Refractory Lining Separation by Destructive Hydration Recycling
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Solution Overview
Problem
Existing methods for recycling Magnesia-Carbon bricks from metallurgical vessels are limited by contamination from various refractory compositions and metal carbides, leading to low-quality reclaimed aggregates and high costs, making them unsuitable for high-quality refractory products.
Innovation Solution
A method involving destructive hydration and selective separation of refractory components based on their hydration characteristics, using processes like hydrating, screening, and air classification to separate and recycle high-quality refractory materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common reclaiming processes are used on demolished Magnesia-Carbon linings, then the material can be processed, but the reclaimed aggregate contains high levels of contamination from various refractory compositions and metal carbides, resulting in low-quality material suitable only for limited applications
Solution Approach 1:
The invention changes the chemical state of specific contaminants by inducing controlled hydration reactions. By adjusting moisture content to 2-10% and applying thermal energy at 50-200°C, hydratable phases (calcium aluminate, calcium silicate, dolomite) transform into hydrated forms with different physical properties, enabling their separation from non-hydratable Magnesia-Carbon refractory material through magnetic and density-based separation processes
Solution Approach 2:
The invention exploits phase transitions during hydration reactions. Contaminants containing hydratable phases undergo chemical phase changes when exposed to controlled moisture and heat, transforming from anhydrous to hydrated states. This phase transition fundamentally alters the magnetic susceptibility and density of contaminant particles, allowing them to be separated from the non-hydratable Magnesia-Carbon aggregate through magnetic separation and density-based classification
2Productivity
If Magnesia-Carbon bricks are recycled through conventional methods, then some material can be recovered, but the process is limited by the fact that MgO hydrates and disintegrates over time, making the bricks difficult to recycle into high-quality applications
Solution Approach 1:
The invention converts the harmful effect of hydration (which causes disintegration and quality degradation) into a beneficial separation mechanism. By applying controlled hydration conditions, the hydratable contaminant phases selectively react and transform, while the non-hydratable Magnesia-Carbon phases remain unchanged. This differential reaction converts what was previously a degradation mechanism into a powerful separation tool that increases both yield and purity of reclaimed Magnesia-Carbon aggregate
Solution Approach 2:
The invention segments the mixed refractory material into distinct groups based on their hydration behavior. Through controlled hydration treatment, the mixture separates into: (1) hydrated contaminant phases with altered magnetic and density properties, and (2) non-hydratable Magnesia-Carbon phases that retain original properties. Multiple separation stages then further segment these groups to produce high-purity reclaimed aggregate suitable for Magnesia-Carbon brick manufacturing
3Reliability
If demolished lining is subjected to grinding and sorting processes, then some separation occurs, but contamination from Alumina-Magnesia-Carbon bricks, slag adherence, and metal carbides remains at levels that disqualify the material for high-quality refractory products
Solution Approach 1:
The invention changes the chemical and physical parameters of contaminant particles through controlled hydration. By exposing the ground material to specific moisture (2-10%) and temperature (50-200°C) conditions, hydratable phases transform into hydrated forms with fundamentally different magnetic susceptibility and density. This parameter change enables magnetic separation to remove alumina-magnesia-carbon contaminants and density-based separation to remove slag adhering to Magnesia-Carbon particles, achieving contamination levels below 1%
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
Enables the production of contamination-free, high-quality refractory aggregates suitable for new refractory products by effectively separating and recycling Magnesia-Carbon bricks, improving yield and reducing costs.
Implementation Method 1
hydrating the mixture of refractory components to destructively hydrate at least some components of the mixture of refractory components
Data Source
AI summary
A method of separating a mixture of used refractory components of different chemistry types obtained from a demolished refractory includes hydrating the mixture of refractory components to destructively hydrate at least some components of the mixture of refractory components, and separating, based on size, the at least some components from other components of the mixture of refractory components.