An Electrochemical Method for the Formation of Magnetite Particles*

ABSTRACT Magnetite has been widely used in numerous industrial processes and environmental applications. The conventional method for the production of magnetite particles, based on the mixing of ferrous and ferric ions at a 1 : 2 molar ratio, produces high-pH secondary wastewater that requires further treatment. This study investigates an alternative approach based on electrochemical reactions for the production of magnetite particles, a process in which ions of iron are produced by carbon steel electrodes and pure magnetite particles are formed through electrochemical reactions under favorable conditions. To better understand the mechanisms involved, experiments were conducted to examine the effects of various electrolytes—such as those of NaCl, CaCl2, MgCl2, and CuCl2 —and various operating conditions—including temperature and applied voltage—on the formation of magnetite particles. It was observed that magnetite could form in NaCl solutions in the presence or absence of Mg2+ and Ca2+ ions, while only insignificant quantities of magnetite particles were observed in tap water and CuCl2 solutions. A mechanistic study of magnetite formation based on the E-pH diagram is presented, and the reactions involved are identified.