TREATMENT METHOD OF WASTE LINING FROM ELECTROLYTIC MOLTEN ALUMINIUM Russian patent published in 2013 - IPC F23G5/20 

FIELD: metallurgy.

SUBSTANCE: treatment method of waste lining from electrolytic molten aluminium involves heating of waste lining in a rotating calcining furnace with addition of solid oxidising and gasifying compounds; at that, as an oxidising compound, calcium carbonate is used, accumulation of gases leaving the rotating furnace, removal of fluorides from them, cooling of heated products and their grinding. Prior to heating, waste lining is crushed to the particle size of 15-20 mm, and then, finally crushed to the particle size of 0.35-1.5 mm by adding an oxidising compound, and namely calcium oxide, and active additives, particularly CaSO₄, FeO in the quantity of 0.23-0.35 wt % of the waste lining weight. Oxygen is used as a gasifying compound. Heating is performed with oxygen blasting to the furnace volume, at the furnace rotation speed of 1.5-2.5 m/min in three stages; at that, at the first stage, heating up to 400°C is performed during 40-60 minutes; at the second stage, the furnace temperature is increased up to 400 to 800°C and exposed during 60-80 minutes; at the third stage, the furnace temperature is increased up to 800 to 1000°C and exposed during 60-80 minutes; at that, when changing over from one stage to another one, reversal of the rotating calcining furnace is changed.

EFFECT: increasing removal degree of fluorides and cyanides.

3 cl, 1 dwg, 2 tbl