Method for treatment of potlining residue from primary aluminium smelters

摘要

A method for the treatment of spent potlining from aluminium reduction cells including refractory material in order to transform the spent potlining to a condition in which it can be used as a filler or as a raw materia. The spent potlining is crushed and supplied to a closed electrothermic smelting furnace, optionally together with a SiO₂ source, in which the spent potlining is melted at a temperature between 1300 and 1750°C. An oxidation agent is supplied to the furnace in order to oxidise carbon and other oxidisable components contained in the spent potlining such as metals, carbides and nitrides. A source of calcium oxide is also supplied to the smelting furnace in an amount necessary to react with all fluoride present to form CaF₂, which slag is liquid at the bath temperature in the furnace. The calcium aluminate or calcium aluminate silicate slag and optionally a metal phase are tapped from the furnace and cooled to blocks or granules.