Synthesis Of Magnesium Hydroxide Via Vapor Phase Hydration Of Magnesia And Kinetics Analysis

Magnesite light burning magnesium hydration method is considered as the most advantaged way for magnesium hydroxide materials because of no consumption of acid or alkali and abundant magnesite reserves.However, direct hydration suffered from the poor filterability and agglomerate of the obtained magnesium hydroxide.To solve the problems, National natural science foundation of "Vapor hydrating light calcined magnesia into magnesium hydroxide and their microstructure transformation mechanism and performances, No.21407032" proposed vapor hydrating light calcined magnesia into magnesium hydroxide.Under the premise of completing part of the fund, this paper conducted the synthesis of magnesium hydroxide via vapor phase hydration of magnesia. The relations between various reaction conditions and the hydration conversion ratio were studied. This paper established the related mathematical model, and fulfilled feasibility and economic analysis of this new preparation techno logy.The main contents and results are as follows:(1) The influence of reaction conditions on the hydration conversion ratio. We found that the augment of the activity of magnesium oxide and the hydrating temperature and the decrease of magnesium oxide material granularity and height benefited the hydration by comparing changing trends of the hydration conversion ratio under different conditions respectively. As hydrating time increased, the hydration conversion ratio increased until it stabilized. When the hydration was finished, the hydration conversion rate can reach 93% at less.(2) The kinetics of magnesium oxide vapor phase hydration. We found magnesium oxide hydration was in line with the internal diffusion control of microporous mode by considering magnesia material as a porous lamellar particle and fitting the experimental results data. Finally, we obtained the empirical formula between the hydration conversion ratio and hydration time and height of the material(3) The economic accounting. Furthermore, the paper fulfilled the feasibility and economic analysis of this preparation technology, which provided guidance for the technology industrialization. The paper found the cost of vapor phase hydration was 0.1713 yuan/t less than physical smash from brucite.