The treatment of desulfurization ash (DA) by high-temperature can solve the increasingly environmental risk caused by the accumulation desulfurization ash on the one hand, and realize the reuse of Ca and S on the other. However, the understanding of the high-temperature reduction decomposition process of desulfurization ash is still vague. In this study, a multivariate and multiphase reaction mathematical model of the complex system of desulfurization ash, carbon, and gas is established by using the principle of minimum free energy. The modeling results show that the reductive decomposition of DA has four stages, and the decomposition products are different in each stage. This result confirms that the optimal thermodynamic conditions to obtain only CaO as a decomposed product are a temperature greater than 1400 K and a C/S molar ratio of 0.5. Further, the processes of CaO and CaS production are parallel competitive reactions, but are regulated by different factors at different stages. A micropositive pressure equilibrium reaction crucible was designed for laboratory DA decomposition experiments. The correctness of the calculation result of the minimum free energy mathematical model is proved by the high temperature reductive decomposition experiment. When the temperature and C/S molar ratio are 1500 K and 0.5, the DA decomposition rate can reach 100%. The main reaction product is spherical CaO, the minimum S content is approximately 1.5%, and the desulfurization rate can reach approximately 70%. The present strategy is highly promising for application in industrial DA recycling processes.

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In order to improve the corrosion resistance of magnesium alloys, ZnO-HA coating was prepared on the surface of magnesium alloys by using ultraviolet (UV) irradiation and hydrothermal method. The effects of ultraviolet irradiation time on the microstructure, the electrochemical properties and corrosion resistance of ZnO-HA coating were studied. The results indicated that the ZnO-HA coating obtained by 24 h of UV irradiation combined hydrothermal method was dense and uniform, without any cracks, and it was mainly composed of nanoparticle-like HA and flake-like ZnO. Electrochemical properties and corrosion resistance of ZnO-HA coated magnesium alloys were studied in simulated body fluid (SBF). Compared with the bare magnesium alloys, the coated magnesium alloys have good corrosion resistance. In vitro immersion experiments, ZnO-HA coating could provide good protection for the magnesium alloys substrate, indicating that ZnO-HA coating prepared by UV irradiation combined hydrothermal method can be used as a potential modified biomaterial for magnesium alloys.