| abstract |
A process for treating carbon to reduce the ash content therein. The process involves treating the carbon with a fluorine acid solution which consists of an aqueous solution of hydrofluorosilicic acid and hydrogen fluoride, such that the available metal oxides are converted to metal fluorides and/or metal fluorosilicates and separating the treated carbon from the metal fluorides and/or metal fluorosilicates produced by the treatment. |