Continuous Calcium Aluminate Melting Process
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Solution Overview
Problem
Current processes for producing calcium aluminates are restrictive in terms of particle size, requiring fine grinding and the use of bauxite blocks, which are less available and have low production yield, and involve discontinuous operation modes in melting furnaces.
Innovation Solution
A continuous process that uses fine particles of raw materials with a median diameter d50 less than or equal to 6,000 µm, eliminating the need for bauxite blocks and allowing for the valorization of fine particles, with continuous introduction and recovery of liquid calcium aluminates, reducing particle size constraints and operating mode changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fine grinding of raw materials is performed to enable sintering process, then calcium aluminates can be produced with desired mineralogical phases, but production cost increases and particle size constraints become restrictive
Solution Approach 1:
The invention changes the temperature parameter from sintering range (1400-1600°C) to melting range (≥1430°C), which fundamentally alters the reaction mechanism from solid-state sintering to liquid-phase fusion. This parameter change eliminates the need for fine particle sizes since the liquid phase facilitates complete reaction regardless of initial particle dimensions.
Solution Approach 2:
The invention utilizes phase transition by maintaining temperatures at or above the melting point of calcium aluminates, creating a liquid phase during processing. This liquid-phase fusion allows raw materials to react completely without requiring fine grinding, as the liquid medium enables intimate mixing and reaction at larger particle sizes.
2Productivity
If bauxite blocks are used in melting furnaces, then calcium aluminates can be produced by fusion process, but availability decreases and production yield becomes low
Solution Approach 1:
The invention changes the particle size parameter acceptance range by adopting liquid-phase fusion at ≥1430°C, which allows processing of fine particles (≤6mm) that were previously unusable. This parameter change expands raw material flexibility from block-only to include fines, significantly increasing available feedstock and production yield.
3Reliability
If discontinuous operation modes are used in melting furnaces, then melting process can be controlled, but operational complexity increases and productivity decreases
Solution Approach 1:
The invention implements continuous operation by maintaining the furnace in a steady-state melting mode without periodic charging and discharging cycles. Raw materials are continuously fed and molten calcium aluminates are continuously withdrawn, eliminating operational interruptions while maintaining process control through stable temperature and composition parameters.
4Manufacturing precision
If very fine particle sizes are required for sintering process, then complete reaction can be achieved, but grinding cost increases significantly
Solution Approach 1:
The invention changes the processing temperature to melting range (≥1430°C), which fundamentally alters the reaction mechanism to liquid-phase fusion. This parameter change eliminates the need for fine particle sizes since the liquid phase enables complete reaction at much larger particle dimensions, thereby eliminating expensive fine grinding operations.
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
This process reduces the cost and complexity of producing calcium aluminates by using readily available fine particles, ensuring complete fusion without unmelted particles and stabilizing the quality of the final product, while allowing control over mineralogical phases and reactivity.
Implementation Method 1
a) to melt said fine particles of raw material
Implementation Method 2
we introduce, in a continuous manner, into said tank of oven, in the form of fine particles
Implementation Method 3
They are then generally heated to a temperature between 1400 and 1600 degrees Celsius (°C) for a period of approximately 30 minutes
Data Source
Figure 1~5
Figure 2~4
AI summary
The invention relates to a process for manufacturing calcium aluminates in an industrial furnace (1), according to which fine particles of a raw material that is a source of alumina (Al2O3) and/or of aluminium (Al) and of a raw material that is a source of calcium oxide (CaO) and/or of calcium (Ca) having a median diameter d50 less than or equal to 6000 µm are introduced, continuously, into a tank (15) made of refractory material containing a permanently heated molten bath (11) in order to melt said fine particles of raw material, and a liquid mass of calcium aluminates (16) is recovered, continuously, at the outlet of the tank.