▎ 摘　　要

NOVELTY - Manufacturing graphene oxide from kish graphite, comprises: (A) provision of kish graphite; (B) pre-treatment step of the kish graphite comprising (i) sieving step where the kish graphite is classified by (a) kish graphite having a size below 50 mu m, and (b) kish graphite having a size of greater than or equal to 50 mu m, the fraction (a) of kish graphite having a size of below 50 mu m being removed, (ii) flotation step with the fraction (b) of kish graphite having a size of greater than or equal to 50 mu m and (iii) an acid leaching step where an acid is added so that the ratio in weight (acid amount)/(kish graphite amount) is 0.25-1; and (C) an oxidation step of the pretreated kish-graphite obtained after the step (B) in order to obtain graphene oxide. USE - The method is useful for manufacturing graphene oxide from kish graphite, where the graphene oxide is useful as a cooling reagent for deposition on a metallic substrate (all claimed). ADVANTAGE - The method provides graphene oxide that improve corrosion resistance of a metallic substrate. DETAILED DESCRIPTION - Manufacturing graphene oxide from kish graphite, comprises: (A) provision of kish graphite; (B) pre-treatment step of the kish graphite comprising (i) sieving step where the kish graphite is classified by (a) kish graphite having a size below 50 mu m, and (b) kish graphite having a size of greater than or equal to 50 mu m, the fraction (a) of kish graphite having a size of below 50 mu m being removed, (ii) flotation step with the fraction (b) of kish graphite having a size of greater than or equal to 50 mu m and (iii) an acid leaching step where an acid is added so that the ratio in weight (acid amount)/(kish graphite amount) is 0.25-1; and (C) an oxidation step of the pretreated kish-graphite obtained after the step (B) in order to obtain graphene oxide comprising (i) preparation of a mixture comprising the pretreated kish-graphite, an acid and ammonium nitrate, the mixture being kept at a temperature of below 5 degrees C, (ii) addition of an oxidizing agent into the mixture obtained in step C.(i), (iii) after the targeted level of oxidation is reached, the addition of an element to stop the oxidation reaction, (iv) optionally, the separation of graphite oxide from the mixture obtained in step C.(iii) and (v) exfoliation of graphite oxide into graphene oxide. An INDEPENDENT CLAIM is also included for graphene oxide comprising at least 45 wt.% of oxygen functional groups and having an average lateral size of 5-50 mu m comprising at least one layer sheet obtainable from the method.