METHOD OF CLEANING ULTRA-DISPERSED DIAMONDS Russian patent published in 2010 - IPC C01B31/06 

FIELD: chemistry.

SUBSTANCE: diamond-containing mixture is separated from mechanical impurities, demineralised from fine inorganic impurities with hydrochloric acid and washed. The obtained filtrate is analysed for presence of impurities using potassium ferrocyanide. The mixture is dried and treated with concentrated LiOH solution in the presence of ammonia solution with mass ratio of dry reagents LiOH/mixture equal to 0.8/1.0. A sample of the dried mixture with LiOH is heated in a muffle furnace from 20 to 500°C until formation of molten LiOH in the mixture. The obtained molten mass is cooled to room temperature, washed with water until attaining pH=7 and dried.

EFFECT: more efficient removal of impurities from ultra-dispersed diamonds using a short and more reliable method.

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