METHOD OF PRODUCING THERMALLY EXPANDED GRAPHITE AND FOIL BASED THEREON Russian patent published in 2013 - IPC C01B31/04 C04B35/536 

FIELD: chemistry.

SUBSTANCE: invention can be used in making sealing, heat-insulating and electroconductive articles. At step (a), intercalated graphite compounds are obtained by reacting graphite with concentrated nitric acid; at step (b) excess nitric acid on the surface of the obtained intercalated compounds is neutralised in conditions which essentially ensure constancy of phase composition thereof by treatment with at least one reagent selected from a group comprising anhydrous carbonic acid derivatives; at step (c) the treated graphite compounds are heated in thermal shock conditions to 400-1400°C to obtain thermally expanded graphite. The anhydrous carbonic acid derivatives are carbamide, ammonium carbonate or ammonium bicarbonate. At steps (a) and (b), the following ratios are maintained, pts.wt: M_g:M_HNO3:M_r=1:(0.4-0.8):(0.1-0.3), where M_g is the mass of graphite, M_HNO3 is the mass of nitric acid, M_r is the mass of reagent. The obtained graphite foam has packed density of 1.1-1.5 g/l and the foil made therefrom has strength of 8-13 MPa and elasticity of 12-18%. Said products are obtained using a simple and low power consumption method.

EFFECT: reduced amount of reagents.

9 cl, 1 tbl