Towards sustainable processing of columbite group minerals: elucidating the relation between dielectric properties and physico-chemical transformations in the mineral phase.
Towards sustainable processing of columbite group minerals: elucidating the relation between dielectric properties and physico-chemical transformations in the mineral phase.
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DOI：
10.1038/s41598-017-18272-3
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发表时间：
2017-12-21
影响因子：
4.6
通讯作者：
Jha A
中科院分区：
文献类型：
--
作者：
Sanchez-Segado S;Monti T;Katrib J;Kingman S;Dodds C;Jha A
由于使用氢氟酸（HF），当前提取钽和铌的方法对人类和环境构成严重威胁。铌和钽金属粉末和五氧化物广泛用于节能设备和部件。然而，目前铌和钽金属及氧化物的加工方法能源效率低下。用于能源应用的材料及其低效加工之间的这种二分法是探索提取这两种氧化物的新方法的主要动机，研究用碳酸氢钠碱焙烧含铌钽矿物期间形成的反应产物的微波吸收特性。高温介电测量的实验结果表明，在 700°C 以上的温度下，由于形成 NaNbO3-NaTaO3 固溶体，介电性能值呈指数增长。对焙烧反应过程中介电性能演变的研究是支撑设计新的微波辅助高温工艺的机制的关键特征，该工艺用于从剩余矿物晶格中选择性分离铌和钽的氧化物。
Current methodologies for the extraction of tantalum and niobium pose a serious threat to human beings and the environment due to the use of hydrofluoric acid (HF). Niobium and tantalum metal powders and pentoxides are widely used for energy efficient devices and components. However, the current processing methods for niobium and tantalum metals and oxides are energy inefficient. This dichotomy between materials use for energy applications and their inefficient processing is the main motivation for exploring a new methodology for the extraction of these two oxides, investigating the microwave absorption properties of the reaction products formed during the alkali roasting of niobium-tantalum bearing minerals with sodium bicarbonate. The experimental findings from dielectric measurement at elevated temperatures demonstrate an exponential increase in the values of the dielectric properties as a result of the formation of NaNbO3-NaTaO3 solid solutions at temperatures above 700 °C. The investigation of the evolution of the dielectric properties during the roasting reaction is a key feature in underpinning the mechanism for designing a new microwave assisted high-temperature process for the selective separation of niobium and tantalum oxides from the remainder mineral crystalline lattice.
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