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核技术使用的原材料中,只允许存在痕量稀土,因为稀土中的钐、钆、铕、镝等元素的热中子吸收截面大.在制备核纯铀、钍金属时,需要大量的金属钙作为还原剂.如果不控制其中的稀土杂质量,还原后,稀土必然转移到铀、钍金属中,从而降低核燃料的纯度,甚至达不到核能纯度指标.因而需要检验金属钙中的稀土元素含量.1971年我们曾用D-2EHPA—TBP萃取法建立了钙中稀土化学光谱测定操作规程,该法对钙中重稀土元素能定量回收.
Only the presence of trace amounts of rare earths is allowed in raw materials used in nuclear technology because of the large thermal neutron absorption cross section of elements such as samarium, gadolinium, europium, dysprosium, etc. In the preparation of nuclear pure uranium and thorium metal, a large amount of metallic calcium As a reducing agent.If you do not control the amount of rare earth impurities, after reduction, the inevitable transfer of rare earths to uranium, thorium metal, thereby reducing the purity of nuclear fuel, and even nuclear purity index. So you need to test the content of rare earth elements in metallic calcium In 1971 we used the D-2EHPA-TBP extraction method to establish a procedure for the determination of rare earth elements in calcium, which can be used for the quantitative recovery of heavy rare earth elements in calcium.