Preparation of Low-Sulfur Expanded Graphite with Different Size Particles

Abstract

In this paper, results shows that expanded graphite of 128mL/g could be produced under the nitric acid treatment with the optimum mixture ratio of graphite: HNO3: H2O2: KMnO4 being 1(g):6(ml):2(ml):0.02(g), compared with the 145ml/g under the sulfuric acid treatment (graphite: H2SO4: H2O2 =1(g):3(ml):2 (ml)). The sulfur contents are ~0.10wt.% in EG with nitric acid treatment, and ~0.24wt.% in EG with sulfuric acid treatment, respectively. Therefore, the nitric acid treatment EG has little sulfur, which is greatly demanded in engineering application.