Development of continuous steelmaking slag solidification process suitable for sensible heat recovery

Abstract

The COURSE50 project aims at developing technologies to reduce CO 2 emissions from steel works by approximately 30% in Japan. In order to supply the energy required to separate CO 2, a technology for recovering sensible heat from steelmaking slag is being developed as one theme of COURSE50. A twin roll type continuous slag solidification process to obtain a shape suitable for sensible heat recovery was investigated. Sheet-like slag was shaped to a thickness of about 7 mm in a twin roll pilot-scale experiment. The slag thickness depended on the adhesion of the molten slag rather than the thickness of the solidified slag on the roll. The slag condition suitable for the twin roll method was identified as a liquid phase ratio of 60% or more. Based on a laboratory-scale experiment and heat transfer calculations, a combination process using the twin roll method and a countercurrent flow packed bed is expected to achieve a heat recovery ratio of 30% or more from sheet-like slag.