Characterization of Slag Reprocessing Tailings-Based Geopolymers in Marine Environment

Abstract

In this study, copper slag reprocessing tailings (CSRT) were synthesized into geopolymers with 40%, 50% and 60% metakaolin. The evolution of compressive strength and microstructures of CSRT-based geopolymers in a marine environment was investigated. Except for compressive strength measurement, the characterizations of X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM) were included. It was found that marine conditions changed the Si/Al ratio in the sodium-aluminosilicate-hydrate (N-A-S-H) gel backbone, promoted the geopolymerization process, led to more Q4(3Al), Q4(2Al) and Q4(1Al) gel formation and a higher compressive strength of the geopolymers. This provided a basis for the preparation of CSRT-based geopolymers into marine concrete.

The Effect of Chromium on the Chemical and Physical Properties of Industrial Sludge Based Geopolymer

“…EDS analysis of the reference sample indicates that the main elemental composition of the geopolymer is O, Si, Al, Na, which revealed the formation of sodium based aluminosilicate gel (N-A-S-H gel) as amorphous product [32][33][34]. Consequently, these results were consistent with the compressive strength result.…”

Gel Evolution of Copper Tailing-Based Green Geopolymers in Marine Related Environments

“…Although Davidovits defended that geopolymers differ from alkali-activated materials (AAMs) in chemistry, molecular structure, long-term durability, etc., plenty of works use the term geopolymer when dealing with AAMs, even in high-calcium alkali-activated systems [2,3]. Geopolymers are mainly studied in the application of green concrete materials for the replacement of ordinary Portland cement (OPC) material [4][5][6], although there are other particular applications of geopolymers that are also interesting, for example, the synthesis of waste-based materials into marine concrete geopolymers [7][8][9].…”

“…The 3D microstructure and compacted tetrahedral-silica and aluminum-structure inner geopolymers enables them to resist exotic physical force and chemical corrosion. Wu et al [9] successfully synthesized geopolymers under the marine environment with metakaolin and copper slag reprocessing tailings; meanwhile, they found the chemical characteristics of geopolymers were much improved due to the changing Si/Al ratio in the micro-structure, promoting the geopolymerization process. Besides, Tennakoon et al [11] pointed out that the Cl − diffusion coefficient in geopolymers was much lower than in OPC concrete even under an extended test period.…”