Development of a multiple continuous-mode gas extraction and purification system from rocks and minerals

为了开发一种气体提取和净化系统，使我们能够在实验过程中不受任何二次污染地从岩石和矿物中脱气稀有气体和挥发性元素，我们对各种脱气方法进行了检查，如电阻加热、激光烧蚀和破碎方法，并试图将它们结合起来。在钽电阻加热法中，脱气不仅发生在塔炉本身，而且由于加热也会发生在塔炉附近。因此不容易得到很低的空白水平。我们测试了用线圈加热器加热的方法，在几V， 10 a左右的条件下，加热温度可达2000℃左右。由于只有盘管加热器达到高温，所以有可能得到很低的空白水平。然而，问题仍然存在，即没有找到支持和交换样品的适当方法，也没有常规使用。激光烧蚀法与Ta电阻加热法相比，可使样品的空白水平降低两个数量级。在这种情况下，由于脱气量非常低，可用样品有限，这是一个问题。研制了几种破碎装置，并对破碎效率进行了检验。我们研制了一种破碎设备，破碎效率达90%以上。我们进一步计划将这种系统附加到ta电阻加热炉的顶部，并在不直接暴露于大气的情况下转移粉碎的样品。通过将该系统与激光烧蚀系统相结合，我们展示了多连续模式气体提取和净化系统的可能性。

To develop a gas extraction and purification and purification system which enables us to degas noble gases and volatile elements from rocks and minerals without any secondary contamination during the experimental procedures, we have performed to check each degassing method suc has resistance-heating, laser-ablation and crushing methods and tried to combine them.Concerning the Ta resitance-heating method, degassing occurs not only from the Ta furnace itself but also from the nearby areas due to heating. Hence it is not easy to get very low blank level. We examined the heating method by using coil-heater, which could give a temperature up to about 2,000℃ with the condition of a few V and around 10 A. Since only the coil-heater reaches a high temperature, it is possible to get very low blank level. The problem remains, however, that no appropriate way has been found concerning the support and exchange of samples and has not been used routinely.Laser-ablation method could heat samples with lower blank level with the two orders of magnitude compared with those by using the Ta resistance heating method. It is a problem that available sample is limited due to the very low amount of gases degassed in this case. We have developed several kinds of crushing apparatuses and examine the efficiency of crushing. We have developed a crushing apparatus which has the crushing efficiency of more than 90%. We have further planned to attach such system to the top of the Ta-resistance heating furnace and transfer crushed samples with no direct exposition to the atmosphere. By combining this system with the laser-ablation system we have shown a possibility of multiple continuous-mode gas extraction and purification system.