Kinetics of thermal decomposition and hydrogen reduction of Cobalt compounds: A review

• Thermal decomposition and H 2 reduction kinetics of Co compounds has been reviewed. • Reduction with hydrogen of presented Co compounds occur via intermediate steps. • Variety of kinetic models is used to model Co compounds decomposition and reduction. • H 2 reduction kinetics depend on precursor characteristics and process parameters. • H 2 reduction of CoCO 3 and Co(OH) 2 requires more intensive research in the future. Cobalt is an important transition metal that plays a critical role in the growing battery industry, and in hard metal applications and super alloys. Cobalt powder can be produced via solid-state hydrogen reduction of different cobalt compounds from which cobalt oxides have been widely studied since 1960s. Hydrogen is an efficient and environmentally friendly reductant and its utilization in metal refining is being increasingly studied. This paper presents an overview of important findings regarding hydrogen reduction kinetics of cobalt oxides alongside thermal decomposition kinetics of cobalt carbonates and hydroxides. This will assist researchers in the future to choose and modify hydrogen reduction parameters by identifying the factors affecting the overall reduction reaction of different cobalt compounds and characteristics of derived cobalt products.