Patent ID: 7128006

Claim:
A process for rendering inert an ash originating from the incineration of municipal waste, wherein the ash is subjected successively to treatment with a water-soluble phosphate in the presence of water and to calcination, comprising treating the phosphate under conditions adjusted to crystallize hydroxyapatite and/or whitlockite in an amount sufficient to absorb substantially all of the heavy metals of the ash, wherein said treating the phosphate under conditions adjusted to crystallize hydroxyapatite and/or whitlockite comprises adjusting the water-soluble phosphate concentration so as to form crystallized hydroxyapatite and/or whitlockite in a sufficient amount to absorb substantially all of the heavy metals of the ash, and further comprising adjusting calcium concentration so as to form crystallized hydroxyapatite and/or whitlockite in a sufficient amount to absorb substantially all of the heavy metals of the ash.