High-Purity Erbium Manufacturing via Vacuum Distillation

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Solution Overview

Problem

Current methods fail to efficiently and stably purify erbium, which has a high melting point and vapor pressure, making it difficult to refine in a molten metal state, and often result in insufficient oxygen reduction and impurity removal.

Innovation Solution

A method involving the mixing of crude erbium oxide with a reducing metal, followed by heating in a vacuum to distill and melt the mixture in an inert atmosphere, achieving high-purity erbium with reduced oxygen content and minimal impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional refining methods are used for erbium, then the processing is simpler, but the purification efficiency is insufficient and oxygen content remains high

Engineering Contradiction:
Improvepurification efficiencyVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies inert atmosphere by conducting the refining process in a vacuum environment (10^-3 to 10^-6 Pa) and using an inert gas (argon or nitrogen) during the melting step. This prevents erbium from reacting with oxygen during processing, achieving oxygen content of 200 wtppm or less while maintaining a manageable process flow.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent utilizes phase transitions of erbium oxide and erbium metal through controlled heating and cooling cycles. The material transitions from solid erbium oxide to gaseous erbium vapor during vacuum distillation, then condenses back to solid high-purity erbium, enabling effective separation from impurities.

Inventive Principle:
Principle #36Phase transitions

2Manufacturing precision

If erbium is refined in molten metal state, then the refining process is simpler, but erbium oxidizes easily and high purity cannot be achieved

Engineering Contradiction:
Improveerbium purityVSAvoidrefining difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent prevents oxidation by conducting melting and solidification in an inert atmosphere (argon or nitrogen gas). This allows the erbium to be processed in molten state without reacting with oxygen, achieving purity of 4N or higher while maintaining ease of manufacture.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent controls the oxygen partial pressure and atmosphere composition parameters during processing. By maintaining oxygen partial pressure below 10^-3 Pa during vacuum distillation and using inert gas during melting, the process prevents oxidation while enabling effective purification.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If vacuum distillation is used to reduce oxygen content, then oxygen elimination is improved, but the process requires high vacuum conditions and becomes more complex

Engineering Contradiction:
Improveoxygen contentVSAvoidvacuum system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent utilizes the phase transition of erbium from solid to vapor and back to solid through controlled heating and cooling in vacuum. This phase change mechanism enables efficient oxygen elimination through distillation while using a relatively simple vacuum system operating at 10^-3 to 10^-6 Pa.

Inventive Principle:
Principle #36Phase transitions

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 method effectively produces high-purity erbium with a purity of 4N or higher, oxygen content of 200 wtppm or less, and low levels of alkali metals, transition metals, and radioactive elements, suitable for forming high-purity sputtering targets and metal gate films.

Implementation Method 1

crude erbium oxide is mixed with reducing metal, erbium is reduced and distilled to refine the erbium by heating the mixture in a vacuum

Methodology Applied
Scientific EffectThermal reduction: Reduction

Implementation Method 2

erbium is reduced and distilled to refine the erbium by heating the mixture in a vacuum

Methodology Applied
Scientific EffectVacuum distillation: Vacuum Distillation

Implementation Method 3

the distillate is melted in an inert atmosphere to obtain high-purity erbium

Methodology Applied
Scientific EffectInert atmosphere protection: Oxidation

Data Source

PatentEP2383354B1Method for manufacturing high-purity erbium, high-purity erbium, sputtering target composed of high-purity erbium
Publication Date: 2018.03.07 JX NIPPON MINING & METALS CORP

AI summary

Provided are a method for manufacturing high-purity erbium, wherein crude erbium oxide is mixed with reducing metal, erbium is reduced and distilled by heating the mixture in a vacuum, and the distillate is melted in an inert atmosphere to obtain high-purity erbium; and high-purity erbium, wherein the purity excluding rare-earth elements and gas components is 4N or higher and the oxygen content is 200 wtppm or less. An object of this invention is to provide a method of highly purifying erbium, which has a high vapor pressure and is difficult to be refined in a molten metal state, as well as technology for efficiently and stably providing high-purity erbium obtained with the foregoing method, a sputtering target composed of high-purity erbium, and a metal gate film having high-purity erbium as a main component.