Refractory Brick Slag Infiltration Resistance via Spinel Layer
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Solution Overview
Problem
Current refractory bricks used in ladles for steel making, such as high-alumina and alumina-spinel bricks, lack durability and are prone to slag infiltration and corrosion, while alumina-magnesia castable materials require specialized equipment for casting and drying, making them costly and inefficient to implement.
Innovation Solution
A refractory brick composed of alumina and magnesia raw materials with 90% or more of fine powder, silica sand, and other additives, press-molded and heat-treated to achieve a spinel-containing layer for enhanced slag infiltration resistance and corrosion resistance, eliminating the need for special construction or drying equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alumina-magnesia castable materials are used, then slag infiltration resistance and corrosion resistance are improved, but special equipment for casting and drying is required
Solution Approach 1:
The invention extracts the essential beneficial properties of alumina-magnesia castable materials (slag infiltration resistance and corrosion resistance) and transfers them to a brick format that can be manufactured using conventional equipment. The spinel-containing layer is formed during brick manufacturing rather than during in-situ casting, eliminating the need for special casting and drying equipment while retaining the protective properties.
Solution Approach 2:
The invention changes the manufacturing parameters from castable material processing to conventional brick manufacturing. By controlling the formation of spinel crystals during brick firing (rather than during casting), the material achieves the desired slag resistance properties through parameter optimization in a conventional manufacturing process.
2Reliability
If alumina-magnesia castable materials are used, then corrosion resistance is improved, but construction on spot becomes uneasy
Solution Approach 1:
The spinel-containing layer is formed in advance during brick manufacturing rather than during construction. The bricks are pre-fired to develop the protective spinel layer, so that when installed, they immediately provide corrosion resistance without requiring complex on-site casting and drying operations.
3Ease of manufacture
If high-alumina bricks are used, then ease of manufacture is improved, but durability deteriorates
Solution Approach 1:
The invention creates a composite brick structure with an alumina-magnesia composition that forms a spinel-containing layer. This composite material combines the ease of conventional brick manufacturing with the enhanced durability of alumina-magnesia materials, achieving both goals simultaneously.
4Duration of action of stationary object
If alumina-spinel bricks are used, then durability is improved, but slag infiltration increases
Solution Approach 1:
The invention creates a localized spinel-containing layer at the surface of the brick that specifically addresses slag infiltration. The spinel layer is concentrated where it is most needed (at the working surface exposed to slag), while the bulk material maintains its structural integrity and durability properties.
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 brick achieves excellent slag infiltration resistance and corrosion resistance, with a life span 1.5 to 2 times longer than conventional materials, and can be mass-produced through press molding without the need for specialized equipment, ensuring stable performance and reduced costs.
Implementation Method 1
alumina and magnesia are composed of a corundum crystal and a periclase crystal, respectively, and these react with each other at a high temperature during the use of a kiln such as ladles, thereby forming a spinel crystal while being accompanied with volume expansion
Implementation Method 2
these react with each other at a high temperature during the use of a kiln such as ladles, thereby forming a spinel crystal while being accompanied with volume expansion
Implementation Method 3
press-molded and heat-treated to achieve a spinel-containing layer for enhanced slag infiltration resistance and corrosion resistance
Data Source
AI summary
A refractory brick having durability equal to alumina-magnesia castable materials, which is especially suitable for a ladle for steel making is provided. A refractory brick prepared by using an alumina raw material and a magnesia raw material containing 90% by mass or more of a fine powder of not more than 0.5 mm, press molding and then heat treating at 100° C. or higher and not higher than 1,150° C., the refractory brick containing Al2O3 and MgO in a total sum of 90% by mass or more, from 4 to 16% by mass of MgO, from 0.5 to 5% by mass of SiO2, and Na2O and K2O in a total sum of from 0.3 to 2% by mass, with the remainder being inevitable impurities and Al2O3.