A Raman Investigation on the Boron form Occurring in Salt Lake Brine during Evaporation

摘要：

　　Boron resources are abundant in the Da Qaidam Salt Lake of the Qaidamu basin in China,which has generated significant attention due to the presence of polyborate species in brine from this lake.In this study,Raman spectroscopy was used to investigate the existing form of boron in brine during evaporation.MgO·2B2O3-H2O,MgO·2B2 O3-MgCl2-H2O,and MgO·2B2O3-MgSO4-H2O solutions were also studied to determine the influence of boron concentration,pH,and electrolytes on the borate speciation from brine.The mononborates B(OH)3 and B(OH)4-were found to be the only forms present in natural salt lake brine.Brine evaporation promoted the formation of the polyborate anions B3O3(OH)4-,B5O6(OH)4-,and B6O7(OH)62-and also promoted the disappearance of the B(OH)4-ion from brine at boron concentrations of more than 11g/L B2O3.The pentaborate ion B5 O6(OH)4-was sensitive to the solution pH and appeared only at pH values less than 8.0.Meanwhile,the hexaborate ion B6 O7(OH)62-was observed to be more dependent on the electrolyte magnesium chloride due to its special properties,such as promoting boron accumulation,lowering solution pH,and also its strong affinity for water molecules,which were all beneficial for the polymerization of borate ions in brine.Interaction mechanisms between polyborate anions during evaporation are also proposed herein.ake;evaporation;polyborate species;interaction mechanism.

关键词： Raman spectrum Da Qaidam Salt Lake evaporation polyborate species interaction mechanism

作者: PENG Jiao-yu CHEN Jing WANG Xing-peng DONG Ya-ping LI Wu

作者单位: Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Inst Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Inst Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Inst

会议类型: 国际会议

会议名称: 36th International Conference on Solution Chemistry (36ICSC)(第36届国际溶液化学大会)

会议地点: 西宁

会议语种:英文

页码: 85-94

在线出版日期: 2019-08-05（万方平台首次上网日期，不代表论文的发表时间）