Metal distillation method utilizing double vaporization

A method for separating a certain metal from a mixture of said certain metal with other elements which have lower vapor pressure values than said certain metal, comprising the steps of:

• (a) heating said mixture in order to partially vaporize said certain metal and said other elements with the result that the composition of the gas mixture generated by said heating is shifted to a mixture substantially enriched in said certain metal as a result of the differences in vapor pressure values of the elements which have been vaporized;
• (b) adiabatically expanding said gas mixture resulting in said gas mixture being substantially liquified;
• (c) allowing the liquified gas to vaporize principally by the heat of the liquified gas, the result of which is that the composition of the gas thus generated is further enriched in the amount of said certain metal because of the differences in vapor pressure value of the components of said liquified gas and also because the composition of the liquified gas is changed from that of the mixture which is originally heated;
• and
• (d) collecting the gas generated by the vaporization process of step (c) thereby permitting recovery of said certain metal.