Inorganic Chemicals Industry ›› 2022, Vol. 54 ›› Issue (7): 49-54.doi: 10.19964/j.issn.1006-4990.2022-0123

• Research & Development • Previous Articles     Next Articles

Investigation on holding mechanism and removal method of trace calcium in high purity boric acid prepared by esterification method

HE Zhengyan1,2(),LI Changwei1,2,TIAN Peng1,2,BI Shengnan1,2,ZHU Peihan1,2,LI Xinzhu1,2,YE Junwei1,2,NING Guiling1,2()   

  1. 1.State Key Laboratory of Fine Chemicals,Dalian University of Technology,Dalian 116024
    2.Engineering Laboratory of Boric and Magnesic Functional Material Preparative and Applied Technology
  • Received:2022-03-16 Online:2022-07-10 Published:2022-07-14
  • Contact: NING Guiling E-mail:hezhengyan@mail.dlut.edu.cn;ninggl@dlut.edu.cn

Abstract:

Borate esterification is one of the effective approaches for low-cost and large-scale preparation of nuclear power grade and photoelectric grade high-purity boric acid.However,the boric acid obtained by this method always contains trace calcium impurities,which affects the application performance.Combined with the esterification process,the residual mechanism and removal method of trace calcium impurities were discussed.The impurity content and product characteristics in the purified samples were analyzed and characterized by inductively coupled plasma(ICP),X-ray diffraction(XRD) and scanning electron microscope(SEM).The results showed that the content of the residual calcium in esterified boric acid was not significantly dependent on the impurity constituents and their contents of raw boric acid,but it was dependent on the distillation temperature turbulence of borate ester.When an appropriate amount of interfering agent containing lone pair electrons was added during the hydrolysis of borate ester to boric acid,the residual amount of calcium in boric acid could be effectively reduced without introducing other impurities.Based on the experimental results,the possible residual mechanism and removal principle of trace calcium were put forward.

Key words: borate, boric acid, high-purity boric acid, calcium removal, purification

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