Thermal Insulating Firebrick Pore Size Control
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Solution Overview
Problem
Existing methods for producing thermal insulating firebricks face challenges such as internal cracks due to combustion defects, difficulty in retaining fine bubbles, and the lack of inexpensive fine combustibles, limiting the production of high-porosity firebricks with excellent thermal insulation properties.
Innovation Solution
A thermal insulating firebrick is formed by molding and drying a bubble-containing slurry with a fire-resistant powder and water, achieving a porosity of 60% or more and 80% of the volume consisting of pores with a size of 200 μm or less, using materials like alumina, mullite, andalusite, and zirconia, and incorporating auxiliaries for foaming and stability, which reduces thermal conductivity and allows use in high-temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If combustibles are added to slurry to form pores by combustion, then porosity is improved, but internal cracks occur due to temperature rise from combustion
Solution Approach 1:
The invention changes the fundamental mechanism from combustion-based pore formation to gas generation through chemical reaction. Instead of using combustibles that cause temperature rise and internal cracks, the patent employs a gas generating material that reacts with water to produce gas bubbles in situ, creating pores without thermal stress and combustion-related defects
Solution Approach 2:
The invention replaces the thermal/combustion mechanism with a chemical mechanism. The gas generating material undergoes a chemical reaction with water to generate gas, substituting the combustion process that causes harmful temperature rises and internal cracks with a controlled chemical gas generation process
2Quantity of substance
If diatomaceous earth is used as main raw material for high porosity, then thermal insulation is improved, but heat resistance deteriorates above 1,000°C
Solution Approach 1:
The invention uses a composite approach by combining fire-resistant ceramic powders (alumina, mullite, andalusite, cordierite, spinel, magnesia, or zirconia) with a gas generating material. This composite system achieves both high porosity through gas-generated bubbles and high heat resistance through the use of refractory ceramic materials that can withstand temperatures exceeding 1,000°C
3Manufacturing precision
If fine combustibles are used to form fine pores, then pore size control is improved, but material cost and availability worsen
Solution Approach 1:
The invention changes from using fine combustible particles as pore-forming agents to using a gas generating material that produces gas bubbles within the slurry. This approach generates fine pores (80% or more by volume with diameter of 200 μm or less) without requiring expensive fine combustibles, as the gas bubbles are generated in situ through chemical reaction with water
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 resulting firebrick exhibits superior thermal insulation properties while maintaining fire resistance and structural integrity, even at high temperatures, with reduced thermal conductivity and increased porosity, enabling effective use in various applications.
Implementation Method 1
generating gas inside slurry mixed with a gas generating material
Implementation Method 2
incorporating auxiliaries for foaming and stability
Implementation Method 3
a thermal insulating firebrick with a porosity of 60% or more, and in which 80% or more volume with respect to a total pore volume consists of pores with a pore size of 200 μm or less
Data Source
AI summary
An object of the invention is to provide, in porous thermal insulating firebricks formed by molding and drying bubble-containing slurry obtained by foaming slurry containing a fire resistant powder and water, a thermal insulating firebrick superior in thermal insulating property in spite of the same composition and porosity.A porous thermal insulating firebrick formed by molding and drying bubble-containing slurry obtained by foaming slurry containing a fire resistant powder with a heat resistant temperature of 1,000° C. or higher and water has the porosity of 60% or more, and 80% or more volume with respect to a total pore volume of the inside of the thermal insulating firebrick consists of pores having a pore size of 200 μm or less.