Evaluation of the Effect of Reuse of Wastes for Cement Production

Abstract

Cement industry accepts many kinds of wastes from other industries, and contributes to prolong the garbage dump life. It is one of the important roles of cement and concrete industry. From the aspect of circulation, however, it is questionable, because we postpone the problem of wastes. For finding a solution for this problem, it is essential to evaluate the environmental impacts of cement production. The aim of this study is to evaluate the effect of use of wastes and by-products to cement production. In this study, we used three methods for the evaluation: LCA (Life Cycle Assessment), exergy analysis, and TMR (Total Materials Requirement). Ecocement production is evaluated as an example in this study. Besides, a presumed cement production process, in which the wastes used in cement industry are accepted in average, is evaluated. The treatment of disposal was insufficient in conventional LCA. It considered only the environmental load accompanied by energy consumption when the used products are transferred and wasted. In contrast, "zero emission" type system boundary is used in our LCA, in which disposal of materials is assumed to be in completely harmless substances. Moreover, the environmental impacts are evaluated by exergy analysis, in which a measure of the exergy of wasted materials is calculated as potential impact, and by TMR, in which the amounts of direct and indirect materials engaged by mining and discarding of the products are estimated.