提高Nb2O5中Ta2O5光谱分析的灵敏度

由于Ｎｂ２Ｏ５与Ｔａ２Ｏ５物理、化学性质相似，主体Ｎｂ２Ｏ５对Ｔａ分析线强度干扰很大。因此，Ｎｂ２Ｏ５中光谱测定Ｔａ２Ｏ５的灵敏度很差，为了提高Ｔａ分析线强度，通常的光谱条件选择是无效的。实验表明在旋流气室中，采用高含量Ａｒ的（Ａｒ、Ｏ２）控制气氛电弧激发，提高了Ｎｂ２Ｏ５中Ｔａ２Ｏ５的光谱分析灵敏度。然而，由于Ｎｂ２Ｏ５在高温下易于被碳还原，虽然用Ｓｔａｌｌｗｏｏｄ喷咀可以改善蒸发，减慢样品还原

Improvement in the Detection Limit of Tantalumin Spectrographic Determination of TantalumPentoxide in Niobium Pentoxide

Since Nb_2O_5 and Ta_2O_5 have very similar chemicaland pysical characteritics,the influence of matrixNb_2O_3 on Ta_2O_5 results in low sensitivity for tantalum.To increase the intensity of Ta spectral lines,it isineffective by changing operation conditions in normalway.It is experimentally shown that the analyticalsensitivity of Ta_2O_5 in Nb_2O_5 can be increased by useof a controlled atmosphere which includes a largeamount of Ar and small amount of O_2 and flowsthrough cyclone chamber. However,in this case theevaporation of sample is depressed due to reduction ofNb_2O_5 into involatile carbide. Although the evaporationcan be improved by Stallwood jet,it is preferred to use controlled N_2 atmoosphere -D.C. are excitationsystem to facilitate the evaporation. With thisexcitation system,the evaporation rate of the sampleis faster than the reduction rate of samole in theelectrode cave. In this way the analytica sensitivity ofTa_2O_5 in Nb_2O_5 is 5 times higher than that in themixed atmosphere of Ar and O_2,and 100 times higherthan that in air.