Life cycle assessment for waste acid treatment in zinc smelting
(1. China Enfi Engineering Corporation, Beijing 100038, China;
2. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
3. Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083, China;
4. National Science Library, Chinese Academy of Sciences, Beijing 100190, China;
5. University of Chinese Academy of Science, Beijing 100049, China)
2. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
3. Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083, China;
4. National Science Library, Chinese Academy of Sciences, Beijing 100190, China;
5. University of Chinese Academy of Science, Beijing 100049, China)
Abstract: Lift cycle assessment (LCA) methodology was applied to evaluating and comparing two waste acid disposal processes in zinc smelting. The results indicate that environmental impacts of gas-liquid vulcanization technologies are human toxicity, abiotic depletion potential, and global warming risk, which are mainly caused in neutralizing- evaporating-crystallization unit and electrodialysis unit. As for traditional lime neutralization method, vulcanization unit is the main factor. In this regard, the total environmental impact of traditional lime neutralization method is much higher than that of gas-liquid vulcanization technologies. Furthermore, the sensitive analysis shows that electricity and sodium sulfide (60%) are sensitive factors in two waste acid disposal technologies. In addition, the total cost of disposing a functional unit waste acid in traditional lime neutralization process is nearly 27 times that of the gas-liquid vulcanization waste acid disposal technologies.
Key words: zinc smelting; waste acid treatment; life cycle assessment; environmental impact