▎ 摘　　要

NOVELTY - Preparation of nano graphene involves mixing graphite powder with water, refining to obtain a slurry, extracting the slurry with water or liquid carbon dioxide as an extractant, filtering to obtain a filtrate, and drying. USE - Preparation of nano graphene (claimed). ADVANTAGE - The method is easy, economical and suitable for large-scale industrial production, and rapidly produces high quality nano graphene material with high yield and less energy consumption.