Chemical changes in concentrated, acidic, metal-bearing wastewaters when treated with lime

Lime neutralization of acidic wastewaters can prove to be an effective treatment process provided sufficient lime is added. The chemical changes that occur in the system are extensive and varied. Precipitation is predominant with complexation, oxidation, and adsorption playing major roles. Total chemical analyses have identified the chemical changes, and controlled laboratory simulations have identified the relative importance of the physical-chemical processes. Rxchange of oxygen and carbon dioxide are discussed, and optimum lime addition rates are predicted by thermodynamic computer simulation.