back extraction meaning in English

二次回采
反萃取
返提取

Back extraction by hno3 - hf and back extraction by concentrated hnch after lower the concentration of organic phase are studied , the method of back extration by hnorhf can not be used to icp - ms , because some zirconium is hydrolysis when hf is removed by heat . however , the method of back extraction by concentrated nitric acid after lower the concentration of organic phase can be used to icp - ms , the recovery is 93 . 2 % , rsd % is 5 . 24 % , the decontamination factor of uranium is 3 . 2xl04 , the detection limit of zirconium is 0 . 04ng / ml . the method of tta extracting trace zirconium in uranium is firstly used to icp - ms , the result is satisfied , it can be used to determine zirconium in uranic production quickly and veraciously
本文通过研究hno _ 3 - hf反萃和稀释有机相后用浓hno _ 3反萃这两种分离方法，认为hno _ 3 - hf反萃由于在加热去除hf时酸度不易控制，导致锆的部分水解，因而此方法不宜用于icp - ms中，然而稀释有机相后用浓hno _ 3反萃法用于icp - ms测量中，全程回收率为93 . 2 ，相对标准偏差为5 . 24 ，铀的一次去污因子为3 . 2 10 ~ 4 ，锆的测定下限为0 . 04ng / ml ，本文首次将tta萃取分离铀中锆用于icp - ms测量中，结果令人满意，此方法适用于快速、准确测量铀产品中微量锆。