Structure and properties of secondary cobalt powder

Abstract Cobalt is widely used in batteries, carbide, and many other industries due to its good performance. Secondary cobalt powder is an important source of cobalt. The performance of secondary cobalt and ore cobalt are studied in this paper. Secondary cobalt carbonate and ore cobalt carbonate possess monoclinic structures, but the secondary cobalt carbonate XRD diffraction peak half-width is more than twice the ore cobalt carbonate. In addition, the continuity of lattice fringes of secondary cobalt carbonate is poorer than the ore cobalt carbonate, so the crystallization of secondary cobalt carbonate is not as good as the ore. One-step production of the metal produces cobalt with a face-centered cubic structure. However, even though the structure performance of the secondary cobalt has greatly improved, the crystallization of ore cobalt remains better than that of secondary cobalt. The two-step product is close-packed hexagonal metal cobalt, and the ore cobalt product prepared using a two-step (air + H 2 ) method is better than that from secondary cobalt. The structure and properties of secondary cobalt product prepared using a two-step (N 2 + H 2 ) method can achieve structural performance equal to that of the ore. The optimum sintering temperature for Co powders is 825–850 °C, and the relative density can be greater than 97%. The hardness of secondary cobalt is higher than that of ore cobalt.