CO₂ NEUTRALIZES ZINC WASTEWATER

In the neutralization of wastewater from zinc extraction operations, liquid carbon dioxide plays a key role. The wastewater has a very high pH ranging from ten to eleven, which must be lowered to the neutral range before discharge.

Sulfuric acid was often used for this purpose in the past, but not without serious drawbacks: it requires elaborate safety precautions, its addition is difficult to control with precision, and the resulting wastewater is salt-laden and corrosive. Liquid carbon dioxide offers a more efficient and safer alternative here.