`Environmental Impact Analysis of Blast Furnace Slag Applied to Ordinary Portland Cement Production

This study was conducted based on the ISO 14040/14044 standards to analyze the environmental impact caused by blast furnace slag utilization for ordinary Portland cement production in typical plants in Beijing. In addition, sensitivity analysis of resource consumption, transport distance, the allocation methods and life cycle impact assessment model were discussed in detail. The results showed that global warming potential and acidification potential were the most significant environmental impacts resulted by slag-based cement production, accounting for 58.5% and 21.7% of the total environmental impact, respectively. Moreover, the cement production and energy generation phases accounted for 66.6% and 29.6% of total environmental loads of slag-based cement from cradle to gate, respectively. Sensitivity analysis showed that the comprehensive environmental impact of slag-based cement was sensitive to the consumption of limestone and energy, as well as the allocation methods and life cycle impact assessment model; but was insensitive to the consumption and transport distance of blast furnace slag. Compared with traditional Portland cement, except for the approximately 9% increase of human toxicity potential, the other impacts of slag-based cement decreased to a certain extent. In particular, abiotic depletion potential and land use potential significantly reduced by 72% and 41%, respectively. Therefore, producing cement with blast furnace slag would slightly increase electricity consumption, but significantly improve the benefits of land resource and materials conservation and significantly decrease the comprehensive environmental impact of cement.