白云鄂博主矿矿石中稀土总含量与能谱强度相关性分析

Analysis of the Correlation between Total Rare Earth Content and Energy Spectrum Intensity for the Bayan Obo Main Ore Body

通过手持γ能谱仪测定了白云鄂博主矿126个块状岩矿石样品的能谱总量与U、Th、40K的含量,通过ICP-MS的方法测定126个粉末样品的Th元素与稀土元素的含量,选取其中18个粉末样品进行高纯锗γ能谱仪测试钍含量,分析对比不同检测方法所测得的Th元素、稀土元素含量之间的相关关系与不同测试方法对所测得的Th元素含量的影响。从数据分析中我们可以发现,白云鄂博矿石中能谱的总强度与γ能谱仪所测得Th的含量呈正相关,U、40K对能谱的总强度贡献较低,不存在相关性。在另外选取的18个矿石样品中通过手持γ能谱仪与高纯锗γ能谱仪所测试的Th元素含量与通过ICP-MS方法测定的Th元素含量都具有很好的相关性,但是在钍含量低于0.05%的时候与手持γ能谱仪所测钍含量相关性较差,同时发现高纯锗γ能谱仪测试精度更高。另外通过分析发现,虽然在白云鄂博矿床中Th元素主要以类质同象方式赋存于稀土矿物中,但是不论是通过ICP-MS测定的Th元素含量还是通过γ能谱仪测定的Th元素含量,二者与稀土元素含量都没有明显的相关性,另外虽然手持γ能谱仪测定钍元素含量的精度相较于化学法与高纯锗γ能谱仪较低,但是在野外工作中依然可以作为一种高效快速的半定量检测手段。

The total energy spectrum and U,Th and 40K contents of 126 massive rock ore samples from Bayan Obo Main Ore Body were determined by handheldγenergy spectrometer,the contents of Th and rare earth elements of 126 powder samples from the ore body were determined by ICP-MS,then Th contents in 18 selected powder samples were determinate by highpurity germaniumγenergy spectrometer.The correlation between the content of Th element and rare earth element measured by different test methods was analyzed,and the influence of different test methods on the content of Th element was investigated.The results show that the total intensity of energy spectrum in Bayan Obo Main Ore Body is positively correlated with the content of Th measured byγspectrometer,but not with U and 40K due to its small contribution to the total intensity of energy spectrum.Th contents in other 18 selected ore samples measured by handheldγenergy spectrometer and high-purity germaniumγenergy spectrometer have good correlation with Th content measured by ICP-MS,but have poor correlation with the Th content measured by handheldγenergy spectrometer,but when the thorium content is lower than 0.05%,high-purity germaniumγenergy spectrometer is found higher testing accuracy.In addition,through analysis,it is found that although Th element mainly occurs in rare earth minerals in the form of isomorphism in the Bayan Obo deposit,correlation of the content of Th element measured by ICP-MS or the content of Th element measured byγspectrometer is not obvious with the content of rare earth element.Besides,precision accuracy of handheldγenergy spectrometer is lower than chemical method and high-purity germaniumγenergy spectrometer for thorium element analysis,but it can still be used as an efficient and fast semi-quantitative detection method in field work.