BASIC ASPECTS OF NICKEL EXTRACTION FROM CHROMITIFEROUS OVERBURDEN

Nickel oxide in an Indian chromitiferous overburden was reduced with a CO-CO2-N-2 gas mixture and the effects of various operating parameter s, such as roasting temperature, time and P-CO, Were studied. An extra ction of more than 90% nickel was achieved by ammoniacal leaching of o re that had been reduced for Ih at 760 degrees C under a gas mixture w ith a volumetric CO/(CO + CO2) ratio of 0.57. The kinetic data were fo und to conform to the Ginstling-Brounstein equation. The applicability of this model was confirmed by evaluating the apparent activation ene rgy with the use of independently constructed differential and integra l plots.