以七氟丙烷为介质离心分离碳同位素

Centrifugal Separation of Carbon Isotopes Using Heptafluoropropane as Processing Gas

以七氟丙烷(C3HF7)为分离介质,通过气体离心法研究碳同位素的分离制备。利用国产气体离心机开展单机离心分离实验,通过气体质谱仪分析C3HF7样品,计算不同工况条件下的分离系数和单机分离功率,分离系数可达1.12。在单机实验结果的基础上,采用相对丰度匹配级联(MARC)模型,对富集13 C的生产进行级联计算。选取分离功率最大的实验工况作为计算参数,通过三次级数分别为30、60、75的级联分离,可以将13 C的丰度从天然丰度富集至30%以上。综合考虑单机实验和级联计算的结果,以C3HF7为介质离心分离碳同位素可行。

The demand for stable isotopes has increased in the field of medical diagnosis,biopharming,quantum communication and so on.Natural carbon has two stable isotopes：12 C（98.89%）and 13 C（1.11%）.13 C in high abundance is mainly used in tracer field.For example,13 C can be manufactured in the form of urea for Helicobacter Pylori diagnosis without any radioactivity or toxicity.As much more focus has been paid on safety and health,13 C reveals big advantage over other radioactive tracer isotopes.The radically increased demand for 13 C put forward higher requirements on both the capacity and maximal abundance on 13 C production.Rectification is the only method which has been used for large-scale industrial production of 13 C at present all over the world,while China has not yet mastered the technology to produce 13 C in high abundance under industrial-scale.Considering gas centrifugation method owns the advantages of low energy consumption and large single-stage separation factor,studies on centrifugal separation of carbon isotopes were carried out.Using heptafluoropropane（C3 HF7）as processing gas,single-centrifuge experiments were done based on domestic gas centrifuges.Separation products were analyzed by a MAT-253 gas mass spectrometer.As a result,the separation factor and single-centrifuge separative power under different working conditions were obtained.The single-centrifuge separation factor could reach 1.12.Based on the results of single-centrifuge separation experiments,the working condition with the maximum separative power was selected as the calculation parameters,then cascade calculation of the enrichment of 13 C isotope was conducted by the matched abundance ratio cascade（MARC）.The design parameters of centrifugal cascades for enrichment of13 C were worked out.Through three-time separations by MARC,with stage number of30,60 and 75,respectively,13 C isotope could be enriched from natural abundance to above 30% in abundance.With overall consideration of single-centrifuge experiments and cascade calculation,the feasibility of separating carbon isotopes by gas centrifuge using heptafluoropropane as processing gas has been demonstrated.The study lays a foundation for carbon isotopes production by gas centrifugation method.