▎ 摘　　要

NOVELTY - Preparing high purity multi-layer graphene comprises e.g. (i) crushing (ii) molding (iii) cutting (iv) liquid oxidation: taking the graphite oxide, uniformly mixing, stirring and reacting, washing and filtering and drying, (v) solid oxidation (vi) ultrasonic process: placing the graphite oxide in a ultrasonic cleaning machine, ultrasonically processing, (vii) reducing: taking the graphene oxide, reducing agent and solvent, mixing uniformly, heating, stirring and mixing, and (viii) purifying: filtering, washing by using ethanol, centrifuging, and placing the precipitate in the oven and drying. USE - The method is useful for preparing high purity multi-layer graphene (claimed). ADVANTAGE - The method has convenient operation, low production equipment, low cost and is suitable for large-scale production. DETAILED DESCRIPTION - Preparing high purity multi-layer graphene comprises (i) crushing: using compact crystalline graphite as raw material, making the compact crystalline graphite into a crusher to crush, sieving with 200-300 meshes screen to obtain the graphite powder, (ii) molding: using single-layer flat continuous rolling method to processing the graphite powder, taking the graphite powder into the feeding device, uniformly spraying falls on the conveying belt, using pressure roller for rolling, and forming the graphite material layer, heating the graphite material layer, finally, taking out the graphite material layer is preliminarily forming into a roller control thickness in size, pressing for one time according to the needed thickness to obtain uniform thickness of the graphite plate, (iii) cutting: using cutting machine to cut the graphite plate with graphite, cutting it into needed size of graphite, (iv) liquid: taking the graphite oxide, uniformly mixing with liquid oxidant in a sealed reaction container, reacting for 1-4 hours in ice water, stirring and reacting for 0.5-2 hours at room temperature to obtain first suspension, taking the first suspension washing and filtering by deionized water until it is neutral and drying in the oven to obtain the dried product, (v) solid oxidation: taking the dried product, solid oxidant and solvent, mixing uniformly into a container with magnetic stirring in the sealed container, placing in a magnetic stirrer, heating at 30-70 degrees C, stirring and mixing for 2-4 hours to obtain second suspension, and taking the second suspension washing and filtering by deionized water until it is neutral and drying in the oven to obtain oxidized graphite, (vi) ultrasonic process: placing the graphite oxide in a ultrasonic cleaning machine, ultrasonically processing to obtain graphene oxide, (vii) reducing: taking the graphene oxide, reducing agent and solvent, mixing uniformly, adding into a sealed container with magnetic stirring, placing in the magnetic stirrer, heating at 40-60 degrees C, stirring and mixing for 2-5 hours to obtain third suspension, and (viii) purifying: filtering the third suspension, washing by using ethanol, centrifuging and settling for 3 times, washing the precipitate with deionized water, centrifuging and settling for 3 times, finally centrifugal settling for 3 times by ethanol and placing the precipitate in the oven and drying to obtain multilayer graphene.