Process for dissolving a metal and implementation for conditioning said metal in a geopolymer.

The present invention relates to a method for preparing a medium comprising at least one metal hydroxide of placing a metal in an oxidation state of zero in contact with a medium comprising at least one molten salt of the hydroxide type, in the presence of a more oxidizing element that said metal to an oxidation state of zero, whereby a medium comprising at least one metal hydroxide is obtained. The present invention relates to the use of said medium to prepare an activation solution for wrapping said metal in a geopolymer.