Monolithic Refractory Bonding with Strontium Aluminate
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Solution Overview
Problem
Monolithic refractories face challenges in developing strength quickly and maintaining corrosion resistance without using aluminous cement or with minimal CaO content, as existing solutions either require fine magnesia which can be inactive or result in slow strength development and thermal spalling issues.
Innovation Solution
A monolithic refractory composition using CaX Sr1-X Al2 O4 as a bonding material in combination with a polyvalent metal salt of oxycarboxylic acid, with specific ratios of these components and other refractory materials to enhance strength development and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminous cement is used as bonding material, then strength is improved, but corrosion resistance deteriorates due to formation of low-melting products
Solution Approach 1:
The patent removes aluminous cement (the harmful element) from the bonding material composition and replaces it with a mixture of calcined alumina and strontium carbonate, which provides similar bonding functionality without generating low-melting products that compromise corrosion resistance
Solution Approach 2:
The patent creates a composite bonding system using calcined alumina and strontium carbonate together, where the strontium carbonate reacts with water to form strontium hydroxide which then reacts with calcined alumina to form a bonding gel, achieving both strength and corrosion resistance
2Object-affected harmful factors
If magnesia is used as bonding material with polyvalent metal salt, then corrosion resistance is improved, but strength development becomes slow and thermal spalling resistance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by replacing magnesia with strontium carbonate and adjusting the grain size distribution of calcined alumina (0.1mm or smaller), which accelerates the reaction rate and strength development while maintaining corrosion resistance
Solution Approach 2:
The patent uses fine-grained calcined alumina (0.1mm or smaller) as the primary bonding material to create a locally optimized structure that reacts quickly with strontium hydroxide to form strong bonds, while the overall composition maintains corrosion resistance
3Object-affected harmful factors
If CaO content is reduced to improve corrosion resistance, then corrosion resistance is improved, but strength development becomes slow
Solution Approach 1:
The patent introduces strontium hydroxide as an intermediary substance that reacts with calcined alumina to form a bonding gel, replacing the role of CaO in aluminous cement while avoiding the formation of low-melting products, thus maintaining both strength development and corrosion resistance
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 enables faster hardening and higher strength development in monolithic refractories, reducing long-term changes and improving thermal spalling resistance, while minimizing the use of aluminous cement and CaO content.
Implementation Method 1
formation of a hydrate is slow as compared to the monolithic refractory using aluminous cement of the related art
Implementation Method 2
it is possible to obtain a monolithic refractory in which hardening is faster and the strength is higher
Implementation Method 3
a monolithic refractory hardened by reaction of magnesia to polyvalent metal salt of oxycarboxylic acid
Data Source
AI summary
In a monolithic refractory, in terms of a proportion in 100 mass% of a refractory raw material having a grain size of 8 mm or smaller, an amount of CaXSr1-XAl2O4 (where, 0≤X≤0.5) is 0.5 mass% or more and 10 mass% or less, and a polyvalent metal salt of oxycarboxylic acid is 0.05 mass% or more and 1.0 mass% or less.