The Portland Cement Association has outlined industry goals to reduce carbon emissions by adopting a three-part approach by 2020. The information is part of PCA’s 2007 Summary Report on Sustainable Manufacturing.
According to the report, the cement industry aims to reduce CO2 emissions by 10 percent below 1990 baseline levels by a) upgrading plants with state-of-the-art equipment; b) improving product formulation to reduce energy of production and minimize the use of natural resources; and c) conducting research and developing new applications for cement and concrete that improve energy efficiency and durability.
A major element of the effort is the recycling of cement kiln dust, or CKD, which is created during the third stage of manufacturing when clinker is formed. Electrostatic and bag filters capture the dust for recycling. The industry recycles more than 75 percent of cement kiln dust — nearly eight million tons each year — directly back into the cement kiln as raw material. Recycling this byproduct also reduces the need for limestone and other raw materials and helps conserve energy. Other uses for CKD include agricultural soil beneficiation and soil stabilization.