Abstract: Alkaline earth silicate solids with a surface area in the range of about 0.1-1000 m.sup.2 /g are used to remove Ag, Pb, Zn, Ni, and Cr (III) metal ions from contaminated waste waters. The foregoing metal ions are removed from the contaminated waste waters by a process involving the steps of contacting the contaminated waste waters at a pH in the range of 4 to 6 with the alkaline earth silicate solid and thereafter filtering the alkaline earth silicate solid from the contaminated waste waters to remove the metal ions.