Utilization of aluminum sludge (AS) to enhance mine tailings-based geopolymer

Abstract

This paper investigates the feasibility of using aluminum sludge (AS) to enhance copper mine tailings (MT)-based geopolymer. The Si/Al and Na/Al molar ratios were adjusted by adding AS into the high silica content MT and using different amounts of NaOH. Unconfined compression tests and SEM, XRD, and FTIR studies were conducted on geopolymer specimens prepared at different Si/Al and Na/Al ratios and after 7-day curing. The results indicate that by adding AS and utilizing appropriate amount of NaOH, the unconfined compressive strength increases significantly. The main reason is because the addition of AS along with utilization of appropriate amount of NaOH makes both the Si/Al and Na/Al ratios reach the optimum values for geopolymerization, leading to higher degree of geopolymerization and more compact geopolymer microstructure. Based on this study, it can be concluded that AS can be used to effectively enhance the MTbased geopolymer.

Experimental study of geopolymer mortar with incorporated PCM

“…For all specimens, the average 14 day UCS and 28 day UCS are only 8.8% and 14% higher than the average 7 day UCS, respectively. This means a major portion of the ultimate strength of geopolymer mortar is gained within the first 7 days, which confirms the findings from [27,[32][33][34][35][36]. Fig.…”

Sustainable solidification of ferrochrome slag through geopolymerisation: a look at the effect of curing time, type of activator and liquid solid ratio

“…The reduction in the intensity of the quartz peak was also evidence of the participation of quartz in the dissolution reactions. This phenomenon of the dissolution of crystalline species has also been reported in literature [24]. GP0 and GPS1 showed the formation Calcium Silicate Hydrate (CSH) around 20°and 78° [28,29].…”

“…This was due to that the aluminate activation resulted in the formation of calcium silicate hydrate and calcium aluminate silicate hydrate in the geopolymers whereas silicate activation resulted in the formation of calcium silicate hydrate only. It has been shown that the right balance between Si and Al in the precursors or activating materials is important to get a high UCS [24]. This is because the two have to dissolve and then rearrange into a three dimensional structure.…”

Management and valorisation of wastes through use in producing alkali‐activated cement materials

“…However, elevated temperature curing was required to accelerate the hardening of the specimens. Ren et al also showed that aluminium sludge could be effective as a secondary source of Al 2 O 3 in an alkali‐activated blend with copper mine tailings, to decrease the overall Si/Al molar ratio and improve the performance of the resulting binders.…”