Method for separating praseodymium and neodymium through liquid-liquid-liquid three-phase external push-pull system

A system and three-phase technology, applied in chemical instruments and methods, improvement of process efficiency, inorganic chemistry, etc., can solve problems such as inability to separate, inability to separate with praseodymium and neodymium, and inability to obtain a three-layer liquid phase coexistence system, to achieve The effect of high separation coefficient and wide application range

Inactive Publication Date: 2019-05-10
UNIV OF SCI & TECH BEIJING
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  • Abstract
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AI Technical Summary

Problems solved by technology

However, this method can still only separate light, medium, and recombined rare earth elements in groups according to the principle of "quadrate effect", and cannot separate adjacent rare earth element pairs in the same group.
In addition, the phase formation behavior of the three-phase system is difficult to control, and the reaction conditions (such as equilibrium water phase acidity or salt concentration, etc.) need to be strictly controlled to avoid miscibility between the hydrophobic ionic liquid and the polymer two-phase system, otherwise no Stable three-layer liquid phase coexistence system, unable to achieve three-phase separation of rare earth ions
[0008] At present, most of the published reports on the liquid-liquid-liquid three-phase extraction and separation of rare earth elements focus on the group separation of rare earth element ions, and there are no related reports on the separation of the same group of adjacent rare earth elements with similar properties. In the separation of praseodymium and neodymium

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Dissolve the oxides of praseodymium and neodymium in 100mL of nitric acid solution with a concentration of 0.1mol / L, and prepare a mixed aqueous solution containing praseodymium and neodymium ions (the initial concentration of praseodymium ions is 30mmol / L, and the initial concentration of neodymium ions is 10mmol / L). At room temperature, add sodium nitrate, the ratio of the added molar amount to the molar amount of praseodymium ions in the initial aqueous solution is 200:1, adjust the pH value of the mixed aqueous solution to 1, and mix thoroughly. Then, 20 g of tributylmethylammonium nitrate was added to the mixed aqueous solution, and after being thoroughly mixed at room temperature, the phases were separated by centrifugation to obtain an ionic liquid two-phase aqueous system in which upper and lower liquid phases coexist. Then, add the n-dodecane solution of 10mL P507 to this ionic liquid two-phase aqueous system, the volume percent of P507 in the n-dodecane solutio...

Embodiment 2

[0043] Dissolve the oxides of praseodymium and neodymium with 100mL of hydrochloric acid aqueous solution with a concentration of 0.1mol / L, and prepare a mixed aqueous solution containing praseodymium and neodymium ions (the initial concentration of praseodymium ions is 10mmol / L, and the initial concentration of neodymium ions is 30mmol / L). At room temperature, add lithium nitrate, the ratio of the added molar amount to the molar amount of neodymium ions in the initial aqueous solution is 300:1, adjust the pH value of the mixed aqueous solution to 3, and mix thoroughly. Then, 40 g of 1-ethyl-3-methylimidazolium tetrafluoroborate was added to the mixed aqueous solution, mixed thoroughly at room temperature and then centrifuged to separate phases to obtain an ionic liquid two-phase aqueous system in which upper and lower liquid phases coexist. Then, add 3mL of n-octane solution of P204 to this ionic liquid two-phase aqueous system, the volume percentage of P204 in n-octane soluti...

Embodiment 3

[0045]Dissolve the oxides of praseodymium and neodymium with 100mL of nitric acid aqueous solution with a concentration of 0.1mol / L, and prepare a mixed aqueous solution containing praseodymium and neodymium ions (the initial concentration of praseodymium ions is 100mmol / L, and the initial concentration of neodymium ions is 100mmol / L). At room temperature, add ammonium nitrate, the ratio of the added molar amount to the molar amount of praseodymium ions in the initial aqueous solution is 60:1, adjust the pH value of the mixed aqueous solution to 2, and mix thoroughly. Then, 10 g of tributylmethylammonium nitrate was added to the mixed aqueous solution, and after being thoroughly mixed at room temperature, the phases were separated by centrifugation to obtain an ionic liquid two-phase aqueous system in which upper and lower liquid phases coexist. Then, add the n-dodecane solution of 5mL Cyanex272 to this ionic liquid two-phase aqueous system, the volume percent of Cyanex272 in n...

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Abstract

The invention relates to a method for separating praseodymium and neodymium through a liquid-liquid-liquid three-phase external push-pull system. Inorganic nitrate is added into a mixed aqueous solution containing praseodymium and neodymium ions, the pH value of the mixed aqueous solution is adjusted to 1-4, then water-soluble room temperature hydrophilic ionic liquid is added, mixing is carried out, and an upper and lower two-layer liquid phase coexisted ionic liquid aqueous two-phase system is obtained; and an alkane solution containing an organic phosphorus extracting agent is added, mixingis carried out, and an upper, middle and lower three-layer liquid phase coexisted three-liquid phase system is obtained. Uppermost-layer organic phase extracting praseodymium and neodymium ions havethe positive order complexing effect, the middle-layer ionic liquid phase extracting praseodymium and neodymium ions have the inverted order complexing effect, and the two parts form the external push-pull system. In the finally-obtained three-liquid phase coexisted system, praseodymium ions are enriched in an ionic liquid middle phase, and neodymium ions are enriched in an organic upper phase, sothat praseodymium and neodymium push-pull extraction separation is achieved. The method is wide in application range, can simultaneously extract and separate the praseodymium and neodymium ions, andis high in praseodymium and neodymium seperating coefficient.

Description

technical field [0001] The invention belongs to the technical field of solvent extraction and separation of rare earth elements, in particular to a method for separating praseodymium and neodymium by a liquid-liquid-liquid three-phase external push-pull system. Background technique [0002] Praseodymium and neodymium are the most difficult pair of adjacent rare earth elements in the light rare earth group. Due to the extremely similar chemical properties of the two, it is very difficult to extract and separate praseodymium and neodymium using the traditional oil / water two-liquid phase system. In the actual production process, it is often necessary to combine various methods such as solvent extraction, ion exchange, and chromatographic separation to obtain a single high-purity praseodymium and neodymium product. The process is complicated and the cost is high. [0003] Most of the publicly reported methods for solvent extraction and separation of praseodymium and neodymium s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C22B3/38C22B3/40C22B59/00C01F17/00
CPCY02P10/20
Inventor 黄焜孙盼
Owner UNIV OF SCI & TECH BEIJING
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