Recovery of Iron-Based Coagulant from Waste Laterite Ore through Chemical Leaching for Efficient Water Treatment

Open dumping and disposal of waste iron ore in freshwater and landfills are increasing environmental concerns. Therefore, following the environmental sustainability and circular economy approach, this study recovered iron-based coagulants from waste laterite ore (WLO) and assessed their performance in water treatment. Chemical leaching of WLO was performed using HCl with varying acid concentrations, temperatures, and treatment times. The optimum iron solubilization efficiency of 86% was achieved at an optimized HCl concentration of 13 mol/L, a reaction temperature of 90 °C, a mixing speed of 500 rpm, and a treatment time of 240 min. The recovered WLO-based iron coagulant exhibited a greenish color and showed promising performance in treating water from the River Indus Canal, particularly in removing turbidity and heavy metals. This performance of the WLO-based iron coagulant was nearly identical to that of conventional ferric chloride. Overall, recovering iron-based coagulants from WLO may reduce the cost of coagulating drinking water or wastewater. Furthermore, the present study's findings will be useful in protecting the environment by either not discharging the WLO into freshwater bodies or by dry stacking.