METHOD FOR TREATMENT OF POTLINING RESIDUE FROM PRIMARY ALUMINIUM SMELTERS

摘要

Method for treatment of spent potlining from aluminium reduction cells included the refractory material in order to transfer the spent potlining to a form in which it can be used as a filler or as a raw material. The spent potlining is crushed and supplied lo a closed electrothermic smelting furnace optionally together with a SiO2 source. wherein the spent potlining is melted at a temperature between 1300 and 1750.degree.C. An oxidation agent is supplied to the furnace in order to oxidize carbon and other oxidizable components contained in the spent potlining such as metals, carbides and nitrides. Further, a source of calcium oxide is supplied to the smelting furnace in an amount necessary to react with all fluoride present to form CaF2 and to form a calcium aluminate or calcium aluminate silicate slag containing CaF2 which slag is liquid at the bath temperature in the furnace, and that the calcium aluminate orcalcium aluminate silicate slag and optionally a metal phase are tapped from thefurnace and cooled to blocks or granules.