Reduction of natural resource consumption in cement production in Japan by waste utilization

According to Japanese government policy, the input of natural resources should be minimized and input resources should be utilized to the greatest extent possible so that, eventually, minimum waste is generated. The cement industry of Japan has worked hard to maximize waste utilization. Focusing on the cumulative amounts of the elements needed for clinker and gross calorific values, this study estimated the extent to which waste utilization has directly or indirectly reduced natural resource consumption and greenhouse gas emissions associated with cement production at 32 factories in Japan and clarified the effect of waste utilization in the cement industry on the resource productivity of Japan based on information for fiscal year 2008. Had no wastes been utilized, the cement industry consumption of limestone would have been 18% higher; of clay, 2,899% higher; and of energy, 22% higher. The utilization of wastes in the mixing and burning process of cement production directly reduced greenhouse gas emissions (12% emitted gas reduction) by a larger amount than the indirect reduction achieved by their utilization during the admixing process (10% reduction). Waste utilization for cement production contributed to an increase in resource productivity of about 8,000 Japanese Yen/ton.