Removal of Ni(Ⅱ)from strongly acidic wastewater by chelating precipitation and recovery of NiO from the precipitates

• 作者: Xin Yang Xianjia Peng Linghao Kong Xingyun Hu
• 来源期刊: 环境科学学报（英文版）
• 年，卷（期）: 2021,（6）
• 页码范围: 365-375
• 页数: 11页
• 语种: 英文

摘要

Strongly acidic wastewater produced in nonferrous metal smelting industries often con-tains high concentrations of Ni(Ⅱ),which is a valuable metal.In this study,the precipitation of Ni(Ⅱ)from strongly acidic wastewater using sodium dimethyldithiocarbamate(DDTC)as the precipitant was evaluated.The effects of various factors on precipitation were in-vestigated,and the precipitation mechanism was also identified.Finally,the nickel in the precipitates was recovered following a pyrometallurgical method.The results show that,under optimised conditions(DDTC:Ni(Ⅱ)molar ratio = 4∶1;temperature = 25℃),the Ni(Ⅱ)removal efficiency reached 99.3％after 10 min.In strongly acidic wastewater,the dithiocar-bamate group of DDTC can react with Ni(Ⅱ)to form DDTC-Ni precipitates.Further recovery experiments revealed that high-purity NiO can be obtained by the calcination of DDTC-Ni precipitates,with the nickel recovery efficiency reaching 98.2％.The gas released during the calcination process was composed of NO2,CS2,H2O,CO2,and SO2.These results provide a basis for an effective Ni(Ⅱ)recovery method from strongly acidic wastewater.