An investigation on hydrofluoric (HF) acid-free extraction for niobium oxide (Nb2O5) and tantalum oxide (Ta2O5) from columbite/tantalite concentrates using alkali reductive roasting
An investigation on hydrofluoric (HF) acid-free extraction for niobium oxide (Nb2O5) and tantalum oxide (Ta2O5) from columbite/tantalite concentrates using alkali reductive roasting
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DOI：
10.1016/j.mineng.2021.107183
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发表时间：
2021-09-13
影响因子：
4.8
通讯作者：
Jha, Animesh
中科院分区：
文献类型：
--
作者：
Ghambi, Steven;Sanchez-Segado, Sergio;Jha, Animesh
钽、铌及其氧化物是高温合金和电子器件的重要前驱体材料。从矿物中提取钽和铌的主要湿法冶金萃取技术是用氢氟酸（HF）消化精矿，然后用溶剂萃取作为氧化物分离和纯化步骤。另一方面，溶剂萃取会释放有机溶剂，这些有机溶剂在提取过程中通过自然蒸发不可逆地损失掉。本研究提出了一种提取和精炼铌精矿（Ta2O5含量为29%，Nb2O5含量为16%）的新工艺。在800 ~ 950℃的温度范围内，用碳和碱对精矿进行还原，使精矿中的氧化铁以金属铁的形式还原和磁分离。剩余残渣富含焙烧过程中形成的碱络合物（如钽酸钠和铌酸钠），通过草酸浸出回收为Nb2O5和Ta2O5氧化物的纯化混合物，然后进行硫酸氢钠焙烧。
Tantalum, niobium, and their oxides are important precursor materials, essential for high-temperature alloys and electronic devices. The primary hydrometallurgical extraction technique to extract tantalum and niobium from minerals involves hydrofluoric acid (HF) digestion of the concentrates, followed by solvent extraction as an oxide separation and purification step. Solvent extraction, on the other hand, releases organic solvents which are lost irreversibly via natural evaporation during the process. This research demonstrates a novel chemical process for the extraction and refining of columbite and tantalite concentrates (29% Ta2O5 and 16% Nb2O5). In this process, the concentrates are reduced using carbon and alkali in the temperature range of 800-950 degrees C, which helps in reducing and magnetically separating the iron oxides present in the concentrates as metallic iron. The remaining residue is rich in alkali complex (e.g., sodium tantalates and niobates) formed during the roasting process which was reclaimed as a purified mixture of oxides of Nb2O5 and Ta2O5, by using oxalic acid leaching, followed by sodium bisulphate roasting.