用铅为载体从铀精矿中提取镭
THE EXTRACTION OF RADIUM FROM URANIUM ORE CONCENTRATES USING LEAD AS THE CARRIER
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摘要: 对用铅为载体从铀精矿中提取镭的可能性进行了研究,提出了一套新的提镭工艺流程。 用40%硝酸从铀矿石中浸出铀和镭,在浸出液中加入硝酸铅和硫酸,使镭以硫酸铅-镭形式沉淀,用EDTA溶液将沉淀溶解,调节酸度至pH=4,让硫酸钡-镭选择沉淀。将后者的EDTA溶解液调节酸度后,通过装有SA110×8阳离子交换树脂的柱子进行色层分离。 考察了NH_4~+浓度对离子交换色层分离钡、镭的影响,选定了较好的操作条件。连续进行两次离子交换色层分离,得到含镭210—245毫克/升、钡0.12—0.22毫克/升的硝酸镭溶液。 提出的流程具有工序少、生产周期短、试剂耗量少、回收率高和产品纯度高等优点。Abstract: The possibility for extracting radium from uranium ore concentrates using lead as the carrier has been studied. A process is being developed and demonstrated on a laboratory scale. Uranium ore concentrates are attacked with 40% nitric acid. Pb (Ra) SO4 is precipi- tated by adding lead and sulfuric acid, which is then dissolved in a 120 g/1 solution of EDTA having pH 9.7. The acidity of this solution is adjusted to a pH of 4, and radium is coprecipitated from the solution with barium sulfate. The later is completely dissolved in a 80 g/1 solution of EDTA having pH8.5. The solution is acidified and used as the starting solution for ion-exchange separation.The influence of the NH4+ Concentration on the separation of radium from barium has been investigated. With this in mind, the optimum condition for the separation can be chosen. The pure solution of radium is obtained by only two successive ion-exchange chromatographic separation steps. The radium concentration in the portion of the eluate containing radium is 210-245 mg/1, but that of barium is 0.12-0.22 mg/1. The overall yield of radium is higher than 84%. EDTA and Pb(NO3)2 can be regenerated and retur-' ned to the process. => ' : '