Preparation of Refractory Materials from Ferronickel Slag

The amount of slag produced from a typical ferronickel smelting process is 4 to 6 times that of the metal product, and handling this slag is a huge challenge to the ferronickel industry. The feasibility of a technological route for preparing refractory materials from a ferronickel slag was verified in this study. Based on the thermodynamics analysis, the effect of the sintering temperature on the properties of refractory material from the slag was studied in the presence of magnesia. The results of thermodynamics calculation showed that the reaction of MgO with SiO2 generated forsterite and enstatite, whereas the reaction between MgO and Fe2O3/Al2O3 produced corresponding magnesia spinels. The experimental results showed that a refractory material with refractoriness of 1580 degrees C, bulk density of 2.88 g/cm(3), compressive strength of 106.9 MPa, and apparent porosity of 5.8% was obtained under the conditions of magnesia addition of 15 wt %, sintering temperature of 1350 degrees C and sintering time of 3 h. With increasing sintering temperature, the bulk density and the compressive strength of refractory material increased but the apparent porosity decreased, mainly attributed to the formation of the liquid phase which promoted the densification of the refractory material.