| 摘要 |
<p>The present invention relates to a process for purifying metals, such as aluminum, by segregation, wherein, by controlled cooling in the upper part of a volume of liquid metal to be purified, which is contained in a crucible and disposed in a furnace, small crystals are caused to form, the crystals falling towards the bottom of the container under the force of gravity. The small crystals are compacted so as to cause the formation of a compact layer of large purified crystals. This process is distinguished from the known processes in that, to enhance the purification effect, the thermal flux is so adjusted as to completely and progressively re-melt the lower part of the mass of large crystals which are formed, with the re-melting action being propagated upwardly so as permanently to maintain a layer of large crystals which separates the re-melted liquid entirely disposed in the lower part from the remaining mother liquor. That process makes it possible to attain extremely high levels of purification, in relation to very high fractions of the initial mass of aluminum which is to be purified. The process can be applied to metals such as aluminum, lead, zinc, magnesium and silicon containing eutectic impurities in hypoeutectic amounts.</p> |
