Process and apparatus for producing high purity metals by enhanced purification

摘要

In a purification apparatus comprising a vertical stack of a feed heating zone having the feed crucible 1, a condensation zone having a plurality of condensation vapor passage plates 5, a solidification zone having a solidification crucible 2 and an entrapment/solidification zone having a plurality of entrapment/solidification vapor passage plates 7, a feed metal, preferably with a purity of at least 3N, is charged into the feed crucible 1 in a vacuum atmosphere, preferably at no more than 13 Pa (10<-1> Torr), with the feed crucible 1 and the condensation vapor passage plates 5 being heated at controlled temperatures to generate the vapor of the metal in the feed heating zone; part of the metal vapor is condensed to form a molten condensate which is returned into the feed crucible 1, thereby ; the process solidifying the high-purity metal in the solidification zone; the solidified metal has a purity of at least 6N and contains Cl, F and S in a respective amount of no more than 0.1 ppm with a total impurity content of no more than 1 ppm.