Recovering heavy metal cpds. from dilute aq. solns. - by adding a basic magnesium cpd. and separating the ppte.

摘要

Process for recovering heavy metal components from dilute aq. solns. contg. heavy metal salts comprises precipitating the heavy metal cpd. as the hydroxide by adding a basic Mg cpd. to the dil. aq. soln., and recovering the ppte. formed. The heavy metal cpd. may be e.g. of Fe, Cr, Ti, Cu, Zr, Ni, Sn, Co, Cd or Mn and the soln. is neutralised to pH 3.0-10.0 with a Mg cpd. such as Mg(OH)2 or lightly calcined magnesia. Process is simple to operate, can be used economically on an industrial scale, and gives good removal of heavy metal cpds. e.g. from effluent. Typical effluents are obtd from plating baths, viscose mfr., fibre prodn., metal treatments and pigment mfr.