An assessment of the carbothermic reduction of ilmenite ore by statistical design

The demand for titanium ores and concentrates is largely driven by the demand for titanium pigments and titanium metal products, which in turn follows the growth of the global economy. The carbothermic reduction of ilmenite up to 1200 °C was found to proceed through the formation of a series of oxides (TinO2n−1) and iron metal. Statistical analysis provides a method to analyze and to model as well as to optimize the reduction process of ilmenite ore. Factorial design was used to determine the significance and the interaction between the studied factors. The effect of operating parameters on the reduction process of ilmenite ore was followed by iron metallization and extent of reduction. The main parameters investigated were time, temperature, and particle size. The results of the design showed that the metallization percentage reached up to 99% for a period of 6 h at 1200 °C using particle size a 200 mesh (−74 μm). The most interesting finding is that the statistical design has the limitation in predicting the reaction behavior especially when the reaction is controlled with more than one mechanism. To get the most benefits from the statistical design at these complex situations, either the design should be divided into certain number of designs according to the controlling mechanism or the transition region between two mechanisms should be identified which needs a good understanding of the studied process. In this paper the two routes were tested to confirm this finding.