This study was investigated to fabricate nanosized cobalt (Co) powder from cobalt hydroxide Co(OH)(2) recovered from spent lithium ion battery. Direct process newly proposed was attempted to transform phases as follow: Co(OH)(2) -> Co3O4 -> Co. The variation of weight with time of the sample was measured using thermogravimetric analysis (TGA) and it was found that weight loss was observed over 500 degrees C. Thermal treatment was conducted to determine proper operating time for phase transformation of Co3O4 at 500 degrees C. Subsequently, hydrogen reduction was carried out on the effect of temperature, reaction time and flowrate. In the long run, nanosized cobalt powder was successfully fabricated with a mean particle size of 100-500 nm as well as purity of 99.21 wt.%. (C) 2016 Elsevier B.V. All rights reserved.