Electric Arc Furnace Slag Conditioning With Forming Gas Reduction
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Solution Overview
Problem
Electric arc furnace slags with high iron oxide content have limited usability and recyclability, making large-scale high-quality recycling impossible, and conventional reduction methods are inefficient and energy-intensive, with residues often remaining.
Innovation Solution
Conditioning electric arc furnace slag by treating it in a molten state with a carbon-containing reducing agent and introducing a hydrogen-containing forming gas to reduce iron oxide content, using renewable energy sources for melting and controlling the process in the electric arc furnace or ladle to achieve a desired slag composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional reduction methods with solid carbon are used on electric arc furnace slag, then iron oxide content is reduced, but additional time and energy are required and residues remain in the slag
Solution Approach 1:
The patent changes the physical state of the carbon-containing reducing agent from solid to gaseous form (using gasified carbon sources such as CO, CH4, or C2H2). This parameter change enables more efficient mass transfer and reaction kinetics, reducing both time and energy consumption while achieving complete reduction without solid residues in the slag.
Solution Approach 2:
The patent replaces the mechanical mixing and contact required by solid carbon reduction with a gaseous reduction agent that can diffuse and react uniformly throughout the molten slag. This substitution eliminates the need for mechanical agitation and ensures complete reaction without leaving solid residues.
2Adaptability or versatility
If iron oxide-rich slag is used in construction industry or landfill construction, then limited applications are achieved, but high-quality recycling on large scale is impossible
Solution Approach 1:
The patent applies chemical reduction to change the iron oxide content parameter from >10 wt% to <10 wt%, transforming the slag composition to meet construction industry specifications. This enables the slag to be used in concrete production, road construction, and other high-quality applications rather than being limited to landfill construction.
Solution Approach 2:
The patent converts the harmful high iron oxide content (which limits usability) into a benefit by reducing it to acceptable levels. The iron oxide that previously made the slag unsuitable for high-quality applications becomes a manageable parameter that can be controlled through gas-phase reduction, turning a waste product into a valuable construction material.
3Use of energy by moving object
If carbon is introduced into slag to cause foaming and induce reverse reaction, then energy consumption and noise emissions are reduced, but oxide iron content remains very high at 10 wt.% and above
Solution Approach 1:
The patent introduces a gaseous carbon-containing reducing agent as an intermediary that facilitates the reduction of iron oxide through a controlled chemical reaction. The gas phase intermediary enables uniform distribution and reaction throughout the molten slag, achieving both energy efficiency and effective iron oxide removal without the limitations of solid carbon or foaming methods.
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
Reduces iron oxide content to below 10 wt.% and enables the production of a more reactive, granulated slag suitable for cement clinker substitutes, enhancing its recyclability and opening up new applications.
Implementation Method 1
treating it in a molten state with a carbon-containing reducing agent, wherein a hydrogen-containing forming gas is introduced into the molten electric arc furnace slag
Implementation Method 2
The electric arc furnace has several electrodes that can be, or are, supplied with an electric current, thus providing the energy required for melting
Implementation Method 3
These are then melted to produce an iron melt and a layer of molten electric arc furnace slag
Data Source
Figure 1~2
AI summary
The invention relates to a method for conditioning electric arc furnace slag (1) which is treated in the molten state with a carbon-containing reducing agent, wherein a hydrogen-containing forming gas is introduced into the molten electric arc furnace slag (1).