 99.93% for Datong graphite. under the same conditions, the ash content of Neimeng graphite was reduced from 4.33% to 0.2% corresponding to a carbon content of 99.98%. For other graphites, similar results were also obtained. The effects of temperature, concentration of HCl, flouride solution were examined. The experimental results indicate that not only our method has better effect for mineral removal in graphite, but also the reaction is mild, corrosion and cost are low. It has bright application prospect.