The present study deals with the nickel extraction and iron dissolution from nickeliferous laterite by a process of sulfation-roasting-leaching.To optimize the roasting process,response surface methodology(RSM)was utilized which employed two-level and two-factor full factorial central composite design(CCD).The factors of roasting temperature and time were studied. Experiments were carried out for fitting two non-linear regression models of nickel extraction and iron dissolution.Predicted values obtained were close to experimental values,indicating the suitability of the models.Three-dimensional surface plots and contour plot were helpful to predicting the results by performing only limited set of experiments.An area of nickel extraction from 75%to 78% and iron dissolution from 5%to 10%is obtained by an overlaid contour plot.The samples roasted at different temperatures and for different durations were characterized by XRD,which show a good agreement to iron dissolution analysis.
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