Stir-Generated Vortex Ironmaking for Reducing Agent Utilization
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Solution Overview
Problem
The existing blast-furnace ironmaking process has a low utilization rate of reducing agents, leading to increased production costs and environmental concerns due to unreacted dust in flue gases, necessitating a more efficient method to enhance agent utilization and reduce reaction cycles.
Innovation Solution
The method involves using an induction furnace with a graphite stirring paddle to create a stir-generated vortex, where iron-containing minerals, reducing agents, and slag-forming agents are sprayed into the center of the vortex for immediate mixing and reaction, achieving high reduction rates and efficient slag formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If traditional blast-furnace ironmaking uses pulverized coal as reducing agent, then the process can proceed, but the reducing agent utilization rate is low due to floating on surface and poor reaction
Solution Approach 1:
The patent introduces dynamic stirring action using a KR stirring paddle to continuously mix the molten iron surface, transforming the static floating state of pulverized coal into dynamic mixing. This ensures the reducing agent is uniformly distributed and fully contacted with iron oxides, resolving the contradiction between low utilization rate and long reaction cycle.
Solution Approach 2:
The patent uses molten iron as an intermediary medium. The pulverized coal is first mixed with molten iron through stirring, forming a unified reacting mass. This intermediary state ensures complete contact between reducing agent and iron oxides, eliminating the floating problem and improving both utilization rate and reaction efficiency.
2Productivity
If anthracite dust is sprayed and blown from tuyere into blast furnace, then reduction process can occur, but unreacted dust remains in flue gas causing environmental pollution
Solution Approach 1:
The patent employs self-service by using the molten iron itself as the mixing medium. The KR stirring paddle stirs the molten iron to automatically distribute and react the pulverized coal, eliminating the need for external spraying systems. This self-mixing mechanism ensures complete reaction and prevents unreacted dust from entering flue gas.
Solution Approach 2:
The patent replaces the mechanical spraying and blowing system with a thermal-chemical mixing system. Instead of forcing pulverized coal into the blast furnace through mechanical means, the system uses molten iron's thermal energy and stirring action to achieve mixing and reaction, eliminating mechanical dust injection and associated pollution.
3Productivity
If blast-furnace operating indicators are optimized locally, then some improvements can be achieved, but pig iron cost reduction is limited and profit margin is small
Solution Approach 1:
The patent fundamentally changes the operational parameters by introducing controlled stirring action and using molten iron as the reaction medium. This transforms the traditional batch process into a continuous mixing-reaction process, achieving superior reducing agent utilization and shorter reaction cycles that significantly reduce production costs beyond local optimizations.
Solution Approach 2:
The patent creates a composite reacting system combining molten iron, pulverized coal, and iron oxides in a unified mixture. This composite approach ensures complete interaction between all components, maximizing reaction efficiency and reducing agent utilization, thereby achieving substantial cost reductions compared to separate traditional 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
This approach significantly increases the reducing agent utilization rate, shortens the ironmaking cycle, reduces waste, and improves environmental conditions by achieving high reduction rates and low iron content in slags, while being energy-efficient and cost-effective.
Implementation Method 1
heating the pig iron to a molten state to form a molten iron
Implementation Method 2
Placing a pig iron in an induction furnace, heating the pig iron to a molten state
Implementation Method 3
stirring the molten iron to form a vortex
Implementation Method 4
Through the rotary stirring of a stirrer
Implementation Method 5
iron in ore for ironmaking is reduced from oxides to molten pig iron at high temperatures by using coke as fuel and reducing agents
Implementation Method 6
method for ironmaking by smelting reduction
Implementation Method 7
the reducing agent and the slag-forming agent are immediately drawn into a smelting pool to be mixed thoroughly and react
Data Source
AI summary
A method for ironmaking by smelting reduction in a stir-generated vortex includes: (1) placing a pig iron in an induction furnace, and then heating the pig iron to a molten state to form a molten iron, and maintaining the molten iron to be greater than or equal to 1450° C.; (2) stirring a center of the molten iron to form a vortex with a height-to-diameter ratio of 0.5-2.5, and continuously performing stirring; (3) mixing and grinding on an iron-containing mineral, a reducing agent and a slag-forming agent in a mass ratio of 1:(0.1-0.15):(0.25-0.4) to obtain a powder mixture, spraying and blowing the powder mixture to a center of the vortex, performing a reduction reaction, and stopping the stirring after the molten iron and molten slags are obtained, wherein a waste gas is produced; and (4) discharging the molten iron and the molten slags respectively, and exhausting a treated waste gas.