Response Surface Methodology Applied to Optimize the Experimental Conditions for Preparing Synthetic Rutile by Microwave Irradiation

摘要

In this paper, response surface methodology (RSM) was implemented to optimize the experimental conditions for preparing synthetic rutile from high titanium slag by microwave irradiation. The effects of the preparation variables, such as temperature, microwave power, and time, on synthetic rutile content in the product were systematically investigated. The interaction between the dependent and independent variables were carried out in the central composite design (CCD) method, which was part of RSM. The experimental data obtained were fitted with a second-degree polynomial equation using nonlinear regression analysis. According to results from analysis of variance (ANOVA), also part of RSM, R2 value of 0.9691 indicated that predicted values are in good agreement with experimental values. The optimization process is obtained by solving the nonlinear regression equation and analyzing the response surface and contours. The optimum preparation conditions are obtained: synthetic rutile content of 88.61%, temperature of 1209 K, microwave power of 2.5 kW and time of 48 min. The specific polymorphic phase transition and the microstructure of synthetic rutile under the optimum condition are analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively.