ИСТИНА

FIELD: chemical analysis. SUBSTANCE: starting product is treated with reagent (concentrated sulfuric acid + K2Cr2O7, concentrated sulfuric acid + (NH4)2S2O8, concentrated sulfuric acid + KNO3) at room temperature for the course of 10-30 min. Compound of introduction into graphite formed in this case is transformed by thermal treatment at 500-600 C into expanded graphite. Selective oxidation of expanded graphite is conducted in process of alkaline alloying of sample which is also performed to disintegrate rock. After this isolated crystals of diamonds are burnt at 1000 C in current of oxygen and content of carbon is determined by potentiometric titration. EFFECT: expanded application field, improved accuracy of analysis. 3 cl, 1 tbl