A new chemical method for purification and surface modification of Sri Lankan vien graphite

Abstract

Sri Lanka has its own demarcated possession for the high quality vein graphite containing 95-98 % of initial purity of carbon.Presently Sri Lankan vein graphite is exported as a cheap raw material without any value addition. The present study focuses to find a cost effective and convenient new chemical method for the graphite purification and to modify the graphite surface using alkali chloride solutions for improving performance of a graphite electrode (for negative electrode) of batteries. Collected vein graphite samples were powdered and prepared samples (10 g of <53 μm) were treated for acid digestion method with a mixture of 5 % of HF, Con.H2SO4& Con.HNO3. 3.50 g of portions graphite powders were separately mixed with 100 ml of 0.1% LiCl, 0.1% KCl and 0.1 % NaCl aqueous solutions for preparing of surface modified graphite. The carbon content of the Needle Platy Graphite (NPG) variety has the highest carbon content and the purity of the samples has been enhanced after acid digestion treatment by removing impurities. The FTIR analysis proved that many of impurity related functional group bands have been removed from the surface modified NPG.The Lithium, Sodium and Potassium Chloride coatings were capable to improve the electric conductivity performance.