Stabilization of heavy metals in solid residues and soils involves application of magnesium oxide of low content

摘要

Stabilization of heavy metals contained in solid residues and soils involves application of magnesium oxide of low content. The residues and soils involved have a pH less than 8 and a high content of heavy metals. The use of magnesium oxide situates the pH of the mixture at levels at which the solubility of the heavy metals is minimal. The quantity of magnesium oxide used depends on the nature of each residue, and this is optimized by using a lixiviation test on various proportions of the stabilizing residue. The addition of an excess of magnesium oxide maintains the pH of the stabilized residue at the optimal values of solubility of the heavy metals. The addition of the necessary quantities of water to the residue which has been stabilized permits its hardening with the passage of time, thus acquiring a consistency which facilitates ultimate manipulation.