Refractory-Metal Composite Barrier for Steelmaking Linings
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Solution Overview
Problem
Metallurgical vessel linings in steelmaking processes are prone to oxidation, leading to the formation of iron oxides that contaminate cast products and compromise the integrity of the refractory linings due to porosity and permeability issues, necessitating enhanced anti-oxidation barrier properties.
Innovation Solution
A refractory composition with a combination of coarse-grain particles (≥150 micrometers) and fine-grain particles, including alumina, magnesia, and titanium dioxide, that infiltrates molten metal to form a refractory-metal composite barrier layer, reducing oxygen transport through the lining by an in situ chemical etching-like effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refractory linings are made chemically inert and physically stable, then they provide good structural integrity and resistance to molten metal, but they exhibit porosity and permeability that allow atmospheric oxygen to transport through to the refractory-melt interface causing oxidation
Solution Approach 1:
The patent applies composite materials by combining refractory particles (alumina, magnesia, spinel) with metallic particles (aluminum, silicon, titanium) to create a refractory-metal composite composition. This composite structure provides both the structural integrity of refractory materials and the anti-oxidation properties of reactive metals that form barrier layers preventing oxygen transport through the lining.
Solution Approach 2:
The patent changes the chemical composition parameters by incorporating reactive metallic particles (aluminum, silicon, titanium) into the refractory matrix. These metallic particles undergo oxidation reactions to form protective oxide layers (alumina, silica, titania) that fundamentally alter the oxygen transport properties of the lining, transforming it from permeable to barrier-forming.
2Stability of the object's composition
If refractory compositions use conventional inert materials, then they maintain chemical stability with molten metal, but they cannot prevent oxidation of molten steel by atmospheric oxygen
Solution Approach 1:
The patent converts the harmful effect of atmospheric oxygen into a beneficial protective layer. The reactive metallic particles (aluminum, silicon, titanium) intentionally react with oxygen to form dense oxide barriers (alumina, silica, titania) that prevent further oxygen penetration and protect the molten steel from oxidation, thereby converting oxygen's harmful role into a protective function.
Solution Approach 2:
The reactive metallic particles serve as intermediaries between the atmospheric oxygen and the molten steel. These particles preferentially react with oxygen to form protective oxide layers that act as a mediator barrier, preventing direct contact between oxygen and the molten steel, thus protecting the steel from oxidation while maintaining chemical stability.
3Quantity of substance
If refractory linings have porosity for permeability, then they allow oxygen transport, but making them denser reduces their ability to form protective barrier layers
Solution Approach 1:
The patent changes the functional parameters of the refractory lining by incorporating reactive metallic particles that undergo phase transformation upon oxidation. The metallic particles transform into dense oxide layers (alumina, silica, titania) with fundamentally different transport properties, converting the lining from oxygen-permeable to oxygen-barrier, while the porous structure facilitates the initial oxidation reactions.
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 refractory-metal composite barrier effectively blocks oxygen transport, enhancing the cleanliness of steel products and maintaining the structural integrity of the lining, contrary to conventional wisdom by promoting molten metal penetration into the refractory layer.
Implementation Method 1
infiltration of molten metal into the etched and/or porous refractory lining
Implementation Method 2
atmospheric oxygen (O2) tends to transport through melt-contacting refractory linings in metallurgical vessels
Implementation Method 3
porosity and permeability of melt-contacting refractory linings to atmospheric oxygen (O2)
Implementation Method 4
The iron in molten steel will react with oxygen species and produce iron oxides
Implementation Method 5
an in situ chemical etching-like effect in the refractory lining
Data Source
AI summary
A refractory composition for forming a working lining in a metallurgical vessel contains a coarse-grain refractory particle fraction and a fine-grain refractory particle fraction, or at least 0.25% additive calcium oxide, or at least 0.25% titanium dioxide. The coarse-grain refractory particles can include alumina particles, magnesia particles, magnesium aluminate spinel particles, zirconia particles, or doloma particles, or a combination of any of these particles. The fine-grain refractory particles can be comprised of any low-magnesia refractory oxide. The refractory composition can be applied to a metallurgical vessel by spraying, gunning, shotcreting, vibrating, casting, troweling, or positioning preformed refractory shapes, or a combination of any of these techniques. When contacted by molten metal, the molten metal penetrates into the refractory material, wetting the coarse-grain refractory particles, and forming a refractory-metal composite barrier layer that decreases or blocks oxygen transport through the refractory lining.