▎ 摘　　要

NOVELTY - Graphene oxide is manufactured from kish graphite by (A) providing kish graphite; (B) pre-treating kish graphite by (i) classifying kish graphite by size according to kish graphite with size of less than or equal to 50 mu m, kish graphite with size of greater than or equal to 50 mu m in which fraction of kish graphite with size less than or equal to 50 mu m is removed, (ii) floating kish graphite with size of greater than or equal to 50 mu m, and (iii) adding acid so that ratio in weight (acid amount)/(kish graphite amount) is 0.25-1; and (C) oxidizing pre-treated kish-graphite by (i) preparing mixture comprising pre-treated kish graphite, acid, and ammonium nitrate (NH4NO3) and keeping mixture at less than or equal to 5 degrees C, (ii) adding oxidizing agent into the mixture, (iii) adding chemical element to stop oxidation reaction after targeted level of oxidation is reached, (iv) optionally, separating graphite oxide from mixture, and (v) exfoliating graphite oxide into graphene oxide. USE - Manufacture of graphene oxide from kish graphite. ADVANTAGE - The method allows for the production of graphene oxide having good quality from high purity pre-treated kish graphite. The kish graphite obtained after step (B) has a purity of greater than or equal to 90%. Moreover, the method including the pre-treatment of kish graphite and the oxidation into graphene oxide is easy to implement at industrial scale and is less polluting than methods of the prior art, in particular the one using sodium nitrate (NaNO3). On one hand, no toxic gasses produced during the oxidation are nitrogen (N2), oxygen (O2), and water (H2O) with ammonium nitrate (NH4NO3) instead of toxic gasses with NaNO3. On the other hand, the amount of gasses produced with NH4NO3 is higher than the one produced with NaNO3. As a result, more gasses are intercalated between the kish graphite layers so that during the oxidation step (C.ii), potassium permanganate (KMnO4) can easily navigate between the kish graphite layers and oxidize them. It results in a significant reduction of the oxidation time compared to NaNO3. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for graphene oxide comprising greater than or equal to 45 wt.% oxygen functional groups and having average lateral size of 5-50 mu m comprising greater than or equal to 1 layer sheet.