Metal Oxide Powder Purification via Halogen Sublimation
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Solution Overview
Problem
Current methods for purifying metal oxide powders, such as using a magnet with a magnetic flux density of 4,000 gauss or more, are insufficient in removing impurities like uranium, iron, and titanium, failing to meet the increasing purity demands of users.
Innovation Solution
A method involving heating metal oxides in the presence of a halogen, specifically chlorine, at controlled temperatures and pressures, with repeated cycles to convert impurities into halides that sublime, thereby achieving high purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a magnet with magnetic flux density of 4,000 gauss or more is used to remove impurities, then magnetizable foreign substances are removed from the metal oxide powder, but the purity level is insufficient to meet user requirements
Solution Approach 1:
The patent changes the purification mechanism from magnetic separation to chemical reaction by introducing halogen gas. The metal oxide powder is heated in the presence of halogen gas (chlorine, bromine, or iodine) at temperatures between 400-1200°C, causing impurities to react with the halogen and form volatile halide compounds that are removed from the powder.
Solution Approach 2:
The patent utilizes phase transition of impurities from solid state to gaseous state through halogenation. Impurities such as iron, titanium, and uranium react with halogen gas to form volatile halide compounds that sublime and are removed from the metal oxide powder, achieving high purity levels.
2Ease of manufacture
If conventional magnetic removal methods are used, then the process is simple, but impurities like uranium, iron, and titanium remain in the powder
Solution Approach 1:
The patent introduces halogen gas as an intermediary substance to facilitate impurity removal. The halogen gas acts as a mediator that reacts with impurities to form removable compounds, enabling the removal of non-magnetizable impurities like uranium, iron, and titanium that cannot be removed by magnetic fields alone.
Solution Approach 2:
The patent replaces the mechanical magnetic separation system with a chemical reaction system. Instead of using magnetic fields to separate impurities, the process uses chemical reactions between halogen gas and impurities to form volatile compounds, thereby removing the limitation of magnetic field-based separation.
3Manufacturing precision
If heating in the presence of halogen is performed, then impurities are converted to halides and removed, but the process requires controlled temperature and pressure conditions
Solution Approach 1:
The patent optimizes temperature parameters to achieve effective impurity removal. By controlling the heating temperature between 400-1200°C, the process ensures that impurities react with halogen gas to form volatile halide compounds while preventing decomposition of the metal oxide powder itself.
Solution Approach 2:
The patent employs a multi-stage periodic process consisting of heating in halogen atmosphere, followed by heating in inert gas atmosphere, and repeated cycles. This periodic action allows for progressive removal of impurities and prevents secondary contamination, achieving high purity levels through repeated treatment cycles.
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 removes impurities like uranium, iron, and titanium, resulting in metal oxide powders with extremely low content rates, meeting the high purity requirements for applications in semiconductor sealing materials and other industries.
Implementation Method 1
heating a metal oxide in the presence of a halogen... such that impurities to be aimed react with a halogen to become halides
Implementation Method 2
convert impurities into halides that sublime, thereby achieving high purity
Implementation Method 3
a heating step in the presence of a halogen, which heats a metal oxide in the presence of a halogen
Data Source
AI summary
A metal oxide powder in which the metal is other than uranium, iron and titanium, and, in the metal oxide powder, the content rate of uranium is 1.0 ppb by mass or less, the content rate of iron is 100 ppm by mass or less in terms of Fe2O3, the content rate of titanium in terms of TiO2 oxide is 8 ppm by mass or less. Included is a method of producing a metal oxide powder which removes impurities from a metal oxide powder so that a metal oxide powder having a high purity can be obtained, and a metal oxide powder produced according to the method.