Use of Monosodium Glutamate (MSG) for Green Leaching Process: An Overview

Monosodium glutamate (MSG) is a sodium salt of glutamic acid, a type of amino acid occurred naturally in some type of foods. MSG has the chemical formula of C₅H₈NO₄Na-NH₂, which is used mainly as flavour enhancer. In mineral processing, MSG has been tried as lixiviant in base metals leaching from secondary sources such as Zn and Cu from electric arc furnace dust and Li and Co from spent lithium-ion battery cathode. The efficacy of base metal leaching using glutamate is mainly contributed by the ability of glutamate to form metal complex especially in alkaline leaching conditions. Leaching in alkaline conditions also pose advantage in terms of leaching selectivity. Fouling elements such as Fe, Al, Mg and Ca are selectively enriched in solid residue. However, further research is needed to establish the optimal leaching conditions using MSG as lixiviant. This review paper will discuss the research direction in hydrometallurgical metal extraction using MSG, including possible improvements and disadvantages.