Because of the comparatively large deposits, the nickel laterites of Sukinda, Orissa, India, have been investigated by many workers with the aim of developing suitable extraction techniques. Chander and Sharma (1981) studied the extractability of Ni from lateritic nickel ore by reduction roasting with H sub 2 --H sub 2 O mixtures and ammonia leaching. Panda et al. (Trans. Indian Inst. Metals , 26, (6), 483) also reported the results of reduction roasting at high temeperature, followed by ammonia leaching and of sulphuric acid leaching of lateritic nickel ore at elevated temperature and pressure to extract most of the nickel and cobalt £¦#118alues. The effect of CO sub 2 --CO and H sub 2 O--H sub 2 couples were both separately studied and in combination on the extraction of nickel from both serpentinic and limonitic ores. The kinetics of sulphuric acid leaching of reduced laterites have been reported previously. The main objective for adopting such drastic reaction conditions is to avoid the large-scale contamination of the leach liquor by Fe. 8 ref.