METHOD FOR REFINING AN ALUMINIUM SCRAP SMELT, AND ALUMINIUM ALLOY FROM REFINED ALUMINIUM SCRAP

摘要

A method of refining a melt of aluminium scrap material which comprises metallic aluminium and impurities including iron, in order to obtain a target iron level, comprises (i) determining the initial amounts, in % by weight, in the melt of Mn, Fe and Si, these amounts being ¢Mn0!, ¢Fe0! and ¢Si0!; and (ii) adding a quantity Mnx of Mn to the melt, so as to obtain in the melt, after the refining of the melt, a ratio .delta. given by .delta. = ¢Mn1!/¢Fe1! wherein ¢Mn1! and ¢Fe1! are the amounts in % by weight of Mn and Fe after the refining of the melt, ¢Fe1! being the desired target level of Fe and ¢Mn1! being given by ¢Mn1! = A - B * ¢Fe1! wherein 1.86 - 0.17 * ¢Si0! + 0.004 * ¢Si0!2 A 2.21 - 0.17 * ¢Si0! + 0.005 * ¢Si0!2 and 0.42 + 0.50 * exp (- 0.28 * ¢Si0!) B 0.57 + 0.50 * exp (- 0.28 * ¢Si0!), The added quantity Mnx of Mn is given by Mnx = .delta. * Fe0 - Mn0 wherein Fe0 and Mn0 are the initial quantities of Fe and Mn in the melt. Thereafter the method comprises homogenizing the melt by heating, cooling the melt and maintaining it at a super-eutectic holding temperature so that solid intermetallic compounds form, and separating the solid intermetallic compounds.