Composite Iron Pellet Core-Shell Structure for Gas Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The ironmaking industry faces challenges in reducing natural gas consumption while maintaining or increasing productivity, as existing methods for producing iron with solid carbon materials have limitations in reducibility and efficiency.
Innovation Solution
A composite iron pellet with a core and shell structure is developed, comprising an inner core of iron ore and a carbonaceous reducing agent, and an outer shell of unreduced iron ore, which is fired to achieve high iron oxide content and efficient reduction in the presence of reformed natural gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If solid carbon materials are used as reducing agents to replace natural gas, then natural gas consumption is reduced, but reducibility and efficiency deteriorate
Solution Approach 1:
The pellet is divided into a core portion containing carbonaceous material and an outer shell portion containing iron ore, enabling simultaneous reduction and protection functions in different zones
Solution Approach 2:
The invention uses a composite structure combining carbonaceous material (coke, coal, or charcoal) in the core with iron ore in the shell, creating a multi-functional material that achieves both energy efficiency and high reducibility
2Strength
If the coating layer is densified to increase pellet strength, then strength is improved, but reducibility in the central part deteriorates
Solution Approach 1:
The pellet structure is segmented into a core portion with reducing agent and an outer shell portion, allowing the shell to provide strength while the core maintains reducibility through controlled porosity and material composition
Solution Approach 2:
Different regions of the pellet have different properties: the core contains carbonaceous material for reduction, while the outer shell provides structural strength and protection, with each zone optimized for its specific function
3Productivity
If carbonaceous material is added to iron ore to create two-layer structure, then reducibility is improved, but manufacturing complexity increases
Solution Approach 1:
The carbonaceous material is pre-added to the iron ore mixture before pelletizing, allowing the reducing agent to be incorporated into the pellet structure during the forming process rather than requiring subsequent coating or treatment steps
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 approach reduces natural gas consumption while maintaining or increasing productivity by enhancing the reducibility and strength of the iron pellets, allowing for effective iron production with improved physical, mechanical, and metallurgical properties.
Implementation Method 1
the inner core comprises a reducing agent comprising a carbonaceous material... reducing the composite iron pellets in the presence of reformed natural gas
Implementation Method 2
the pellet is fired... which is fired to achieve high iron oxide content and efficient reduction
Data Source
AI summary
Disclosed herein are methods and compositions for producing composite iron pellets comprising an inner core comprising iron ore and a reducing agent comprising a carbonaceous material; and an outer shell comprising unreduced iron ore. The resulting composite iron pellets can be used to produce direct reduced iron (DRI) with improved productivity while reducing gas consumption.