▎ 摘　　要

NOVELTY - Natural graphite flakes and mixture containing 65 wt.% concentrated nitric acid and 98 wt.% concentrated sulfuric acid are placed in a reactor. To the resultant product, 30 wt.% hydrogen peroxide is added, stirred, filtered and washed. The resultant product is dried to obtain layered graphite. The layered graphite is immersed in aqueous solution of volatile acid, filtered, washed and dried, to obtain acidified layered graphite. The acidified layered graphite is added to solvent containing a surfactant, and ultrasonically peeled, to obtain graphene dispersion liquid. USE - Preparation of graphene dispersion liquid (claimed). ADVANTAGE - The method enables simple, environmentally-friendly and energy-saving large-scale preparation of graphene dispersion liquid having high quality. DETAILED DESCRIPTION - Natural graphite flakes and mixture containing 65 wt.% concentrated nitric acid and 98 wt.% concentrated sulfuric acid are placed in a reactor. To the resultant product, 30 wt.% hydrogen peroxide is added, stirred at 35 degrees C, filtered and washed with water to pH of 7. The resultant product is dried at 60 degrees C for 8-12 hours to obtain layered graphite. The layered graphite is immersed in aqueous solution of volatile acid having pH of 1-3. The aqueous solution of volatile acid is filtered, washed with water to pH of 7 and dried at 60 degrees C for 8-12 hours, to obtain acidified layered graphite. The acidified layered graphite is added to solvent containing a surfactant, and ultrasonically peeled under ultrasonic power of 500 W for 30-90 minutes, to obtain graphene dispersion liquid. The mass-volume ratio of layered graphite and solvent is 1 g:100-200 ml. The mass ratio of layered graphite and surfactant is 1 g:0.5-2 g. The mass-volume ratio of natural graphite flakes, mixture of concentrated nitric acid and concentrated sulfuric acid, and hydrogen peroxide is 1 g:5-10 ml:l-2 ml. The volume ratio of concentrated nitric acid and concentrated sulfuric acid is 1:1-3.