Inorganic Chemicals Industry ›› 2025, Vol. 57 ›› Issue (10): 64-74.doi: 10.19964/j.issn.1006-4990.2024-0683

• Research & Development • Previous Articles     Next Articles

Study on crystallization process and kinetic of macallisterite in concentrated MgCl2-xNa2yB2O3-H2O solution

HU Zhenrong1,2,3(), ZHANG Manman2,3, SHI Chenglong1(), PENG Jiaoyu2,3(), ZHOU Yannan2,3, DONG Yaping2,3, LI Wu2,4   

  1. 1. School of Chemistry and Materials Science,Qinghai Minzu University,Xining 810007,China
    2. Key Laboratory of Green and High-end Utilization of Salt Lake Resources,Qinghai Engineering and Technology Research Center of Comprehensive Utilization of Salt Lake Resources,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining 810008,China
    3. Qinghai Engineering and Technology Research Center of Comprehensive Utilization of Salt Lake Resources,Xining 810008,China
    4. Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province,Xining 810008,China
  • Received:2024-12-17 Online:2025-10-10 Published:2025-07-17
  • Contact: SHI Chenglong, PENG Jiaoyu E-mail:huzr2023@163.com;qhmuscl@126.com;pengjy@isl.ac.cn

Abstract:

Magnesium borate is an important boron-containing raw material in the production of alkali-free glass fiber and ceramics.To address issues such as slow reaction rates,low yields,and high costs in the laboratory synthesis of the hydrated magnesium borate(e.g,macallisterite) for glass applications,a study was conducted on the crystallization process and kinetics of macallisterite in the concentrated salt solutions of MgCl2-xNa2yB2O3-H2O.Firstly,based on MgCl2·6H2O,NaOH and H3BO3 as raw materials,the response surface methodology(RSM) was used to design and optimize the crystallization process conditions of macallisterite,and a crystallization yield prediction model was established.Secondly,based on the theory of crystal growth diffusion,the crystallization mechanism and kinetics of macallisterite were studied,and the crystallization rate equation was obtained.Finally,based on the comprehensive utilization strategy of boron and magnesium resources in salt lakes,the old brine saturated with magnesium chloride was used as raw matrerials to synthesize the macallisterite.The results showed that the predicted boron crystallization yield was 80.56% in B2O3 according to the RSM model,and the experimental value was 81.58% with a relative error of 1.25%.It indicated that the model was reliable and the crystallization yield was improved.The growth mechanism of the macallisterite was the multi-nucleus controlled crystal surface growth model of MA-2,and the crystallization rate was significantly increased.The crystallization yield of the macallisterite synthesized from the old brine was more than 74%,which was lower than that of the optimization experiment.The main reason was due to the decrease in boron concentration and the different mechanisms by which coexisting SO42- ions affect the multi boron species in the solution.The above research not only provided technical support for the industrial production of hydrated magnesium borate for glass,but also provided new ideas for the comprehensive utilization of boron and magnesium resources in salt lake brine.

Key words: macallisterite, response surface methodology, crystallization process, kinetics, salt lake brine

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