Waste materials co-processing in cement industry: Ecological efficiency of waste reuse

Cement is the main component of concrete, which is, in turn, the second most consumed material on earth, in addition, the cement industry is one of the most intensive energy consumptions. The modern plants often have nominal production capacity exceeding one million tons per year. To produce one ton of cement, you need the equivalent of 60–130 kg of fuel and 110 kWh of electricity. Due to the large consumption of energy, which represents over 30% of the total production cost for the cement industry, the reduction in spending on energy inputs is a major motivation for technological advances in the production process of cement. To reduce the costs of fossil fuel consumption (non-renewable source), the technique of co-processing has been employed for introducing alternative fuels as part of the manufacturing process. This technique provides a lower cost of production, introducing fuel waste from different industrial activities, besides contributing to the reduction of environmental liabilities; they generate waste when discarded in inappropriate places. It is evident that the cement industry sector is highly intensive in energy consumption, and should be considered in studies on energy planning, especially with the changes in its energy matrix, which has occurred continuously since the oil crisis in 70 years, still that this change is very heterogeneous when one considers each manufactures cement. The ecological analysis is done through comparison between ecological efficiency, pollution indicator and values for CO2 equivalent from cement industry rate, before and after adoption of waste reuse.