Authors: M.Y. Solar, I. Candy and B. Wasmund
CIM Magazine, vol. 3, no. 2, 2008
Abstract
The nickel laterite industry is divided into two camps when it comes to the grade of the ferronickels produced. One group, led by Falcondo and Cerro Matoso, markets high grade ferronickels in the range of 35-40% Ni while another, led by SLN and the Japanese smelters, favour lower grades in the range of 20-25%. However, since the ores processed by these smelters vary widely in terms of nickel content and iron to nickel ratios, it is probably more accurate to classify these smelters in terms of their iron recovery: Falcondo and Cerro Matoso smelt at lower reduction potentials and thus recover only 15-30% of the iron in their ores, while SLN and the Japanese smelters are very reducing and recover 45-65% of their iron. Low reductions imply higher slag losses and lower nickel recoveries but also lower power and reductant requirements, higher reductions the reverse. The question is therefore whether an economically optimum ferronickel grade exists for processing any given ore. The present paper proposes a methodology for determining this optimum and concludes that nickel laterite smelters should favour low reductions and production of high grade ferronickels.
