RECOVERY OF METALS AND ACIDS FROM EXHAUSTED PICKLING SOLUTIONS AND/OR NEUTRALIZATION SLUDGE

摘要

A process of complete recovery of metals and acids from solutions and sludge polluted with metals coming from stainless steel works is disclosed. Volatile acids are recovered from exhausted pickling solutions through distillation in presence of sulphuric acid while metals are separately recovered in the elementary form or as hydroxides and salts. The treatment is also applied to sludge produced by neutralization of steel works waste, even when said sludge is already stored in dump sites, where a previous redissolution in an acidic medium is required.