Effect of Fineness on Mechanical Properties of Cementitious Material Made from Magnesia Slag

Magnesium slag is a kind of solid waste discharged by magnesium alloy related industries in the process of producing magnesium products or their alloys. Its composition is similar to Portland cement clinker, so it has great potential to be used as a new cementing material. In this paper, magnesium slag cementitious material specimens with different fineness were made by imitating the actual production environment. The flexural strength and compressive strength of specimens with different curing ages were tested, and the influence of fineness on them was analyzed. The results show that the fineness has a significant effect on the mechanical properties of pure magnesium slag cementitious materials. Its effect on the early strength is greater than that on the later strength. But the flexural strength and compressive strength will not always increase with the increase of fineness. There is a reasonable range of fineness.

The effect of sintering temperature on the structure and properties of calcium hexaluminate/anorthite ceramics

The calcium hexaluminate/anorthite composite are prepared by magnesia slag, kaolin and industrial alumina at different sintering temperature. The effect of sintering temperature on the structure and properties are investigated by X-ray powder diffraction and scanning electron microscopy. The results show that the calcium hexaluminate begins to form at 1300?C and continues to form in a large amount between 1400?C and 1500?C, however, there is a phase transitions form gehlenite to anorthite between 1300?C and 1400?C. CA6 grow preferentially along the basal plane direction. When the crystals touch each other, the CA6 crystals turn to grow up along the axial direction. The apparent porosity decreases and bulk density increases and the flexural strength increases with the rising of the sintering temperature.