PROCESS FOR SEPARATION OF HEAVY METALS FROM RESIDUES BY USE OF ETHYLENE-DIAMINE DISUCCINIC ACID (EDDS) COMPLEXANT

摘要

A process for precipitating heavy metal ions from an aqueous solution of a chelated heavy metal ion/EDDS (ethylene diamine disuccinic acid) complex by addition of a second metallic compound leading to a substitution reaction. Preferably the isomer of EDDS used is [S.S] EDDS, and the added solution consists of CuSO 4 . The chelated complex solution may be formed by contacting active aqueous EDDS with contaminated soil. Precipitation is affected by the addition of an alkaline material, preferably a hydroxide salt of calcium, magnesium, potassium or more preferably sodium, but may be a carbonate or phosphate salt of these metals (or a mixture thereof). The heavy metals may be Ca, Al, Mg, Cd, Hg, Zn, Pb, Ni, Cr, Co or mixtures thereof.