Preparation conditions for the synthesis of alkali-activated binders using tungsten mining waste

Abstract

This study evaluated the results of preparation conditions for the production of an alkali-activated binder (AAB) based on a binary mixture of tailings from tungsten mine waste (TMW), and waste glass (WG) activated with a mixture of sodium silicate (SS) and sodium hydroxide (SH). A 40% by weight WG increased the amorphous nature of the binary blend by 21% without initiating the alkali-silica reaction. The SS-SH activator solution was subjected to a variation of mixing times, and its sensitivity was measured using temperature monitoring and Fourier transform infrared spectroscopy (FTIR). After 20 min of mixing, the SS-SH activator solution showed a 3.13°C reduction in temperature and a 21.4% increase in unbound water content, and as a result imparted a 26% drop in the mechanical strength of TMW-WG AAB at 28 days. The TMW-WG AAB was also determined to develop the highest compressive strength when cured at 80°C for 24 h in sealed conditions. The following conditions, supported by X-ray diffraction (XRD) and FTIR, are responsible for the most significant dissolution of the aluminosilicate oxides.