A Material Flow Analysis of Phosphorus in Japan The Iron and Steel Industry as a Major Phosphorus Source

Summary The demand for biofuels has recently increased because of ris-ing prices of fossil fuels and diversification of energy resources.As a result, the demand for sugarcane and corn has been in-creasing, not only for food production, but also as sourcesof energy. In this context, securing supplies of phosphorus,required as an essential nutrient in agricultural production,has considerable implications that extend beyond food andagricultural policy. It is therefore important to consider thequantity and availability of phosphorus resources that remainuntapped, because the demand and supply of phosphate oreis currently becoming very tight, and Japan has no domesticphosphorus resources.To identify potential phosphorus resources, we have inves-tigated the material flow of phosphorus within Japan, includingthat in the iron and steel industry, on the basis of statisticaldata for 2002. Our major finding is that the quantity of phos-phorus in iron and steelmaking slag is almost equivalent to thatin imported phosphate ore in terms of both the amount andconcentration. We also found, by means of a waste input–output analysis and a total materials requirement study, thatthe phosphorus potentially recoverable from steelmaking slagby a new process that we have proposed has considerable en-vironmental and economic benefits. Concerning the restrictedsupplies of phosphorus resource, it is important to considerthe quantity and availability of phosphorus resources thatcurrently remain untapped. From that viewpoint, steelmakingslag would be expected to be a great potential resource forphosphorus.www.blackwellpublishing.com/jie