Preparation of alkali-activated grouts as an innovative method for utilisation of gold ore tailings

Abstract

This study reports the use of gold ore tailings (GOTs) in alkali-activated grouts. A series of tests were performed to investigate the engineering properties of the alkali-activated grout pastes with different mix proportions. The ranges of water-to-solid ratios and the mechanically ground GOTs contents were 0.6–1.5 and 0–50%, respectively. It was found that the bleed capacity, mini-slump diameter and compressive strength decreased with the increase in mechanically ground GOTs content, while the apparent viscosity and setting time were increased. To ensure sufficient flowability, reduced bleeding, a reasonable setting time, and adequate strength, the water-to-solid ratio and the mechanically ground GOTs contents were recommended as 1.0 and 30 wt.%, respectively. At the same time, the hydration properties of the alkali-activated grouts were investigated. It was found that mechanically ground GOTs exhibit pozzolanic activity and possess similar hydration properties to ground granulated blast-furnace slag (GGBFS), although its pozzolanic activity is lower than GGBFS. Mechanically activated GOTs can react with calcium hydroxide to form C–S–H gel and ettringite crystals in the presence of anhydrous gypsum. This innovative method provides reliable technical indexes and scientific basis for utilisation of GOTs.

Keywords:

• Gold ore tailings
• mechanical grinding
• alkali-activated grouting material
• pozzolanic reaction activity
• hydration properties

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Natural Science Foundation of China (No. 51674161), Key Laboratory of Gold Mineralization Processes and Resource Utilization Subordinated to the Ministry of Land and Resources (No. KFKT202110), and Key Laboratory of Metallogenic Geological Process and Resources Utilization in Shandong Province (No. KFKT202110).