以七氟丙烷为介质离心分离碳同位素

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¹³C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¹³C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。

Centrifugal Separation of Carbon Isotopes Using Heptafluoropropane as Processing Gas

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: ¹²C (98.89%) and¹³C (1.11%).¹³C in high abundance is mainly used in tracer field. For example, ¹³C 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,¹³C reveals big advantage over other radioactive tracer isotopes. The radically increased demand for¹³C put forward higher requirements on both the capacity and maximal abundance on¹³C production. Rectification is the only method which has been used for large-scale industrial production of¹³C at present all over the world, while China has not yet mastered the technology to produce¹³C 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 (C₃HF₇) 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 of¹³C isotope was conducted by the matched abundance ratio cascade (MARC). The design parameters of centrifugal cascades for enrichment of¹³C were worked out. Through three-time separations by MARC, with stage number of 30, 60 and 75, respectively, ¹³C 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.