Formation of uniform particles of cobalt compounds and cobalt

Abstract

Depending on experimental conditions, precipitation from cobalt (II) sulfate solutions in the presence of urea yields finely dispersed cobalt compounds of different chemical compositions and morphologies. The needle-type particles, generated in closed systems, were identified as cobalt (II) basic carbonate. In systems open to air, spherical particles of cobalt (II) basic cyanato carbonate are formed. The latter transform to spherical Co₃O₄ particles on calcining at 300°C, and then can be reduced to metallic cobalt powder by reacting with hydrogen at 300°C. In the presence of sodium dodecylsulfate, unique cone-type particles containing dodecylsulfate ions are produced.