RECOVERY OF MERCURY AND LEAD FROM WASTEWATER BY SULFIDE PRECIPITATION-FLOTATION

摘要

The wastewater containing Hg~(2+) and Pb~(2+) does great harm to the environment and human bodies. Traditional wastewater treatment cannot fundamentally put a stop to heavy metals pollution for producing secondary pollution. In this paper, Hg~(2+) and Pb~(2+) in wastewater were removed and recovered by sulfide precipitation-flotation. Sodium sulfide was used as precipitant and butyl ammonium aerofloat was used as collector. Results indicated that Hg~(2+) and Pb~(2+) could be reduce to less than 0.03mg/L and 0.16mg/L respectively by both coprecipitation-floatation and fractional precipitation-floatation. In these two methods, fractional precipitation flotation could not only remove Hg~(2+) and Pb~(2+) from wastewater, but also could recover mercury and lead effectively. The infrared spectrograms showed that the adsorption between butyl ammonium aerofloat and mercury precipitate or lead precipitate is chemisorption.