Potentiality of coal mining waste to obtain geopolymers

Abstract

Geopolymers are chemically bonded ceramics formed at room temperature and obtained using aluminosilicates and alkali activators. Geopolymers have found applications beyond construction, such as in wastewater treatment and ceramics. This research aims to develop geopolymers using coal mining waste (CMW) for various purposes. The waste used in this study was obtained from the Barro Branco layer in companies located in southern Santa Catarina/Brazil. The waste was thermally treated at 900 °C for 160 min, followed by grinding and characterization using X-ray fluorescence spectroscopy, X-ray diffraction, and particle size analysis. Geopolymeric samples were produced using 60 wt% waste, 25 wt% sodium silicate, and 15 wt% 10 M NaOH. The specimens were divided into three groups and cured using different methods. The results showed that thermal curing enhanced waste reactivity, reduced curing time, and improved compressive strength. However, long-term submersion curing decreased compressive strength due to sodium leaching, reducing reactivity.

Keywords:
coal; tailings; mining; sustainability