Cokeless Sinter Blend Using DRI Reverts
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Solution Overview
Problem
The iron and steel industry faces challenges with conventional sinter blend compositions due to the increasing cost and scarcity of coke breeze, as well as the difficulties in transporting and storing Direct Reduced Iron (DRI) due to its porous nature and reactivity, leading to environmental and economic issues.
Innovation Solution
Development of cokeless sinter blend compositions that utilize DRI fines and dust as a replacement energy source, combined with other iron-making reverts and additives, to produce sinters with sufficient ISO tumble strength without the need for coke breeze, thereby enhancing transportation safety and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If coke breeze is used as energy source in conventional sinter blend compositions, then sufficient energy for sintering is provided, but production costs increase and procurement becomes difficult
Solution Approach 1:
The patent replaces expensive coke breeze with cheaper DRI fines and dust that can be disposed of or repurposed. These materials are by-products of DRI production that would otherwise be waste, making them economically advantageous substitutes for coke breeze in sinter blend compositions
Solution Approach 2:
The patent recovers value from DRI fines and dust that are normally discarded as waste products. By incorporating these materials into sinter blend compositions, the process transforms waste streams into useful fuel sources, eliminating disposal costs and reducing raw material expenses
2Adaptability or versatility
If DRI is transported and stored, then it becomes available as raw material, but its porous nature and reactivity cause oxidation, moisture absorption, and safety risks
Solution Approach 1:
The patent converts the harmful reactive properties of DRI fines and dust into a beneficial fuel source. The high metallic iron content that makes DRI susceptible to oxidation is the same property that provides high energy content when combusted in the sintering process, transforming a safety hazard into a valuable energy resource
Solution Approach 2:
The patent changes the physical and chemical parameters of DRI materials by processing them through sintering. The sintering process transforms loose, reactive DRI fines into a stable, sintered product with improved handling characteristics and reduced reactivity, while maintaining the energy benefits
3Ease of repair
If iron making reverts with high total and metallic iron levels are used, then waste repurposing is improved, but excessive energy content may cause excessive temperatures and slagging
Solution Approach 1:
The patent adjusts the composition parameters of the sinter blend by combining DRI fines and dust with other materials having complementary properties. This balancing act modifies the overall energy content and chemical composition to achieve optimal sintering temperatures without excessive heat or slagging
Solution Approach 2:
The patent creates a composite sinter blend composition combining DRI fines and dust with other iron making reverts, fluxes, and binding agents. This composite approach allows the high energy content of DRI materials to be balanced with materials that moderate temperature and control slag formation, enabling successful waste repurposing
4Strength
If sinter blend composition produces high ISO tumble strength sinter, then blast furnace feedstock quality is improved, but blend formulation becomes more complex
Solution Approach 1:
The patent optimizes the sinter blend composition parameters including particle size distribution, moisture content, and chemical composition to achieve the required ISO tumble strength. By carefully controlling these parameters, the process produces high-quality blast furnace feedstock while managing formulation complexity through systematic composition design
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 cokeless sinter blend compositions achieve ISO tumble strengths of at least 72, making them suitable for blast furnace iron-making processes, while reducing transportation risks and costs by using inert DRI reverts as a fuel source, thus addressing the environmental and economic challenges associated with DRI handling.
Implementation Method 1
The sinter blend composition is then heated at high temperatures until it is sintered into a porous irregular shaped iron oxide
Implementation Method 2
The carbon of the reducing agent and the oxygen of the iron oxide material react chemically in the reducing zone of the furnace, thereby partially reducing the iron oxide to form metallic iron
Implementation Method 3
The carbon of the reducing agent and the oxygen of the iron oxide material react chemically
Implementation Method 4
DRI reverts, having high total and metallic iron levels that re-oxidize so as to become a replacement fuel source
Data Source
AI summary
Examples herein generally relate to sinter blend compositions for use in a sintering process that do not contain coke breeze (0.0% coke breeze), or contain only very small amounts of coke breeze. In particular, these sinter blend compositions are capable of repurposing mixture of iron-making reverts, having high total and metallic iron levels that re-oxidize so as to become a replacement fuel source for the coke breeze typically used in sinter blend compositions for use in a sintering process, while still managing to produce a sinter with sufficient ISO tumble strengths.