Method for extracting and separating zirconium and hafnium in nitric acid medium

An extraction and nitric acid technology, applied in the field of purification, can solve the problems of polluted environment, large solvent loss, poor operating workshop environment, etc., and achieve the effects of simple process flow, clean separation process and large extraction capacity

Inactive Publication Date: 2018-06-29
SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there are some disadvantages in the MIBK method: (1) the solubility of MIBK in water is as high as 1.7wt% (it is one of the extraction agents with the highest solubility in water), and the solvent loss is large; (2) it is necessary to use unstable thiocyanic acid (and thiocyanic acid Salt), easily decomposed into toxic decomposition products under acidic conditions, such as hydrogen sulfide, methyl mercaptan and CN - etc., pollute the environment; (3) MIBK has a certain smell, which makes the operating workshop environment poor; ④ MIBK has a low flash point, which is easy to cause fire
It is precisely because of these shortcomings of the MIBK method that its industrial application is limited.
[0006] At present, when diisobutyl ketone (DIBK) is used as the extraction agent, thiocyanic acid or its salts need to be used. Due to the high toxicity of thiocyanic acid or its salts, it is not environmentally friendly in the separation process

Method used

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  • Method for extracting and separating zirconium and hafnium in nitric acid medium
  • Method for extracting and separating zirconium and hafnium in nitric acid medium
  • Method for extracting and separating zirconium and hafnium in nitric acid medium

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Embodiment 1

[0053] A method for separating zirconium and hafnium, the specific steps are as follows:

[0054] (1) Preparation of acidic feed liquid: the water phase is composed of an initial total concentration of zirconium and hafnium ions of 1.5mol / L, wherein the concentration of hafnium ions is about 0.018mol / L, and the acidity of the water phase is 2.87mol / L, (NH 4 ) 2 SO 4 The concentration is 0.8mol / L.

[0055] (2) extractant adopts the mixed organic phase that the DIBK of 90% (v / v) and the Cyanex923 of 10% (v / v) form, first the nitric acid of extractant and equal volume 5.5mol / L is carried out pre-extraction once, then The extraction agent after the pre-extraction is used as the organic phase, the acid feed liquid is used as the water phase, and the control ratio (organic phase: water phase) is 2: 1, and the feed liquid is carried out to single-stage extraction at room temperature, and the mixing time of the two phases is 10 Minutes, the zirconium stays in the water phase to obt...

Embodiment 2

[0078] The organic phase is composed of 90% (v / v) of DIBK, 2% (v / v) of Cyanex921 and 8% (v / v) of isooctane (as a diluent), and pre-mixed with an equal volume of 6.0mol / L Nitric acid pre-extracted once, the water phase composition is the initial total concentration of zirconium and hafnium ions 1.5mol / L, wherein the concentration of hafnium ions is 0.018mol / L, and the acidity of the water phase is 3.0mol / L, (NH 4 ) 2 SO 4 The addition amount is 1.0mol / L, the control ratio is 2:1, single-stage extraction is carried out at room temperature, the two-phase mixing time is 5 minutes, and the raffinate and the loaded organic phase containing hafnium are obtained after phase separation. Re-precipitate with ammonia water to obtain zirconium hydroxide precipitate; carry out back-extraction with 1.0mol / L potassium carbonate on the loaded organic phase, the ratio of washing and back-extraction is 1:2, and the mixing time of the two phases is 5 minutes to obtain zirconium-containing The h...

Embodiment 3

[0081] The organic phase is composed of 90% (v / v) of DIBK, 8% (v / v) of Cyanex923 and 2% (v / v) of sulfonated kerosene (as a diluent), and pre-mixed with an equal volume of 6.0mol / L Nitric acid pre-extracted once, the water phase composition is the initial total concentration of zirconium and hafnium ions 1.5mol / L, wherein the concentration of hafnium ions is 0.018mol / L, and the acidity of the water phase is 3.0mol / L, (NH 4 ) 2 SO 4 The addition amount is 0.8mol / L, the control ratio is 2:1, single-stage extraction is carried out at room temperature, the two-phase mixing time is 5 minutes, and the raffinate and the loaded organic phase containing hafnium are obtained after phase separation. Re-precipitation with ammonia water to obtain precipitation of zirconium hydroxide with less hafnium; back-extract the loaded organic phase with 1.0mol / L sodium carbonate, the ratio of washing and back-extraction is 1:2, and the mixing time of the two phases is 5 minutes. A zirconium-contain...

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Abstract

The invention provides a method for extracting and separating zirconium and hafnium in a nitric acid medium and belongs to the technical field of fine separation of substances. The method mainly comprises the steps as follows: an acidic feed liquid of a zirconium compound is subjected to extraction through a synergistic extraction system consisting of DIBK and phosphonic acid extracting agents, sothat zirconium enters an aqueous phase and hafnium enters an organic phase for separation. No toxic substances are used in the whole process and the purpose of clean production is achieved.

Description

technical field [0001] The invention relates to the technical field of purification, in particular to a method for extracting and separating zirconium and hafnium in a nitric acid medium. Background technique [0002] Zirconium and hafnium are always symbiotic in nature. The content of hafnium in general commercially available zirconium chemicals (m Hf / m (Zr+Hf) ) is less (generally 1% to 3%), and it will have a greater advantage if an extractant that preferentially extracts hafnium is used for its separation. Due to the "lanthanide contraction", the atomic and ionic radii of zirconium and hafnium are basically the same, and their physical and chemical properties are very similar. It is very difficult to separate each other. It is considered to be one of the most difficult elements in the periodic table to separate. However, due to the different nuclear properties of zirconium and hafnium, zirconium has a small thermal neutron absorption cross section, and is widely used...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B3/40C22B34/14C22B3/10
CPCC22B3/10C22B34/14C22B3/409Y02P10/20C22B3/3844C22B7/001C22B7/007
Inventor 徐志高张文杰吴明何正艳何宏杨张蓉
Owner SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES
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