Synthesis of sodium iron oxide from sodium carbonate and ilmenite-based iron hydroxide via a wet milling method

In this preliminary study, we investigated the effect of calcination temperatures on the mineral phases and the microstructures of sodium iron oxide. The experiment was conducted by mixing sodium carbonate as the Na precursor and iron hydroxide extracted from ilmenite sand as the Fe precursor through a wet-milling method in ethylene glycol. Then, the mixture was calcined at 600 and 800 °C in air atmosphere conditions. The mineral phases and the morphology of the final products were then analyzed by XRD and SEM methods. The XRD results show that the calcined materials at those temperatures comprise of five different mineral phases such as NaFeTiO4, α-NaFeO2, Na0.75Fe0.75Ti0.25O2, Na0.75Fe0.75Ti1.25O2, and Fe1.35Ti0.65O3. As the calcination temperature increases, the alpha NaFeO2 and NaFeTiO4, phases grow into more dominant, but others phase decreases. At 600 °C, the calcined product consists of rod-like particles and growing fine particles. Meanwhile, the calcined product at 800 °C exhibits unique microstructures, showing larger rod-like and two-dimensional particles.