METHOD OF PRODUCING HYDROGEN FLUORIDE FROM ALUMINIUM PRODUCTION WASTES Russian patent published in 2014 - IPC C01B7/19 

FIELD: chemistry.

SUBSTANCE: method of producing hydrogen fluoride from aluminium production wastes includes sulphuric acid decomposition of cryolite-containing wastes. The aluminium production wastes used are electric filter dust. The wastes are first ground to particle size of 0.2 mm, placed on trays in a layer with height of not more than 0.5 cm and fired at 800-850°C in hearth furnaces. Sulphuric acid decomposition of the concentrate obtained after burning the wastes is carried out at temperature of 240-260°C.

EFFECT: invention reduces consumption of sulphuric acid and increases output of hydrogen fluoride.

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