Achieving stable steelmaking basic oxygen furnace slag through treatment by self-disintegration high pressure process

Abstract

The basic oxygen furnace slag generated during steelmaking can be reused as aggregates in civil engineering because of its chemical composition and technological properties. However, the utilization of steel slag in practical applications is quite low due to its low volume stability. In this work, highly stable slag is obtained by the environmental-friendly self-disintegration high pressure (SDHP) process. In this method, the molten slag is initially crushed to form numerous small bulks. Subsequently, the slag bulks are treated by the self-disintegration process at a high pressure to obtain the highly stable steel slag. Thermodynamic evaluation and experimental investigation reveal that high pressure of steam promotes the hydration reaction. At a pressure of 0.2 MPa, the free lime (f-CaO) content and immersion expansion rate of the steel slag treated by this method are reduced to 1.5% and 0.9%, respectively. Both of these values satisfy the requirements specified in the national standards (GB/T 25029-2010 and GB/T 20491-2006). Moreover, the treatment time is reduced to 1.5 h, which is far lower than the treatment times required for traditional methods.