Research on mineral characteristics of converter steel slag and its comprehensive utilization of internal and external recycle

Converter steel slag is a vast amount of solid waste generated in the steelmaking process that has very low utilization rate in China and is usually deposited as waste. This paper investigates the physical and chemical characteristics of converter steel slag, as well as its comprehensive utilization of internal and external recycle. The results show that the mineral phases of converter steel slag mainly include dicalcium silicate (C2S), tricalcium silicate (C3S), RO phase and calcium ferrite (2CaO·Fe2O3) and so on, where the proportion of silicate phase is about 50%. Various mineral phases of converter steel slag show different morphologies in grey levels and shapes, and have great differences in Vickers hardness. The resource utilization of steel slag should follow the principle of internal and external recycle, which involves several technologies on recycle, separation and preparation of useful materials such as scrap steel, iron concentrate and steel slag powder. Five technologies, which include the volume stability technology, separation and recycling technology of iron and slag, efficient preparation technology of powder, the activation technology and application technology of steel slag powder in cement and concrete, are keys to achieve the efficient and bulk utilization of steel slag and their actions were presented by the relevant experimental researches as well.