Study on desulfurization performances of magnesium slag with different hydration modification

Modified magnesium slag could be used as a kind of practical desulfurizer. Four modification methods were studied in this paper, which were magnesium slag hydration, magnesium slag/fly ash hydration, magnesium slag quenching hydration and magnesium slag/additives hydration. The desulfurization performance of modified magnesium slag was characterized by its calcium conversion rate. The desulfurization experiments were carried out in Thermal Gravimetric Analyzer. Based on hydration kinetics and fractal theory, the relationship between desulfurization performance and hydration degree or fractal characteristics were, respectively, analyzed. The results showed that the optimal temperature of desulfurization reaction was 920 °C. When the mass ration of fly ash and calcium silicate of magnesium slag (MR) was 20, hydration time (tH) was 8 h, hydration temperature (TH) was 90 °C, the desulfurization performance was the best. The most efficient additive in hydration reaction was H2C2O4, the calcium conversion rate reached to 73.7% by adding 0.5% H2C2O4. The optimal hydration conditions for quenching magnesium slag/fly ash were also MR = 20, tH = 8 h, and the relationship between fractal dimension and calcium conversion rate was similar to parabolic. The activation energy of this hydration reaction was 72.37 kJ mol− 1. The relationship between hydration degree and calcium conversion rate was a positive correlation in the condition.