METHOD OF PRODUCING GRAPHENE OXIDE FROM KISH GRAPHITE Russian patent published in 2020 - IPC C01B32/198 C09K5/10 B82Y40/00 

FIELD: chemical industry; metallurgical industry.

SUBSTANCE: invention can be used in production of steel, aluminum, copper or copper alloys, iron, titanium, cobalt, nickel, metal composites, coatings and cooling agents. At first A) graphite is obtained. Then B) is pre-processed, including consecutive sub-stages: i. screening, ii. flotation, iii. acid leaching, iv. optional washing and drying. In sub-step i. Graphite is classified by size and a fraction with particle size of 50–300 mcm is selected, which is directed to sub-step ii. In sub-step iii. acid is added so that weight ratio of acid to Kish-graphite is between 0.25 and 1.0. Preliminarily treated Kish-graphite is oxidized at step C) in order to obtain graphene oxide. Step C) includes sub-steps: i. preparation of mixture, containing pre-treated Kish-graphite, acid and optionally sodium nitrate, its holding at temperature below 5 °C, ii. adding an oxidising substance to said mixture to achieve a given level of oxidation, iii. adding oxidation stopping reagent, iv. optionally recovering obtained graphite oxide, v. optional flushing, vi. optional drying and vii. delamination into graphene oxide. At stages B.iii) and Ci), acid is selected from hydrochloric, phosphoric, sulfuric, nitric or their mixtures. Oxidising substance is selected from potassium permanganate, H₂O₂, O₃, H₂S₂O₈, H₂SO₅, KNO₃, NaClO or mixtures thereof. Reagent which stops oxidation is selected from an acid, non-ionized or deionised water, H₂O₂ or mixtures thereof. Centrifugation, decantation or filtration is used at stage C.iv). Stages C.iv) and Cv) are performed at least twice independently. Thermal delamination or ultrasound is used at stage C.vii.).

EFFECT: invention improves ecology due to recycling metallurgy wastes and obtains high-quality graphene oxide therefrom.

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