Magnesia Refractory Batch with Iron Powder for Molten Layer Formation
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Solution Overview
Problem
Existing refractory ceramic batches for metallurgical melting vessels face challenges in replicating the properties of natural magnesia-rich materials, particularly in forming a molten layer at low temperatures and a dense sintered layer at high temperatures, while also having limited storage life and contamination issues in production processes.
Innovation Solution
A refractory ceramic batch comprising 66-94% magnesia-based raw materials low in iron, 5-30% calcium carbonate-based raw materials, and 1-6% iron powder, which reacts to form dicalcium ferrite at temperatures from 1000-1200°C, creating a protective molten layer and a densely sintered refractory ceramic monolithic body at higher temperatures, with stable phases ensuring good storage life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synthetic magnesia rich in iron and chalk is produced using a rotary furnace, then the desired refractory properties are achieved, but the furnace becomes contaminated and cannot be used for other purposes
Solution Approach 1:
The invention extracts the iron component from the natural magnesia source and replaces it with iron powder added to a magnesia low in iron batch. This separation allows the rotary furnace to be used for producing both synthetic magnesia rich in iron and the new batch composition without contamination, as the iron is introduced separately during batch preparation rather than during the firing process
Solution Approach 2:
The invention creates a synthetic batch composition that copies the functional properties of natural magnesia rich in iron and chalk by using magnesia low in iron combined with added iron powder and calcium carbonate. This copied composition achieves the same dicalcium ferrite formation and protective melt layer creation without requiring contaminated furnaces
2Reliability
If burnt dolomite is used in the batch, then calcium oxide is provided for dicalcium ferrite formation, but the batch has limited storage life due to hydration tendency
Solution Approach 1:
Instead of using pre-burnt dolomite which has already reacted and is prone to hydration, the invention uses calcium carbonate as a preliminary form that will decompose to calcium oxide during the controlled firing process. This preliminary action approach allows the calcium oxide to be generated in-situ at the appropriate time, avoiding the storage stability problems of burnt dolomite
Solution Approach 2:
The invention changes the chemical form of calcium from pre-converted calcium oxide (in burnt dolomite) to calcium carbonate, which is more stable during storage. The parameter change occurs during firing when calcium carbonate decomposes to calcium oxide, providing the necessary component for dicalcium ferrite formation only when needed
3Adaptability or versatility
If magnesia low in iron is used in the batch, then furnace contamination is avoided, but the batch fails to form a molten layer at low temperatures
Solution Approach 1:
The invention creates a composite batch composition combining magnesia low in iron with iron powder and calcium carbonate. This composite material achieves the low-temperature melt formation capability through the iron-calcium-carbonate reaction system while maintaining the furnace usability benefit of using low-iron magnesia as the base material
4Reliability
If iron oxide carriers are used in the batch, then iron is provided for dicalcium ferrite formation, but the batch does not form a dense sintered layer at high temperatures
Solution Approach 1:
The invention changes the physical form of iron from coarse iron oxide carriers to fine iron powder with optimized particle size distribution. This parameter change in iron morphology, combined with the calcium carbonate component, enables both complete dicalcium ferrite formation and dense sintering at high temperatures, achieving properties that iron oxide carriers alone could not provide
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 batch produces an unformed refractory ceramic product with properties similar to natural magnesia-rich materials, forming a protective molten layer at low temperatures and a dense sintered layer at high temperatures, while maintaining stability and extended storage life, suitable for lining metallurgical melting vessels.
Implementation Method 1
iron powder with a fraction in the region of 1 to 6% by mass, which reacts to form dicalcium ferrite at temperatures from 1000-1200°C, creating a protective molten layer
Implementation Method 2
forming a protective molten layer at low temperatures
Implementation Method 3
forms a densely sintered refractory ceramic monolithic body at higher temperatures
Data Source
AI summary
The invention relates to a refractory ceramic batch for the production of an unformed refractory ceramic batch, the use of a batch of this kind for lining metallurgical melting vessels and also a metallurgical melting vessel which is lined with an unformed refractory ceramic product based on a batch of this kind.