应用电子探针-扫描电镜研究陕西华阳川铀稀有多金属矿床稀土矿物特征

陕西华阳川铀稀有多金属矿床伴生大量的稀土资源，其矿石类型独特、组分复杂，系统的稀土矿物学工作将揭示矿石主要稀土矿物类型、稀土元素赋存状态，进而对矿床开发中稀土元素综合利用及选冶技术提供重要参考。本文在岩相学基础上，利用电子探针、扫描电镜对陕西华阳川铀稀有多金属矿床矿石中的稀土独立矿物与含稀土矿物进行系统研究，在矿石中发现了褐帘石（La₂O₃ 6.49%～7.61%，Ce₂O₃ 11.50%～14.00%）、磷铈镧矿（La₂O₃ 16.30%～21.21%，Ce₂O₃ 32.06%～39.18%）、磷钇矿（La₂O₃ 2.29%～3.58%，Ce₂O₃ 1.89%～2.37%，Y₂O₃ 39.77%～42.80%）、氟碳铈镧矿（La₂O₃ 12.86%～14.20%，Ce₂O₃ 36.67%～39.90%）、褐钇铌矿（La₂O₃ 1.19%～2.11%，Ce₂O₃ 1.29%～2.30%，Y₂O₃ 22.67%～25.88%）等5种稀土独立矿物；同时发现磷灰石、贝塔石、榍石等矿物中稀土元素含量较高。研究表明，该矿床稀土元素以独立矿物（褐帘石、磷铈镧矿、磷钇矿、氟碳铈镧矿、褐钇铌矿）与类质同象（磷灰石、贝塔石、榍石等矿物）两种形式存在，稀土资源以La、Ce轻稀土元素为主，并富含重稀土元素Y。

EMPA-SEM Study on the Rare Earth Minerals from the Huayangchuan Uranium Rare Polymetallic Deposit, Shaanxi Province

BACKGROUND: The Huayangchua polymetallic deposit is a super-large mineral deposit that has economic endowments of uranium and rare earth resources. The deposit is characterized by the unique ore types and complex mineral assemblage. Systematic mineralogical studies can reveal the main rare-earth minerals and the occurrence of REE, providing an important reference for the comprehensive utilization and metallurgical technology of rare earth elements.
OBJECTIVES: To provide new insight for mineralogy using the in-situ observation and analysis technology.
METHODS: The field emission scanning electron microscope (SEM), electron microprobe analysis (EMPA) and energy dispersive X-ray spectrometer (EDS) were used to systematically study ore minerals of the Huayangchuan deposit.
RESULTS: The rare earth elements in the Huayangchuan deposit mainly occurred in two states. Independent rare-earth minerals included allanite (La₂O₃ 6.49%-7.61%, Ce₂O₃ 11.50%-14.00%), monazite (La₂O₃ 16.30%-21.21%, Ce₂O₃ 32.06%-39.18%), bastnasite (La₂O₃ 12.86%-14.20%, Ce₂O₃ 36.67%-39.90%), fergusonite (La₂O₃ 1.19%-2.11%, Ce₂O₃ 1.29%-2.30%, Y₂O₃ 22.67%-25.88%), and xenotime (La₂O₃ 2.29%-3.58%, Ce₂O₃ 1.89%-2.37%, Y₂O₃ 39.77%-42.80%). REE also occurred as isomorphism in apatite, pyrochlore and sphene.
CONCLUSIONS: REE occurs as rare-earth minerals in the Huayangchuan deposit, including allanite, monazite, bastnasite, fergusonite and xenotime, as well as isomorphism in apatite, pyrochlore and sphene. The REEs in the Huayangchuan deposit are dominated by light rare earth elements, such as La and Ce, with minor heavy rare earth element Y.