| 摘要 |
<p>1533704 Recovery of Al BRITISH ALUMINIUM CO Ltd 14 Nov 1975 [18 Nov 1974 6 Oct 1975] 49778/74 and 40791/75 Heading C7D Aluminium (including Al-base alloys) is recovered from aluminous material, comprising furnace skim, dross, metal residues or finely-divided scrap, by feeding it into a liquid salt flux layer floating on a body of liquid A1 and agitating to allow the A1 to pass into the body. The body of liquid Al may be held in a side-well 22 of a reverberatory melting furnace 21 such that the body of A1 23 is in communication with the molten Al 24 by channels 25 in the baffle wall 26. The skim 28 is raked on to the flux layer 27. The flux is based on the chlorides of the alkali and alkaline earth metals (inc Mg), and may also contain one or more corresponding fluorides. Suitable fluxes contain NaCl and KCl either in equal weight proportions or in eutectic proportions and may include 0-5% Caf 2 , 0-25% NaF and 0-20% MgCl 2 . In other embodiments, the treatment may be carried out in a heated crucible (Fig. I not shown), in a mobile refractorylined box (Fig. 5, not shown), in a crucible held partially submerged in an Al melt and being in communication with the melt by means of holes in the bottom and side-wall, the agitation being effected by a tangential jet of liquid Al into the crucible (Figs. 6-9, not shown) and in a refractory ring movable over the surface of an Al melt relative to an Al jet (Figs. 10, 11, not shown).</p> |
