Life Cycle Analysis on Carbon Emission Reduction and Energy Saving by Using Slag as Alternative Materials in Cement Production

Abstract

The carbon emission and energy consumption of using slag as a secondary raw material in cement production was quantified and analyzed in this study. Moreover, the carbon emission reduction and energy saving potential of slag-based cement (SBC) production were identified based on the comparative analysis between SBC and traditional Portland cement (TPC). The results showed that the carbon emission of SBC is about 6.73%, which was lower than that of TPC. Compared with TPC, the energy consumption of SBC is slightly increased by 2.05%. In addition, it was found that the combustion of coal and the power generation were the main sources for carbon emission in the life cycle of slag utilization, which account for 83.39% and 10.16% of the total carbon emission. Therefore, reducing the consumption of energy and increasing the recovery rate of waste heat in cement production were the most effective methods to improve the environmental performance of SBC. In addition, the improvement potential analysis was carried out for SBC. The results indicated that if the recovery rate of waste heat could reach to that of the international advanced level (15.6%), the carbon emission and energy consumption of SBC would be reduced by about 2.20% and 5.71%, respectively. If the proportion of renewable energy utilizationin power generation increased to that of the average international level, the carbon emission and energy consumption of SBC would be declined by 5.26% and 9.35% respectively.