Inorganic Chemicals Industry ›› 2023, Vol. 55 ›› Issue (4): 45-53.doi: 10.19964/j.issn.1006-4990.2022-0358

• Research & Development • Previous Articles     Next Articles

Boron species transformation and distribution law of Mg(BO22decomposed in LiCl aqueous solution

WEI Fengdan, ZHOU Huan(), XIA Panping, ZHAO Yun   

  1. College of Chemical Engineering and Materials Science,Tianjin University of Science and Technology,Tianjin 300457,China
  • Received:2022-06-13 Online:2023-04-10 Published:2023-04-13

Abstract:

Salt lake brine contains lithium chloride and borate,and boron is one of the main interference factors in the process of recovering lithium from salt lake.In order to know the characteristics of boron species distributed in brine,the distribution law of boron species in lithium chloride aqueous solution was mainly studied.The distribution and concentration state of liquid boron species and their variate behavior with lithium chloride concentration were obtained by studying the solid and liquid boron species produced from the reactions of Mg(BO22 hydrolyzed in a series of aqueous solutions with LiCl concentration from zero to saturation.The results showed that inderite formed when Mg(BO22 was decomposed in water;hungchsaoite and pinnoite but notinderite would generate when Mg(BO22 was decomposed in LiCl aqueous solution with a lower concentration; and only pinnoitewould form in high concentration LiCl aqueous solution.Although Mg(BO22 was coexisted with hydrolyzed solid phase,but it was not a stable salt and could not be in phase equilibrium with the liquid phase.The distribution of liquid boron species was not only related to pH,but also to LiCl concentration.When LiCl concentration was low,B3O3(OH)4- was more than 55% of the total liquid boron.The distribute rate of B3O3(OH)4- was decreased and

B5O6(OH)4- was increased significantly while LiCl concentration was increased.B(OH)4- and B3O3(OH)4- were the boron species with highest concentration in all the LiCl concentration range.B3O3(OH)52-,B4O5(OH)42- and B(OH)4- were the anionic configurations of inderite,hungchsaoite and pinnoite respectively,moreover their concentrations were related to the solubility of the solid phase,while B3O3(OH)4- and B5O6(OH)4- were not corresponding to solid salt,but could maintain higher concentrations.These results and a large number of species data provided an important basis for recognizing the characteristics of boron in brine and quantifying the distribution of boron in brine.

Key words: Mg(BO22, LiCl aqueous solution, raman spectroscopy, solution structure, boron species, chemical reactions

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