GB889247A - Method and apparatus for recovering metal from scrap - Google Patents

Abstract

889,247. Recovering aluminium and aluminium alloys from scrap. KAISER ALUMINIUM & CHEMICAL CORPORATION. May 11, 1959. No. 16111/59. Class 82(1). [Also in Group XII] A method of melting aluminium metal or alloy, e.g. scrap, comprises the steps of having a body of fused salt 7 in a first chamber 3 consisting of a mixture of Na Cl, KC1 and a fluoride constituent less dense than the metal or alloy and maintained above 1300‹F., continuous withdrawal of the salt therefrom for introduction into a second chamber 4 so as to give intimate mixing with metal or alloy therein, and passing the mixture into a third chamber 5 below the surface of the salt in chambers 4 and 5, wherein substantially all of the metal or alloy fuses and settles to the bottom of chamber 5, the fused salt rising to the surface for continuous withdrawal to the chamber 3. The Na Cl and KCl may be 15 to 65% and 85 to 35% in relation to each other, the fluoride being 2À5 to 5% of the total fused salt. The apparatus used comprises a heatable salt-melting receptacle for the chamber 3 (Fig. 3) and a heatable metal-melting reinto the with a partition 55 to divide it ceptacle 2 chambers 4 and 5 (Fig. 4) above a passage 8, a motor-driven pump 6 in a zone 17 and conduit 11 for the transfer of fused salt from the chamber 3 to the open chamber 4, charged by a shoot 34 (Fig. 2), fused salt being returned to the former from the chamber 5 through a further conduit 9 and trough 51. Molten metal is removed, after tilting the receptacle about trunnions to decant fused salt away, through a tap hole 48 and a skim of aluminium oxide and fused salt a layer in the chamber 5 between the pure salt on the surface and the molten metal may be removed by another suitable opening on tilting the receptacle 2 about other trunnions thereafter.