Method for separating zirconium and hafnium

A technology of hafnium compounds and zirconium compounds, which is applied in the field of hafnium compounds and can solve problems such as poor industrial availability

Inactive Publication Date: 2007-11-07
H C STARCK GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Other methods, such as solvent extraction from HCl solutions of complexes of thiocyanate with methyl-isobutyl ketone or special trialkylphosphine oxides, have especially problems with emissions (cyanides!) or due to Phosphorus-containing compounds (trialkylphosphine oxides) have poor (in some cases no) industrial availability and are thus disadvantageous

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] 37 g of tetrakis(dimethylamino)hafnium having a concentration of 565 ppm wt Zr was completely melted at 45° C. and then kept at 23° C. for 16 hours. The resulting mixture then consisted of 22 g of crystalline phase and 15 g of liquid phase. As analyzed by ICP-OES, the liquid phase contained only 415 ppm wt of Zr, in contrast to the solid phase containing 660 ppm wt of Zr.

[0039] ICP-OES (Inductively Coupled Plasma-Optical Emission Spectroscopy) analysis and methods of its operation are well known to those skilled in the art and are described, for example, in M.C. Wende, M. Luebke, A. Gross, K.-P. Jaeckel, Nachrichten aus der Chemie 52(11), 2004, p.1152-1154, and J. Nolte, CLBChemie in Labor und Biotechnik 51(8), 2000, p.286-292.

Embodiment 2

[0041] 164.7 g of tetrakis(dimethylamino)hafnium containing 0.81 wt% Zr were treated in a similar manner to Example 1. The operation was repeated more than two times on the liquid phase (1) obtained in the first step to obtain phases (2) and (3). The liquid phase contained the following amounts of Zr (measured by ICP-OES method):

[0042] (1) 0.77wt%

[0043] (2) 0.69wt%

[0044] (3) 0.59 wt%,

[0045] The above shows that the purification effect gradually increases (the Zr content gradually decreases). Before each step of liquid phase separation, relative to the total amount of amino compounds, the purified liquid phase yields are: step (1) 72%, step (2) 80%, step (3) 57%.

Embodiment 3

[0047] Here the cumulative effect of Zr in the crystallized, removed part is shown. Starting from 95 g of tetrakis(dimethylamino)hafnium containing 0.72 wt% Zr, 26.9 g, 19.5 g and 26.0 g of liquid phase were removed step by step by repeated partial melting at about 30°C and crystallization again at 0°C. The last remaining crystalline phase (21.8 g) contained 1.3 wt% Zr.

[0048] The combined liquid phases were treated twice in the same manner as in Example 2 to remove the higher melting point solids containing more Zr contaminants. Finally, at about 23°C, the remaining liquid phase (19.4 g) contained 0.57 wt% Zr.

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PUM

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Abstract

The present invention provides a new process for separating zirconium and hafnium compounds, in particular to remove traces of zirconium compounds from hafnium compounds, using fractional crystallisation, as well as hafnium compounds obtainable in accordance with this process.

Description

technical field [0001] The invention provides a new method for separating zirconium compound and hafnium compound, especially a method for removing trace zirconium compound from hafnium compound by adopting fractional crystallization method, and the hafnium compound obtained according to the method. Background technique [0002] Hafnium formed in nature is always together with zirconium. For example, hafnium exists in a relatively small proportion in zirconia and zirconia ores, about 2-7wt%. Due to their extremely similar chemical properties, especially due to the so-called lanthanide contraction, zirconium and hafnium are among the most difficult elements in the periodic system to separate. [0003] The separation of zirconium and hafnium is technically important because their nuclei have very different neutron capture cross-sections, which is important for metals used in nuclear power plants. Since zirconium has a very low neutron absorption and its main use is as claddin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F7/00
CPCC07F7/006B01D9/004C07F7/003B01D9/00B01D9/02C01G27/00
Inventor K·鲁特G·怕辛S·基克迈耶
Owner H C STARCK GMBH
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