溶剂萃取-树脂吸附联合脱除盐湖老卤中的微量硼

Removal of micro-amount boron from salt lake brine by solvent extraction-resin adsorption combined method

采用溶剂萃取-树脂吸附联合的方法对青海盐湖卤水中的硼进行了提取和脱除。研究了p H、相比和萃取级数对萃取过程的影响,讨论了萃取后卤水的p H和树脂用量等对吸附过程的影响,考察了D564树脂的吸附等温线和吸附动力学特性,并对反萃和洗脱过程进行了优化。研究结果表明:萃取过程中卤水p H为2时,萃取效果最佳,相比和萃取级数增加至3后继续增加相比和萃取级数对进一步降低卤水中硼浓度的作用并不明显;吸附过程中卤水的p H最佳值为7,吸附动力学数据符合准二级动力学模型,吸附等温线数据符合Langmuir等温吸附模型;当树脂用量为6g/(100m L卤水)时,可直接将一级萃取后卤水中的硼浓度降低至1.0mg/L以下;建议使用0.1mol/L的Na OH溶液作反萃剂,0.5mol/L的HCl溶液作洗脱剂。

A solvent extraction-resin adsorption combined method was developed to recover and remove micro-amount boron from brine of salt lake in Qinghai.The effects of pH,phase ratio,extraction stages on extraction process,and the effect of pH of brine after first stage extraction,resin dosage on boron adsorption were investigated.The adsorption isotherm and kinetics were studied.The stripping and elution process were also optimized.The results showed that best extraction result could be obtained when pH was2.The reduction of boron concentration was not obvious when the phase ratio and extraction stage value were above3.The best pH for boron adsorption from brine was7.The adsorption kinetics and adsorption isotherm data were fitted well with pseudo-second-order rate model and Langmuir model,respectively.The concentration of boron could be reduced to1.0mg/L or less when resin dosage is6g/(100mL brine)using the extraction-adsorption combined method.The proper stripping agent and eluent were0.1mol/L NaOH and0.5mol/L HCl,respectively.