The scope considered for CO2 emission from cement production in Gong (2004) includes AMG-458 direct impacts from raw material exploitation, raw meal preparation, clinker, grinding, packing and transport process and indirect impacts from electric power production and coal production related. The emission factor of cement production depends on the production skills, though skills of shaft kiln and rotary kiln occupied the major position in about 2004, Gong (2004) selected the skill of new dry process for study. Xu (2013) studied the status of cement industry in China, indicated that the technique of new dry process is dominating in developed countries, and suggested this process will soon replace the methods of “shaft kiln” and “wet process kiln” in China.
Wang (2007) also analyzed the energy consumption and emissions of steel and cement production based on life cycle assessment. Table 1 summarized the study scopes and results by different authors for CO2 emission factors during steel and cement production.