A new green synthesis method of magnesium ferrite from ferrous sulfate waste

Resource utilization of ferrous sulfate waste has become a bottleneck restricting the sustainable development of the titanium dioxide industry in China. This paper proposes a new solution that utilizing ferrous sulfate waste to prepare spinel-structured magnesium ferrite (MF) particles in micrometer size, through the solid-phase reaction between ferrous sulfate, magnesium sulfate and pyrite under nitrogen protection. Thermodynamics analysis and tubular reactor experiments were performed to analyze the synthetic process. The thermodynamic simulation results showed that the proposed method for synthesizing MF is feasible by controlling the proper molar ratios of raw materials and calcination temperature. Based on this, the reaction mechanism for MF generation via this route was deduced, and the effect of three key parameters including molar ratios of raw materials, calcination temperature and calcination time on the products were investigated. The properties of synthesized MF were characterized via X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), Raman spectroscopy (RS), scanning electron microscope (SEM), and Brunauer-Emmett-Teller (BET) method. Results demonstrated that the as-synthesized MF has a spinel structure and exhibits a micrometre-scale architecture composed of particles with size of 100-300 nm. This green synthetic method of MF provides a promising way to utilize ferrous sulfate waste, because it is in accordance with the concept of recycle economics and worthy of commercialization. (C) 2018 Elsevier B.V. All rights reserved.