Zirconium Hafnium Tetrachloride Separation via Ionic Liquid Extraction
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Solution Overview
Problem
Current methods for separating zirconium and hafnium tetrachlorides from their mixtures are inefficient, costly, and prone to corrosion, especially at high temperatures, and lack a cost-effective and non-corrosive industrial process for achieving high purity.
Innovation Solution
A liquid-liquid extraction process using an ionic liquid with a non-nucleophilic anion at temperatures below 100°C, which separates zirconium and hafnium tetrachlorides without corrosion, allowing direct recovery as chlorides and achieving enrichment ratios of at least 100:1 by weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid-liquid extraction with methyl ethyl ketone is used to extract aqueous phase, then extraction efficiency is improved, but hydrolysis of chlorides into oxychlorides occurs requiring re-chlorination
Solution Approach 1:
The patent uses anhydrous conditions and non-aqueous solvents (methylene chloride, toluene, hexane) to create an inert environment that prevents hydrolysis of zirconium and hafnium chlorides. This eliminates the need for re-chlorination while maintaining extraction efficiency.
2Device complexity
If extractive distillation of chlorides using alkali chloroaluminate is used, then separation simplicity is improved, but corrosion increases requiring frequent changes of trays and internal components
Solution Approach 1:
The patent changes the temperature parameter from high temperature (360°C) to low temperature (below 100°C) and uses non-aqueous solvents instead of molten salts. This maintains separation effectiveness while eliminating corrosion of distillation column components.
3Manufacturing precision
If fractional crystallization of aqueous fluorozirconate solutions is used, then separation efficiency is improved, but cost increases in terms of labor, investment, reagents, and energy
Solution Approach 1:
The patent extracts zirconium and hafnium chlorides directly from their mixture using liquid-liquid extraction with non-aqueous solvents, eliminating the need for complex fractional crystallization steps, reducing labor, investment, reagent, and energy costs while maintaining high separation efficiency.
4Manufacturing precision
If high temperature processing is used for separation, then separation effectiveness is improved, but corrosion increases and operational complexity increases
Solution Approach 1:
The patent changes the temperature parameter from high temperature to low temperature (below 100°C) and uses non-aqueous solvents, maintaining separation effectiveness through selective solubility differences while eliminating corrosion and simplifying equipment requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process effectively separates zirconium and hafnium tetrachlorides in a single step, avoiding corrosion issues and achieving high purity, making it suitable for industrial-scale production.
Implementation Method 1
liquid-liquid extraction in the strict absence of water at a temperature below 100°C using ionic liquids
Implementation Method 2
aromatic hydrocarbons form arenium complexes with Lewis acids... zirconium and hafnium tetrachlorides... hexamethylbenzene... reacts with zirconium tetrachloride to lead to a binuclear molecular complex... whereas hafnium tetrachloride leads to a binuclear ionic complex
Data Source
Figure 1
AI summary
One of the aspects of the invention is to propose an industrial separation process that is simple, inexpensive and non-corrosive which makes it possible to separate zirconium and hafnium tetrachlorides from mixtures thereof. Another aspect of the invention is to propose a simple industrial process that enables the zirconium/hafnium separation. Another aspect of the invention is to propose a process that makes it possible to produce fractions that are enriched in zirconium and that contain hafnium in trace amounts.