Design of experiments to study the extraction of nickel from lateritic oreby sulphatization using sulphuric acid

Experiments were designed to optimize the sulphatization of a mechanical mi xture of chemically pure nickel and iron oxide and a lateritic ore using su lphuric acid. The significance of various parameters and their selectivity for nickel extraction over iron have been established. The interaction amon g the operating parameters has been studied using statistically designed ex periments and the data, thus obtained for the pure system, was correlated w ith that for the lateritic ore. Regression equations were formulated for bo th systems and the extraction was represented as a Function of response var iables. The accuracy of the equation has been verified by Fisher's adequacy test. It was observed that the coefficient of temperature was the most dom inant, Followed by acid concentration. Interestingly, the time factor induc es a small effect on extraction. The process has been further optimised usi ng the steepest ascent method. (C) 2000 Elsevier Science B,V, All rights re served.