Induction Melting of Direct Reduced Iron for Slag Separation
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Solution Overview
Problem
Conventional methods using carbon-based reducing materials in the reduction process for direct reduced iron are inefficient when transitioning to hydrogen-based reducing materials, leading to decreased separation efficiency of slag from metal, and gangue removal is challenging, especially when using low-grade iron ore.
Innovation Solution
A method involving induction melting furnace processes with controlled gas blowing, slag composition adjustment, and heat supply to maintain slag fluidity, allowing efficient separation of slag from metallic iron, producing high-purity solid iron and utilizing by-products for civil engineering materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrogen-based reducing materials are used instead of carbon-based reducing materials in the reduction process, then CO2 emissions are reduced, but the separation efficiency of slag from metal decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the reducing material from carbon-based to hydrogen-based, which fundamentally alters the reduction mechanism. This parameter change reduces CO2 emissions while the patent compensates for the reduced separation efficiency through process optimization in the melting and separation stage
Solution Approach 2:
The patent applies different quality requirements to different stages of the process: in the reduction stage, hydrogen-based materials are used for environmental benefits, while in the melting stage, specific temperature and compositional conditions are created to optimize slag-metal separation, addressing each stage's local requirements
2Quantity of substance
If low-grade iron ore with high gangue content is used, then raw material cost is reduced, but the difficulty of gangue removal increases
Solution Approach 1:
The patent performs preliminary classification and preparation of iron ore before the reduction process, selecting ores with suitable gangue characteristics that can be effectively removed in subsequent processing stages, thereby facilitating easier gangue removal despite using lower-grade ores
Solution Approach 2:
The patent implements a continuous process where gangue removal is integrated throughout the production sequence rather than as a separate discrete step, maintaining continuous optimization of slag composition and properties to facilitate ongoing separation efficiency
3Device complexity
If conventional melting methods are used without gas blowing, then the process is simpler, but melting time and energy consumption increase
Solution Approach 1:
The patent introduces gas blowing technology into the melting process, using pneumatic action to enhance heat transfer and agitation in the molten material. This accelerates melting and improves separation efficiency, with the added complexity being justified by the significant reductions in melting time and energy consumption
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 method reduces melting time and energy consumption by maintaining slag in a fluid state, enabling effective separation of slag and production of high-purity solid iron, while also utilizing slag as a construction material.
Implementation Method 1
melting the direct reduced iron in an induction melting furnace
Implementation Method 2
melting the direct reduced iron in an induction melting furnace to produce molten iron
Implementation Method 3
blowing gas into the molten iron for a limited time of or throughout the melting step
Data Source
AI summary
A technology for melting direct reduced iron while efficiently removing a gangue portion from the direct reduced iron, including obtaining a direct reduced iron by bringing iron ore or a mixture thereof and composition adjusting material together with a reducing material under heating; melting the direct reduced iron to obtain molten iron, and removing a slag outside the induction melting furnace; and optionally refining the molten iron. A charging temperature of melting the direct reduced iron ranges from after finishing direct reduction to atmospheric temperature; and melting includes blowing gas into the molten iron for a limited time of or throughout melting, and optionally includes one or more steps: 1) adding an adjuster for adjusting components of the slag, 2) supplying heat to the slag from a heat source disposed above the induction melting furnace, and 3) supplying one or more reducing solids and/or one or more reducing gases.