Advancements in eco-friendly metal recovery: Chemical separation and fluidized bed reactor technology

Metals discharged from industrial plants have become a significant contributor to water pollution, particularly in regions undergoing rapid globalization and industrialization. While magnesium is considered a relatively benign metal pollutant, its presence can still lead to environmental concerns due to elevated total hardness levels in industrial wastewater. Moreover, the extraction of magnesium from wastewater presents an opportunity to recover a critical raw material that is in high demand across various industries. Chemical-based methods have traditionally been pivotal in the extraction and removal of impurities such as heavy metals from wastewater. This review aims to explore the conventional chemical-based separation processes and their evolution with the introduction of the relatively novel fluidized bed reactor (FBR) technology for treating various metals, specifically focusing on magnesium. A comprehensive compilation of literature on conventional treatment methods, including chemical precipitation, coagulation-flocculation, and flotation processes, was conducted. Additionally, advancements in heterogeneous and homogeneous fluidized bed granulation for FBR treatment processes were examined. The review sheds light on the advantages and limitations of these processes, identifying key insights and literature gaps. Furthermore, the review outlines potential applications and benefits associated with various extracted magnesium salt or crystal compounds. By synthesizing existing research, this review contributes to a deeper understanding of chemical separation and fluidized bed reactor technology in the context of magnesium recovery and environmental remediation.