Optimizing and characterization of titanium dioxide extracted from black sand using response surface methodology...

Titanium dioxide is used in different applications such as paints, plastics, paper, and water treatment. Various routes are applied for the recovery of TiO₂ according to the available raw material. The aim of this work is the application of response surface methodology for optimizing the recovery of TiO₂ from illeminite beach sand deposits (black sand, Kafr-El-Sheikh, Egypt) with high purity using sulfuric acid. Utilizing local raw material to obtain titanium dioxide with high purity for applications in paints and energy applications. Applying a simple method for separating iron, which is present in high weight% (49%). Application of the RSM approach in the extraction of titanium dioxide to determine the interaction of the studied parameters and determine the model relating them to the yield of titanium dioxide. characterizations of raw material are applied; X-ray fluorescence (XRF) indicates the chemical composition, and the weight% of titanium dioxide is 43%. The illeminite phase is confirmed by X-ray diffraction (XRD) of the raw material sample. The average particle size of illeminite powder is measured using screen analysis, and it is around 118 micrometers. Three selected parameters affecting the leaching of illeminite are studied using the Response Surface Methodology (RSM) technique: temperature (60-120℃), sulphuric acid concentration (4-12 M), and time (1-5 h). Maximum conversion (84%) is obtained at the optimum conditions predicted by the RSM model at Temperature (120 ℃), time 4.2 h, Concentration (12 M). The relation between the studied parameters and conversion is represented by a reduced cubic model with R² = 0.973 and p-value = 0.0001, which confirms the accuracy of the model. The prepared titanium dioxide is separated from the filtrate solution by hydrolysis at 109 °C for 3 h, using EDTA as a complexation agent to capture the solvated iron. The hydrated titanium dioxide powder is dried, then calcinated at 500 °C for 3 h to produce titanium dioxide in an anatase phase. The prepared sample is examined using XRF, XRD, and SEM-EDX. 96.4% purity of titanium dioxide is formed; the XRD pattern of the examined sample confirmed the formation of the anatase phase. SEM images display that TiO₂ has a uniform spherical morphology. The EDX spectrum shows that most of the sample is TiO₂. The average particle size of the prepared titanium dioxide using a particle size analyzer is about 78.82 nm.