Current Development of Slag Valorisation in China

Abstract

Slags are byproducts of the metallurgical industry. It is of importance to recycle materials and recover heat from metallurgical slags to reduce the energy consumption and environmental impact of steel industry. China is the largest iron- and steelmaking slag producer in the world, and intensive efforts have been made during last decades for slag valorisation, including industrial facility development for the slag treatment and applied research on slag engineering. In this paper, the current state of iron- and steelmaking slags valorisation in China is reviewed. The main hot stage slag valorisation processes were introduced to deal with slag granulation, metal recovery, and slag products quality. In addition to the slag granulation process with pollution control and continuously dewatering (INBA™ process), several modified blast furnace (BF) slag granulation methods are currently being applied in China. The dry granulation process flow for BF slag and its pilot scale industrial trials are also described in this paper. Nowadays, around seven industrial BOF slag granulation processes are operating in China with a common goal to stabilise the slag. The hot stage steel slag (BOF) pyrolytic self-slaking process has made progress and are applied in a number of large steel companies in China. The slag valorisation in China improved gradually not only in quantity but also in quality, thereby increasing the economical and environmental benefits. Current researches and new developments are focusing on the dry granulation of molten BF slag with high efficiency of heat recovery.