Heat treatment parameters of preparing glass-ceramic with electrolytic manganese residue and their properties

Abstract

Electrolytic manganese residue (EMR) is a harmful waste that is largely generated during the manufacturing of manganese powder but rarely used. In this work, the preparation of glass-ceramic (GC) was conducted using 100% EMR, and the governing factors, i.e., nucleation temperature and time and crystallization temperature and time of the raw glass powder from the sintering of EMR were determined through differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, with the aid of chemical analysis and the measurement of the density, the porosity, the shrinkage rate and the micro-hardness. Results showed that the nucleation temperature and time are two important parameters governing the crystal type and crystallization degree of the GC, and the optimal parameters of the thermal treatment were determined to be 750 °C and 2 h, with the main crystal phase being diopside. Although the crystallization temperature and time have no significant effect on the main crystal phase type, it greatly affects the sintering process of the raw glass powder. At the optimal crystallization temperature of 1080 °C and crystallization time of 1–2 h, a glass-ceramic with porosity of 1%, shrinkage degree of 40% and micro-hardness of 400 MPa can be obtained. Micro-crystals of about 500 nm are found evenly distributed in the base glass. Dissolution results show that the Mn ion of the EMR can be fully stabilized in GC, which shows that the use of GC will be environmentally friendly.