METHOD OF COAL PREPARATION TO OBTAIN HUMATES Russian patent published in 2017 - IPC C05F11/02 C05F11/00 

FIELD: agriculture.

SUBSTANCE: method for coal preparation to obtain humates includes cleaning it from mechanical impurities and grinding. Coal is crushed to size less 2 mm, checked for the content of toxic metals, including lead, arsenic, cadmium, mercury, and if at least one of them is detected with concentrations exceeding the maximum concentration limit (MCL), the coal is introduced into a 10-20% aqueous solution of hydrochloric acid with a temperature of 80-95°C and kept stirred for 4-8 hours. Then, it is washed in pure fresh water with a temperature of 80-95°C, rechecked for toxic metals and if the concentration of at least one of the toxic metals does not fall below the MCL, the acid treatment and washing processes are repeated in said modes in order to reduce the content of all toxic metals below the MCL.

EFFECT: invention allows to lower the content of toxic metals below the MCL, which are in the natural coal intended for the production of alkali metal humates from it, and thereby to ensure suitability of the product obtained for human consumption.

2 cl, 2 ex