▎ 摘　　要

NOVELTY - Concentrated sulfuric acid, persulfate and hydrogen peroxide are added to natural crystalline flake graphite of different sizes and mixed at room temperature. Obtained aggregate is cleaned using pure water, repeatedly washed until pH value is neutral, and in-situ freeze-dried. The dried material is ultrasonically dispersed in an organic solvent, centrifuged and in-situ freeze-dried, to obtain graphene. USE - Preparation of graphene (claimed). ADVANTAGE - The method enables economical preparation of graphene by simple process under mild reaction condition.