METHOD OF PRODUCING HUMATE-CONTAINING COMPOUNDS FROM BROWN COAL Russian patent published in 2005 - IPC

FIELD: coal-chemical products.

SUBSTANCE: weathered vitrinite brown coals from Baga-Nursk coal field having ash level 36-48% and moisture 20% are ground to granule size 0.5-0.9 mm. Resulting powder us sulfurized for 6-8 h with 98% sulfuric acid at 60-80°С and coal-to-acid weight ratio from 1:3 to 2:3. Sulfurized coal is neutralized and treated with 10-15% sodium hydroxide aqueous solution at weight ratio of alkali solution to initial coal (10-15):1 to form water-soluble sodium sulfohumate, after which water-soluble residual coal is separated by centrifugation. Centrifugate is mixed with 10-15% aqueous hydrochloric acid at volume ratio (10-15):6 to form precipitate, which is allowed to settle into compact form during 40-60 min. After decantation of liquid phase, solid residue is partially dried at 40-60°С until pasty mass is obtained.

EFFECT: increased content of tanning substances in humate-containing compounds and enabled utilization of oxidized brown coal in open-cut production of brown coals.

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