Application of Iron Powder Reduction Method to Remove Heavy Metals in Waste Pickling Acid

Abstract

The removal of heavy metals in waste pickling acid by iron powder reduction was studied. The effects of reaction time, reaction temperature and dosage of iron powder on the removal efficiency of Zn, Cr, Ni and Pb in waste pickling acid were investigated. The results showed that, the removal rate of Cr tended to be stable after 2 h of reaction under magnetic stirring. After 4 hours, the removal rate of Zn,Ni and Pb tended to be stable. The temperature was increased from 20°C to 90 °C, the removal rates of Ni and Pb could be increased by 9.09% and 11.6%, while the removal rates of Zn and Cr were only increased by 1.15% and 2.85%; Increasing the dosage of iron powder was beneficial to the removal of heavy metals in waste pickling acid, and the combined amount of free acid in the waste acid would affect the removal efficiency of heavy metals. The research results had important guiding significance for the practical application of iron powder reduction method in the heavy metal purification project of waste pickling acid.