Preparation of highly active MgO by carbonate hydrogenation and its application in separation of cobalt and nickel

As a significant industrial material, MgO is mainly obtained by the pyrolysis of magnesite (magnesium carbonate) under air conditions, producing large amounts of CO₂ and contributing to global warming. In this work, the MgO was prepared using the hydrogenation reduction method. The reaction conditions led to CO₂ emissions of <1% and an overall temperature decrease of ~80°C. The highly active MgO prepared by hydrogenation reduction led to a precipitation rate of Co and Ni >99% with a short separation time. Electron paramagnetic resonance, CO₂ temperature programmed desorption, and diffuse reflectance infrared spectroscopy analyses showed that the MgO prepared by hydrogenation contained oxygen vacancies, which improved the alkalinity of the MgO and promoted the precipitation of Ni²⁺ and Co²⁺ by adsorption of hydroxyl oxygen to induce water dissociation, thereby enhancing their separation efficiency.