Preparation and properties of microcrystalline foam ceramics from silicon manganese smelting slag

Abstract

In order to solve the problem of high accumulation of silicon-manganese slag, this paper proposes a method to prepare foam ceramics with high porosity using silicon-manganese slag as raw material. Two types of silicon-manganese slag were obtained from different regions of Ningxia, China, and used to prepare foam ceramics. This was done with the help of one-step sintering method by adding SiC as a foaming agent and borax as a flux. The effects of chemical composition and crystal phase difference of silicomanganese slag on the physical properties, phase and micromorphology of foam ceramics were investigated. By adjusting the firing temperature and foaming agent content, the optimal process for the preparation of foam ceramics by two kinds of silicomanganese slag was determined. The phase and microstructure of the samples were characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM), and physical analysis was carried out. The results show that when the sintering temperature of the Huiyi silica manganese slag (HYSM) sample is 1100 °C, the bulk density reaches the minimum value of 0.41 g/cm3, while the porosity and compressive strength are 86.26 % and 0.95 MPa, respectively. On the other hand, when the sintering temperature of the Tianyuan silica manganese slag (TYSM) sample is 1110 °C, the packing density reaches a value of at least 0.51 g/cm3, while the porosity and compressive strength are 80.07 % and 2.09 MPa, respectively. The XRD and SEM results show that the crystalline phase of the HYSM sample is mainly magnesium feldspar, while that of the TYSM sample is mainly diopside. In this study, two kinds of silicon manganese slag with different physical and chemical properties were used to prepare foam ceramics with high porosity, and a theoretical basis for the large-scale use of silicon manganese slag in foam ceramics was presented.