Purifying marine clay for the preparation of LC³

Recent studies suggest that marine clay has the potential to substitute cement after calcination, although its reactivity is limited. This paper evaluates the purification of Singapore marine clay, which mainly consists of low kaolinite and high quartz, for use as a cement substitute. The study explores wet sedimentation and surfactant-assisted sedimentation to enhance reactivity in a typical limestone calcined clay cement (LC³) recipe by reducing quartz content. The findings indicate that while wet sedimentation effectively removes quartz, it is less effective for silt due to its smaller size. Surfactant-assisted sedimentation further purifies the clay, with material strength depending on both composition and particle size. Specifically, clay filtered through a 22 µm sieve exhibited improved strength. The study recommends the 22-WS-CC method for its cost-efficiency and feasibility in large-scale implementation without chemical reagents. Overall, this research contributes to the sustainable development of the construction industry by providing insights into the effective utilization of low-grade, impure clays in cement production.