Niobium consumption has burgeoned owing to the increasing application of niobium in critical industries, including the aerospace and oil and gas industries. Conventional metallurgical technologies and separation methods for niobium extraction use highly concentrated HF, which is hazardous to both humans and the environment. A solvent extraction system comprising trioctyl tertiary amine (N235) and 4-methyl-2-pentanone (MIBK) that can extract and separate niobium from an oxalate-containing H₂SO₄ solution is proposed in this paper. Niobium solutions tend to contain titanium and iron impurities; therefore, the effects of various conditions on the separation of the three elements were investigated. The extraction mechanism and thermodynamics of the process were also examined. Over 82% niobium was extracted at an organic-to-aqueous phase ratio of 1:1 and the H⁺ concentration of 8.29 mol/L using an organic phase with 50 vol% N235 and 50 vol% MIBK as the extractants at 20 °C. Only 18.4% titanium and 3.35% iron were co-extracted. Two stripping processes, both of which further separated niobium and titanium, are also proposed herein. The possible composition of the niobium-containing extraction complex was [(R₃NH)·NbO(C₂O₄)₂(H₂O)₂], as supported by a Fourier transform infrared spectroscopy (FT-IR) analysis and ultraviolet–visible (UV–vis) spectrophotometry. The extraction mechanism was inferred to be the association of R₃NH⁺ in N235 with the [NbO(C₂O₄)₂(H₂O)₂]⁻ from the acidic niobium-containing solution, and the stripping mechanism was concluded to be anion exchange. The enthalpy change (∆H^o) of the extraction system was −11.0 kJ/mol at 288.15–313.15 K, which indicated that niobium extraction from the H₂SO₄ solution with oxalate using N235 and MIBK was an irreversible exothermic process.

由于铌在关键行业（包括航空航天和石油和天然气行业）中的应用越来越多，铌消费量迅速增长。铌提取的常规冶金技术和分离方法使用高浓度的 HF，这对人类和环境都有害。一种包含三辛基叔胺 (N235) 和 4-甲基-2-戊酮 (MIBK) 的溶剂萃取系统，可从含草酸盐的 H ₂ SO _{4 中}萃取和分离铌本文提出了解决方案。铌溶液往往含有钛和铁杂质；因此，研究了各种条件对三种元素分离的影响。还研究了该过程的提取机理和热力学。在 20 °C 下使用含有 50 vol% N235 和 50 vol% MIBK 的有机相作为萃取剂，以 1:1 的有机相与水相比和8.29 mol/L的 H ⁺浓度萃取超过 82% 的铌. 只有 18.4% 的钛和 3.35% 的铁被共同提取。本文还提出了两种剥离工艺，这两种工艺都进一步分离了铌和钛。含铌萃取配合物的可能组成为[(R ₃ NH)·NbO(C ₂ O ₄ )₂ (H ₂ O) ₂ ]，由傅里叶变换红外光谱 (FT-IR) 分析和紫外-可见 (UV-vis) 分光光度法支持。提取机制被推断为N235中的 R ₃ NH ⁺与酸性含铌溶液中的 [NbO(C ₂ O ₄ ) ₂ (H ₂ O) ₂ ] ^-缔合，得出的剥离机制为做阴离子交换。萃取系统的焓变 (ΔH ^o ) 在 288.15–313.15 K 时为 -11.0 kJ/mol，这表明从 H ₂ SO _{4 中}萃取铌 使用 N235 和 MIBK 的草酸盐溶液是一个不可逆的放热过程。