Fired Pellet Composition to Prevent Clustering in Solid Reduction
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Solution Overview
Problem
Conventional methods for preventing clustering in solid reduction furnaces are inadequate, requiring costly covering steps and additional facilities, and fail to effectively reduce slag fusion and contact between metallic irons.
Innovation Solution
Fired pellets with a specific ratio of high-viscosity slag components (Al2O3+MgO+SiO2) to total Fe and a porosity of 20% or more, produced using iron-containing raw materials with controlled LOI, to prevent slag fusion and clustering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional covering methods (Ca(OH)2, Mg(OH)2, powdery solid fuel, iron ore mixed with cement) are used to prevent clustering, then contact between metallic irons is reduced, but manufacturing cost increases and additional facilities are required
Solution Approach 1:
The invention uses the pellet's own surface characteristics (basicity and viscosity) to prevent clustering, eliminating the need for external covering materials. The pellet surface itself provides the anti-clustering function through controlled high-temperature behavior, making the system self-sufficient without additional facilities or materials.
Solution Approach 2:
The invention changes the chemical composition parameters of the pellet (specifically CaO/SiO2 ratio and Al2O3 content) to achieve desired high-temperature surface properties. By adjusting these compositional parameters, the pellet develops appropriate viscosity and basicity at high temperature, naturally preventing clustering without external covering agents.
2Reliability
If conventional covering methods are used to prevent clustering, then contact between metallic irons is reduced, but process complexity increases due to additional covering steps
Solution Approach 1:
The invention merges the pellet formation process with the anti-clustering property development. The compositional parameters for preventing clustering are integrated into the raw material formulation and pelletizing process itself, combining multiple functions into a single process flow without separate covering steps.
Solution Approach 2:
The pellet automatically develops its anti-clustering properties through its own chemical composition during the standard firing process, without requiring separate covering facilities or additional process equipment. The pellet serves its own protection function.
3Productivity
If low-melting-temperature slags are present during reduction, then reduction reaction proceeds, but slag fusion and contact cause clustering in high-temperature zones
Solution Approach 1:
The invention changes the slag composition parameters by controlling CaO/SiO2 ratio and Al2O3 content to achieve high viscosity and high basicity at operating temperatures. This parameter optimization allows the slag to remain non-fusible and high-viscosity, preventing clustering while still enabling reduction reactions to proceed.
Solution Approach 2:
The invention creates a composite slag system with specific combinations of CaO, SiO2, and Al2O3 that exhibits high viscosity and high basicity characteristics. This composite composition prevents fusion and clustering while maintaining the chemical reactivity needed for reduction processes.
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 effectively reduces slag fusion and clustering in solid reduction furnaces, enhancing operational efficiency by minimizing contact points and maintaining pellet integrity.
Implementation Method 1
a ratio of high-viscosity slag components (Al2O3+MgO+SiO2) to total Fe (T.Fe) satisfies the following Expression (1)
Implementation Method 2
The porosity is 20% or more
Implementation Method 3
an average LOI (Loss on Ignition) of 5% or more
Data Source
AI summary
Fired pellets for use in a solid reduction furnace that are effective in preventing clustering by reducing the possibility of contact between low-melting-temperature slags and thus preventing the fusion therebetween, and a method for producing such fired pellets. Fired pellets for reduction, wherein the proportion of high-viscosity slag components (Al2O3+MgO+SiO2) to the total Fe (T.Fe) satisfies an expression: (Al2O3+MgO+SiO2)/T.Fe≥0.09, and a method for producing the same. In the expression, Al2O3 represents the concentration (mass %) of Al2O3 in the fired pellets, MgO represents the concentration (mass %) of MgO in the fired pellets, SiO2 represents the concentration (mass %) of SiO2 in the fired pellets, and T.Fe represents the concentration (mass %) of T.Fe in the fired pellets.