Life-cycle environmental impact analysis of a typical cement production chain

Abstract

Cement is one of the three main construction materials, which provides support for other related industries and fuels the economic growth. However, cement production is also a high-polluting sector. In this study, a life-cycle environmental assessment was performed for a typical new suspension preheater dry process (NSP) cement production in China. A comparison of the life cycle environmental impact of best available technologies was also conducted by setting a series of scenarios so as to find the most promising alternative in reducing environmental impacts. The results suggest that although direct calcination is the largest contributor of environmental emissions in the cement production system, indirect sections, particularly the downstream grinding section, play an important role in terms of environmental impact, which should be considered as the control point in achieving energy saving and emission reduction goal. Comparing the environmental performance of raw material and fuel substitution alternatives and best available technologies, the results of scenario analysis reveals that environmental benefits of carbide slag and the mixture of carbide slag and limestone slag as raw material substitutions is not prominent as it induces extra environmental costs that offset the environmental benefits from reduced limestone usage. Corn straw as coal substitution and heat recovery and cogeneration are found to be promising ways to achieve environmental mitigation with a notable environmental benefit for cement production. The prevailing NSP kiln technology is more environmental beneficial compared with shaft kiln technology.