▎ 摘　　要

NOVELTY - Preparing graphene by fractional purification involves adding aqueous ammonia to a solution of an oxidized graphene mixture with a large amount of impurities prepared by the Hummers method. The pH of the system is adjusted to 7. The mixture is allowed to react at 100 degrees C for 0.5-10 hours. The solution mixture is filtered and centrifuged. The precipitate is washed to remove dissolved impurity ions to obtain partially reduced graphene and manganese. The resultant is mixed with acid to precipitate manganese hydroxide. USE - Method for preparing graphene by fractional purification (claimed). ADVANTAGE - The method enables rapid separation and purification of the oxidized graphene, which is an intermediate product which facilitates large-scale industrial production of high quality graphene. DETAILED DESCRIPTION - Preparing graphene by fractional purification involves adding aqueous ammonia to a solution of an oxidized graphene mixture with a large amount of impurities prepared by the Hummers method. The pH of the system is adjusted to 7. The mixture is allowed to react at 100 degrees C for 0.5-10 hours. The solution mixture is filtered and centrifuged. The precipitate is washed to remove dissolved impurity ions to obtain partially reduced graphene and manganese. The resultant is mixed with acid to precipitate manganese hydroxide. The pH of the solution is adjusted to less than 7 to generate water soluble manganese (IV) ion which is removed by filtration to obtain pure partially reduced graphene which is further reduced to obtain high-quality graphene powder.