A Study on the Sintering Mechanism of High-Strength Light Bricks Manufactured from Coal Gasification Slag

Abstract

In this article, we report a way to produce sintered bricks from industrial coal gasification slag. Subsequently, we studied the impact of the addition of coal gasification slag and heat treatment on the density and compression strength of sintered materials with controlled variables. In addition, we implemented thermogravimetric analysis-differential scanning calorimetry (TG-DSC), an X-ray powder diffractometer (XRD), and a scanning electron microscope (SEM), as well as optical and thermal measurement devices, to analyze the microscopic structures of sintered materials; this revealed the action mechanism of coal gasification slag on the microscopic morphology and performance of sintered bricks. The volumetric density and compression strength of the sintered bricks were found to be negatively correlated with the amount of coal gasification slag introduced, but positively correlated with the sintering temperature. When the firing temperature was 1150 °C and the addition amount of coal gasification slag was 45%, the sintered brick products, with a predominant crystalline phase of anorthites, could achieve a density of 1.5 g/cm3 and a compression strength of 30 MPa; this met the requirements of the China National Standard GB/T 5101-2017 for MU30 bricks. This report may help with the implementation of coal gasification slag.