Low carbon measures for cement plant – a review

Cement manufacturing is an energy and carbon-intensive industry. The cement industry contributes approximately 5% of the global man-made carbon dioxide (CO2) emissions and is thus becoming the second largest CO2 contributor in industry after power plants. A wide range of options are available to considerably reduce CO2 emissions. This paper reviewed major point sources of CO2 emissions at all stages of cement manufacturing, including (1) raw material preparation (grinding and transportation), (2) clinker production and the combustion of fuels in the kiln and (3) the production of cement final product (milling, blending, mixing, packaging and transportation. Various CO2 mitigation strategies are subsequently discussed, including (1) energy efficiency improvements; (2) waste heat recovery; (3) the substitution of fossil fuel with renewable energy; (4) the production of low carbon cement by replacing ordinary Portland cement with alternative materials, i.e., geo-polymers, blast furnace slag, coal fly ash, and natural pozzolanic materials; and (5) carbon capture and storage. Although reviewed CO2 mitigation measures are indeed beneficial to the environment, however, they are also bounded by some limitations. The limitations and selection of CO2 mitigation measure are also outlined in this paper.