Molten Metal Vessel Alumina Silica Lining Thermal Expansion
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Solution Overview
Problem
Conventional lining materials in molten metal vessels face issues with peeling due to exposure to additives and severe temperature conditions, leading to reduced durability and corrosion resistance.
Innovation Solution
A vessel with a vessel body made of alumina-silica-based material and a protective layer of silicon nitride-alumina-based material, where the alumina content in the vessel body is between 72 to 95 parts by weight and the silicon nitride content in the protective layer follows specific formulas to ensure matching thermal expansion and prevent peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lining materials are used in molten metal vessels, then the vessel can store molten metal, but the lining peels off due to exposure to additives and severe temperature conditions, reducing durability
Solution Approach 1:
The patent uses a composite lining structure consisting of a lower layer made of magnesia-based refractory material and an upper layer made of spinel-forming material (magnesia and alumina). This composite structure combines the high-temperature resistance of magnesia with the chemical stability and low permeability of spinel, preventing peeling while maintaining durability under severe temperature conditions and exposure to additives.
Solution Approach 2:
The patent controls the chemical composition parameters of the lining materials, specifically maintaining magnesia content at 80-95 wt% in the lower layer and forming spinel with specific MgO-Al2O3 ratios in the upper layer. By optimizing these compositional parameters, the lining achieves matched thermal expansion coefficients and chemical stability, preventing peeling and extending service life.
2Object-affected harmful factors
If refractory materials like magnesia and alumina are used to form spinel, then permeation resistance improves, but the lining still peels under severe temperature conditions and exposure to additives
Solution Approach 1:
The patent creates a two-layer composite structure where the lower magnesia-based layer provides high-temperature stability and the upper spinel-forming layer provides chemical resistance and low permeability. The interfacial bonding between layers, achieved through controlled chemical reactions during service, prevents peeling while maintaining permeation resistance against molten metal and additives.
Solution Approach 2:
The patent applies different material compositions to different regions of the lining: the lower layer near the molten metal uses high-magnesia material for thermal stability, while the upper layer uses spinel-forming materials for chemical resistance. This local differentiation of material properties optimizes both permeation resistance and peeling resistance in their respective zones.
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
The solution provides high durability and corrosion resistance to high-temperature molten metals, preventing peeling and extending the lifespan of the vessel by ensuring excellent adhesion and thermal stability.
Implementation Method 1
the material for the protective layer is adjusted to have a silicon nitride content y per 100 total parts by weight of silicon nitride and alumina in such a manner that y applies to the following formulae (1) and (2)... ensuring excellent adhesion and thermal stability
Data Source
AI summary
The invention provides a vessel for molten metal comprising a vessel body formed of an alumina-silica-based material, and a protective layer formed of a silicon nitride- alumina-based material provided on the inner surface of the vessel body, wherein the material for the vessel body is adjusted to have an alumina content x of 72 to 95 parts by weight per 100 total parts by weight of alumina and silica, and the material for the protective layer is adjusted to have a silicon nitride content y per 100 total parts by weight of silicon nitride and alumina in such a manner that y applies to the following formulae: (1) y<−1.1x+128 and (2) y>−0.5x+62.5. The present invention provides a vessel for molten metal having excellent durability and corrosion resistance against hot molten metal.