Abstract: Single drop technique is a good method for studying mass transfer in solvent extraction because of its accurate results and simple equipment.The mass transfer coefficient of forward extraction of boric acid from salt lake brine by 2-ethyl-1，3-hexanediol in toluene was investigated.The result shows that the mass transfer coefficient increases with the increasing of temperature and initial concentrations of 2-ethyl-1，3-hexanediol in the organic phase and boric acid in aqueous phase.The model of mass transfer coefficient was established with two-film theory model by considering the modified correlation of mass transfer coefficient.The average relative error of calculated and experimental value of the model was 7.59%，which showed that the results were in good agreement with experimental values.The model can be used to design and scale boric acid extraction process by 2-ethyl-1，3-hexanediol-toluene.

Key words: 2-ethyl-1, 3-hexanediol；boric acid；mass transfer coefficient；two-film theory

摘要： 单液滴法因其测量结果精确与实验设备简单等优点广泛应用于萃取过程中的传质研究。应用此方法研究了硼酸在2-乙基-1，3-己二醇-甲苯/卤水体系中的传质系数。结果表明：传质系数随着有机相2-乙基-1，3-己二醇浓度、卤水相硼酸浓度及温度的增加而增大。通过双膜传质理论分析，并引入修正的传质系数关联式，将双膜传质模型应用到此萃取体系中，建立了新的针对此体系的传质系数模型。新模型的计算值与实验值的平均相对误差为7.59 %，两者吻合良好，因此，该模型可用于2-乙基-1，3-己二醇-甲苯体系萃取硼酸过程的设计与放大。

关键词: 2-乙基-1, 3-己二醇；硼酸；传质系数；双膜理论