Research on Environmental Impacts of Multi-silicon Wafer Based on Life Cycle Assessment

The life cycle assessment (LCA) approach was used to examine the environmental impacts in the life cycle of multi-silicon wafer, based on Chinese Endpoint Damage Model (CEDM). The data for the mass, energy fluxes and environmental emissions were obtained from site investigations and questionnaires. It showed that from the end-point of environmental impacts, the damage to human health presented the largest contribution to life cycle environmental impacts of multi-silicon wafer, which accounted for 70.21% of the total environmental impacts. However, the damage to depletion of resources and ecosystem quality was 26.22% and 3.51%, respectively. From the point of environmental factors, solar-grade poly-silicon consumption was the highest of all, accounting for 70.83%, followed by electric power consumption, silicon carbide and polyethylene glycol consumption, accounted for 19.44% and 7.62%, respectively. The environmental impacts of emission from cut process only accounted for 0.07% of whole life cycle environmental impacts. The first measure to reduce environmental impacts should be decrease in raw material consumption, and secondly reduction in energy saving and waste recycling. Compared with the average level in Europe, the environmental impacts in China were slightly higher, which was caused by raw material (solar-grade poly-silicon).