Effect of mechanical grinding on pozzolanic activity and hydration properties of siliceous gold ore tailings

By G. Yao, Qing Liu, Junxiang Wang, Peng Wu, X. Lyu. Journal of Cleaner Production, 2019

163 citations recorded by the source corpus.

Abstract The conversion of gold ore tailings into value-added products is an urgent problem that requires a solution. In this study, two different type of mixtures (with minor addition of activator to excite the activity of mechanically activated tailings, and a mixture of cement and tailings to determine activity index of tailings) were prepared to investigated the effect of mechanical grinding on pozzolanic activity and hydration properties of gold ore tailings. The results demonstrate that the relative crystallinity of main mineral phases in tailings is decreased by mechanical grinding. In particular, the relative crystallinity of mineral phases of muscovite is decreased to 37% after an 80-min grinding. Ground tailings possess higher pozzolanic activity compared with that of raw tailings in an alkaline environment, and the activity of mechanically activated tailings is gradually increased with grinding time. The activity index (28 d) of cement–ground tailing mortar reaches as high as 78.99% and satisfies the Chinese National Standard GB/T 2847-2005. This indicates that mechanically activated tailings are suitable as Portland cement additive. Its hydration products are amorphous C–S–H gel in CaO-activated ground tailings system, as well as ettringite crystal in the presence of anhydrite. Based on the energy dispersive spectroscopy analysis, amorphous C–S–H gel solidifies Al3+, K+, and Na+ during the hydration process. The present experimental research provides a theoretical basis for utilizing gold ore tailings in cement as additives, which would be environmentally friendly and cost-effective.

Subfields: Biomedical Engineering, Building and Construction, Civil and Structural Engineering

View Paper: https://www.semanticscholar.org/paper/45b2bbaa569dcc71bafb0c10c890708b2c156cb9