Fuel oil reduction of polymetallic manganese sea nodules of Indian Ocean for extraction of nickel, copper and cobalt

Sea nodules from the National Institute of Oceanography, Goa were subjected to a reduction roast with fuel oil along with sodium chloride and were leached with an ammonia and ammonium carbonate solution. The process parameters studied were effects of temperature, amount of fuel oil and quantity of additive. The kinetics of leaching and the effect of concentration of leachant were studied. The recoveries of nickel, copper and cobalt were 93.0%, 99.0% and 78.0%, respectively on reduction at 750°C for 1 hour and subsequent ammonia leaching of the calcine for 4 hours.