A METHOD FOR PRODUCING AN ALUMINIUM-ZIRCONIUM MASTER ALLOY (VARIANTS)

摘要

The invention relates to non-ferrous metallurgy and can be used for producing aluminium based alloys. The aluminium-zirconium master alloy is produced by aluminothermic reduction of zirconium from compounds thereof in a molten metal halide medium. Zirconium is reduced from the fluoride or oxide thereof, as well as from fluorozirconate or fluorozirconate oxide of alkali metal or alkaline earth metal in the presence of potassium chloride, sodium fluoride and aluminium fluoride, which are either introduced into the melt or formed in the aluminothermic process. The process temperature is 850-1150°C. The reduction is conducted under a layer of chloride cover flux comprising potassium chloride and sodium chloride in the following component ratio in the mixture by weight (%): potassium chloride 42-45, sodium chloride - the remainder. The melt is maintained for 15-30 minutes and then cast in ingots. The resulting master alloy ingots have a uniform structure with sizes of intermetallic compounds of up to 15-30 mum. Irrecoverable losses of zirconium are reduced to 7-9%, and the environmental characteristics of the process are improved. Aluminium alloys produced with the use of the claimed master alloy are characterised by a high quality while the quantity of the used master alloy is reduced.