Sustainable mining of natural vein graphite via acid-extraction from waste attached to rock pieces of vein banks.

A procedure based on acid extraction using a mixture of conc. sulfuric and nitric acids (8:1) to recover graphite attached to rock pieces of the vein contact zones of graphite mines, is developed as a sustainable mining practice. When the extracted graphite is heated at 600 °C for 15 min, it is converted to a highly expanded form resembling worm-like structures.