▎ 摘　　要

NOVELTY - Preparing graphene based on 18- mesh large flake graphite, involves preparing expanded graphite taking 18 meshes of large flake graphite in the beaker under the condition of ice water bath, adding concentrated sulfuric acid into the beaker, continuously slowly adding hydrogen peroxide (H2O2) after the system, fully reacting and cooling to room temperature, standing for 24 hours at room temperature to obtain expanded graphite (EG), preparing graphene oxide by the obtained EG water washing and drying to prepare the secondary intercalation stripping to prepare graphene oxide (GO), the concentrated sulfuric acid and concentrated phosphoric acid are configured to be mixed acid solution in ice water bath, uniformly mixing the dried EG and potassium permanganate, slowly adding the mixed acid solution and further stirring, uniformly fully stirring and reacting the mixed system in the water bath boiler of 58-62℃ for 7-9 hours. USE - Method for preparing graphene based on 18- mesh large flake graphite. ADVANTAGE - The method is capable of effectively and economically preparing the graphene and heat-conducting film with good heat- conducting performance and high yield and without defects, and effectively removes the oxygen-containing functional group in the film material, and recovers the crystal structure, and improves the heat conducting performance of the film. DETAILED DESCRIPTION - Preparing graphene based on 18- mesh large flake graphite involves preparing expanded graphite taking 18 meshes of large flake graphite in the beaker under the condition of ice water bath, adding concentrated sulfuric acid into the beaker, continuously slowly adding hydrogen peroxide (H2O2) after the system, fully reacting and cooling to room temperature, standing for 24 hours at room temperature to obtain expanded graphite (EG), where the proportion of 18-mesh special flake graphite and concentrated sulfuric acid and H2O2is 1g and 18-22 mL and 4-6 mL, preparing graphene oxide by the obtained EG water washing and drying to prepare the secondary intercalation stripping to prepare graphene oxide (GO), the concentrated sulfuric acid and concentrated phosphoric acid are configured to be mixed acid solution in ice water bath, uniformly mixing the dried EG and potassium permanganate, slowly adding the mixed acid solution and further stirring, uniformly fully stirring and reacting the mixed system in the water bath boiler of 58-62℃ for 7-9 hours, the proportion of the potassium permanganate to the concentrated sulfuric acid and the concentrated phosphoric acid is 4-6 g and 90-110mL and 32-38mL ratio of the potassium permanganate to the concentrated sulfuric acid is 90-110mL; centrifugal washing removing excess of potassium permanganate after the reaction is finished, the mixed system of the ink green in ice water bath and dropping H2O2into the system and stirring the color of the mixture becomes bright yellow from green to green, using ultra-pure water to centrifuge and water washing the golden yellow mixture for several times to amber oxidation graphene water solution, and then centrifugally collecting the precipitate, and using ultra-pure water to prepare graphene oxide (GO) aqueous solution for subsequent film forming. An INDEPENDENT CLAIM is included for amethod for preparing heat-conducting film based on the method for preparing graphene based on 18-mesh-based flake graphite which involves: a. defoaming the GO aqueous solution under the vacuum environment for several times and performing ultrasonic dispersion, realizing removing bubble in the mixed system and realizing subsequent film formation, no defect; b. coating the defoaming GO aqueous solution on the substrate to form a film drying in a vacuum drying box to obtain the GO film; c. putting the dried GO film deposited on the glass substrate in the solution of hydrogen iodide to reduce, obtaining the reducing graphene oxide film (HI-rGO), under the condition of water bath heating at 76-84 ℃; d. collecting the HI-rGO film in the ultra-pure water to soak and wash the residual hydrogen iodide solution, fixing the washed HI-rGO film in the clamp of the graphite plate, drying at the temperature of 48-52℃, clamping the film in two pieces of paper, continuously rolling in the roller press, drying the paper and the middle film together in the drying box of 58-62℃, separating the film from the paper, continuously rolling the film along the X axis and the Y axis for many times; and e. putting the HI-rGO film after rolling into a smooth graphite plate clamp and clamping the HI-rGO film in the limited space, putting the mould in the high temperature tubular furnace firstly introducing argon gas to remove the air in the tubular furnace then controlling the air flow to perform high temperature reduction.