Recovery of Magnesium from Industrial Effluent and Its Implication on Carbon Capture and Storage

Municipal and industrial wastewater can be a potential source of magnesium. Therefore, the development of magnesium recovery technology can both release the burden of wastewater treatment and help recycle the metal, which is in high-market demand. Also, the recovery of magnesium in the form of magnesium carbonate has an implication on carbon capture and storage (CCS). In this study, fluidized bed homogeneous crystallization (FBHC) was employed for the recovery of magnesium from actual industrial effluent. The optimal conditions for the operation of FBHC were pH, 11.3; [Mg2+]/[CO32-], 1.2; surface loading rate, 1.8 kg/m2 h; and upflow velocity, 15.5 m/h, where the total recovery (TR) and crystallization (CR) efficiencies reached 88.5 and 85.4%, respectively. The recovered products were of high purity (93.5%) and in the form of nesquehonite (MgCO3·3H2O) pellets (size 1.2 mm), which could be further reused easily. From the scanning electron microscopy analysis, it was observed that they possessed a round shape and a smooth surface. In summary, FBHC is a promising recovery technology for magnesium-rich wastewater, where carbon capture and storage can be simultaneously integrated