含氟硫酸介质中伯胺N1923对Ce（Ⅳ）的萃取

doi:10.19894/j.issn.1000-0518.210088

摘要/Abstract

摘要：

铈（Ce）在轻稀土矿物中常与诸如F等多种其它元素伴生，针对矿物处理过程中得到的同时含有Ce（Ⅳ）和F^－等多组分复杂体系硫酸浸出液，从铈氟综合回收并丰富理论依据的角度出发，对伯胺N1923在含氟硫酸介质中Ce（Ⅳ）的萃取及反萃过程进行了研究。考察了酸度、萃取剂浓度、盐析剂浓度及温度对萃取过程的影响，采用斜率法初步讨论了反应机理。研究表明，预先质子化处理后的伯胺N1923在硫酸介质中可同时萃取Ce（Ⅳ）和F^－，H₂SO₄浓度对Ce（Ⅳ）和F^－的萃取过程无显著影响。Ce（Ⅳ）的萃取率随水相中F^－浓度的增加而增大，萃取过程符合加合机理，其萃合物可表示为CeF（SO₄）_1.5（RNH₃·HSO₄）_1.5。通过考察不同温度下N1923对Ce（Ⅳ）的萃取分配比并计算相应的反应平衡常数及热力学参数，表明萃取过程为自发进行的、熵焓双驱动的放热反应。在含氟体系中，体积分数15%的N1923对Ce（Ⅳ）的饱和负载量为18.85 g／L，同时F^－的负载量为2.00 g／L。通过红外和核磁对萃合物结构分析可知部分萃合物间有多聚作用，硫酸根在萃合物中为双齿配位。此外，萃合物中的Ce（Ⅳ）可被含H₂O₂的硝酸反萃剂有效反萃，反萃率最高为90%，同时F^－几乎可以被完全反萃。

关键词: 伯胺N1923, 铈（Ⅳ）, 氟, 溶剂萃取

Abstract:

Cerium (Ce) usually exists in minerals with accompany of multiple elements, such as fluorine (F). To develop technologies and provide theoretical foundations for comprehensive recovery of Ce and F, the extraction and stripping process of Ce (Ⅳ) by primary amine N1923 in sulfuric acid medium containing fluorine was investigated. The effects of H₂SO₄acidity, extractant concentration, fluorine ion concentration and temperature on the extraction process were comprehensively investigated, meanwhile the extraction mechanism was discussed. It is shown that Ce (Ⅳ) and F^-can be extracted by primary amine N1923 in sulfuric acid medium at the same time, while the H₂SO₄acidity has no significant effect on the extraction. The extraction efficiency of Ce (Ⅳ) increases with the increase of F^-concentration in the aqueous phase and the extraction process conforms to the addition mechanism. Through investigating the extraction performance at varied temperatures, the reaction equilibrium constant and thermodynamic parameter are calculated, revealing that the extraction process is an exothermic reaction driven by both entropy and enthalpy. In the fluorine-containing system, the saturation loading capacity of N1923 (volume fraction 15%) is 18.85 g/L for Ce (Ⅳ) and 2.00 g/L for F^-. Fourier transform infrared (FT-IR) transmission spectroscopy and nuclear magnetic resonance (NMR) spectra of extracted complexes indicate that the complexes are partially polymerized and is bidentatally coordinated in the equilibrium extraction compound. In addition, Ce (Ⅳ) and F^-in the loaded organic phase can be effectively stripped using HNO₃containing H₂O₂as a stripping agent. The stripping rate of Ce (Ⅳ) can reach 90% and the F^-can be almost stripped thoroughly.

Key words: Primary amine N1923, Cerium (Ⅳ), Fluorine, Solvent extraction

中图分类号:

O616

闫宇飞, 陈继, 李凯, 邹丹, 李德谦. 含氟硫酸介质中伯胺N1923对Ce（Ⅳ）的萃取[J]. 应用化学, 2022, 39(02): 307-314.

Yu-Fei YAN, Ji CHEN, Kai LI, Dan ZOU, De-Qian LI. Extraction of Cerium (Ⅳ) by Primary Amine N1923 from Sulfuric Acid Medium Containing Fluorine[J]. Chinese Journal of Applied Chemistry, 2022, 39(02): 307-314.

图/表 12

图1 硫酸浓度对Ce（Ⅳ）和F－萃取的影响

Fig.1 The effect of concentration of H2SO4on the extraction of Ce（Ⅳ）and F－by primary amine N1923c（N1923）＝0.1 mol／L；c（Ce（Ⅳ））＝0.045 mol／L；c（F－）＝0.09 mol／L

图2 F－浓度对伯胺N1923萃取Ce（Ⅳ）的影响

Fig.2 The effect of concentration of fluorine ion on the extraction of Ce（Ⅳ）by primary amine N1923c（N1923）＝0.1 mol／L；c（Ce（Ⅳ））＝0.045 mol／L；c（H2SO4）＝1.0 mol／L

图3 伯胺N1923的浓度对Ce（Ⅳ）和F－萃取的影响

Fig.3 The effect of concentration of primary amine N1923 on the extraction of Ce（Ⅳ）and F－c（H2SO4）＝1.0 mol／L；c（Ce（Ⅳ））＝0.045 mol／L；c（F－）＝0.09 mol／L

图4 浓度对含氟介质中N1923萃取Ce（Ⅳ）的影响

Fig.4 The effect of concentration of on the extraction of Ce（Ⅳ）by N1923 in F－containing H2SO4mediumc（N1923）＝0.1 mol／L；c（Ce（Ⅳ））＝0.045 mol／L；c（F－）＝0.09 mol／L；c（H2SO4）＝1.0 mol／L

图5 温度对含氟介质中伯胺N1923萃取Ce（Ⅳ）的影响

Fig.5 The effect of temperature on the extraction of Ce（Ⅳ）by primary amine N1923 in F－-containing H2SO4mediumc（N1923）＝0.1 mol／L；c（Ce（Ⅳ））＝0.045 mol／L；c（F－）＝0.09 mol／L；c（H2SO4）＝1.0 mol／L

表1 N1923含氟硫酸体系萃取Ce（Ⅳ）的热力学参数

Table 1 Thermodynamic parameters of Ce（Ⅳ）extraction by N1923 in H2SO4media with fluorine

温度	反应平衡常数对数值	吉布斯自由能	熵变	焓变
T／K	log K_ex	ΔG／（kJ·mol^－1）	ΔS／（J·mol^－1·K^－1）	ΔH／（kJ·mol^－1）
293	1.71	－9.60	4.92	－8.16
298	1.69	－9.66	5.02
303	1.67	－9.71	5.11
308	1.65	－9.73	5.09
313	1.63	－9.75	5.09
318	1.60	－9.74	4.97

图6 伯胺N1923在含氟和不含氟体系中对Ce（Ⅳ）和F－的饱和负载量

Fig.6 The loading capacity of Ce（Ⅳ）and F－by primary amine N1923 with／without fluorine in H2SO4 mediaφ（N1923）＝15%；c（H2SO4）＝1.0 mol／L；c（Ce（Ⅳ））＝0.045 mol／L；c（F－）＝0.09 mol／L

图7 N1923硫酸介质中不同体系萃合物的FT-IR

Fig.7 FT-IR spectra of N1923 extracted complexes for different systemin H2SO4medium

表2 N1923硫酸介质中不同体系萃合物的FT-IR特征峰

Table 2 Characteristic FT-IR peaks of N1923 extracted complexes for different system in H2SO4medium

特征峰	伯胺N1923	硫酸酸化N1923	酸化N1923的F萃合物	酸化N1923的Ce（Ⅳ）-F萃合物	酸化N1923的Ce（Ⅳ）-F萃合物
Assignment	N1923	N1923 sulfate	N1923-H₂SO₄-F	N1923-Ce（Ⅳ）	N1923-Ce（Ⅳ）
NH₂伸缩振动	3303，3369	／	／	／	／
ν（NH₂）	3303，3369	／	／	／	／
+NH₃伸缩振动	／	.3020，3423	3063，3462	3085，3140，3462	3087，3141，3461
ν（+NH₃）	／	.3020，3423	3063，3462	3085，3140，3462	3087，3141，3461
NH₂变形振动	800，1612	／	／	／	／
δ（NH₂）	800，1612	／	／	／	／
+NH₃变形振动	／	1505，1600	1525，1625	1524，1623	1524，1622
δ（+NH₃）	／	1505，1600	1525，1625	1524，1623	1524，1622
C—N伸缩振动	1140	1127	1123	1121	1121
ν（C—N）	1140	1127	1123	1121	1121
CH₂弯曲振动	722	722	722	722	722
γ（CH₂）	722	722	722	722	722
伸缩振动	／	641	／	633，648	635，648
ν（）	／	641	／	633，648	635，648
伸缩振动1	／	／	／	945，972	946，971
ν₁（）	／	／	／	945，972	946，971
伸缩振动2	／	447	437	437	438
ν₂（）	／	447	437	437	438
伸缩振动3	／	1056，1197，1221	1041，1174	1034，1090，1168，1222	1034，1090，1168，1222
ν₃（）	／	1056，1197，1221	1041，1174	1034，1090，1168，1222	1034，1090，1168，1222
伸缩振动4	／	590	586	597，617	598，618
ν₄（）	／	590	586	597，617	598，618

图8 伯胺N1923硫酸介质中不同体系萃合物的1H NMR谱

Fig.8 1H NMR spectra of Ce（Ⅳ）-F loaded extracted complexes of N1923

表3 N1923含氟硫酸体系中Ce（Ⅳ）-F萃合物的1H NMR谱的化学位移

Table 3 1H NMR spectra peaks of N1923 extracted complexes for different system in H2SO4medium

结构官能团	伯胺N1923	硫酸酸化N1923	酸化N1923的F萃合物	酸化N1923的Ce（Ⅳ）萃合物	酸化N1923的Ce（Ⅳ）-F萃合物
Structure	N1923	N1923 sulfate	N1923-H₂SO₄-F	N1923-Ce（Ⅳ）	N1923-Ce（Ⅳ）-F
—NH₂	1.03～1.04	Disappear	Disappear	Disappear	appearDis
—NH⁺　3	／	7.34	7.41	6.78～6.89	6.80～6.90
—CH₃	0.85～0.88	0.86～0.88	0.86～0.89	0.85～0.89	0.85～0.89
—CH₂—	1.25	1.25～1.35	1.25～1.36	1.25	1.22～1.25
—CH—NH₂	2.64～2.65	1.61～1.64	1.60～1.66	1.67～1.70	1.67～1.78
H₂SO₄	／	5.60	Disappear	Disappear	Disappear
	／	3.12	3.10	3.29	3.29

图9 反萃液酸度对Ce（Ⅳ）（实线）和F－（虚线）反萃的影响

Fig.9 Effect of H+concentration on the stripping of Ce（Ⅳ）（solid line）and F－（dotted line）from Ce（Ⅳ）-F loaded N1923φ（N1923）＝15%；ρ（loaded-Ce（Ⅳ）in N1923）＝18.62 g／L；ρ（loaded-F in N1923）＝1.95 g／L；Vo∶Va＝1∶2

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