Patent ID: 7955414

Claim:
Method for the purification and separation of purified metal from a metal mother liquid having a specific density and comprising one or more foreign element(s), the method comprising the steps of: providing in a column device a starting material comprising metal crystals and a metal mother liquid comprising at least one foreign element; applying a temperature difference between a relatively hot zone at the upper end of the column and a relatively cool zone at the lower end of the column; a separation step wherein at least a part of the metal crystals are separated from the metal mother liquid by rising of the metal crystals to the upper surface of the metal mother liquid; and a further separation step wherein purified liquid metal or metal crystals floating at the upper surface of the metal mother liquid is discharged from the column device, wherein metal crystals rise from the metal mother liquid by adjusting the specific density of the metal mother liquid to a value of more than the specific density of the purified liquid metal and of more than the metal crystals and wherein the specific density of the metal mother liquid is adjusted to said value by the addition of a metal.