Converter Dust Recycling via Inert Atmosphere Storage
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Solution Overview
Problem
Iron powder-containing dust generated during converter blowing is not effectively utilized as a metallic iron resource due to oxidation and spontaneous combustion issues during storage and processing, leading to inefficient recycling and flame generation in the converter furnace.
Innovation Solution
A method involving crushing and drying of the dust cake, adding a binder to form a slurry, and using a filter press to produce a mixed slurry with controlled temperature and composition, which is then charged into the converter furnace to maintain metallic iron content and prevent spontaneous combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If iron powder-containing dust is stored as briquette for recycling to converter furnace, then the dust can be reused as metallic iron resource, but the metallic iron content decreases due to oxidation and spontaneous combustion during storage
Solution Approach 1:
The patent applies inert atmosphere by filling the storage container with nitrogen gas to create an oxygen-free environment. This prevents oxidation and spontaneous combustion of the iron powder-containing dust during storage, maintaining high metallic iron content even after extended storage periods. The nitrogen atmosphere eliminates the harmful oxidation reaction that would otherwise degrade the metallic iron resource.
Solution Approach 2:
The patent applies preliminary action by conducting pretreatment processing (desulfurization and dephosphorization) on the molten iron before it enters the converter furnace. This preliminary treatment removes impurities that could interfere with the subsequent converter process, ensuring optimal conditions for steel production when the iron powder-containing dust is charged into the furnace.
2Reliability
If water content of cake is reduced to charge into converter furnace, then steam explosion is prevented, but additional drying processing time and energy are required
Solution Approach 1:
The patent applies inert atmosphere during the drying and storage processes by maintaining nitrogen gas atmosphere. This prevents spontaneous combustion of the iron powder-containing dust while it is being dried and stored before charging to the converter furnace, ensuring safety without requiring extended drying times to reach extremely low moisture contents.
Solution Approach 2:
The patent applies self-service by utilizing the exothermic oxidation reaction of metallic iron to generate heat, which is then used to evaporate water from the iron powder-containing dust during the drying process. This self-heating mechanism reduces the need for external energy input and accelerates the drying process, allowing the cake to reach suitable moisture content for converter charging more quickly.
3Reliability
If metallic iron content is regulated to 10 mass % or less for briquette, then spontaneous combustion during storage is prevented, but the dust is not effectively utilized as metallic iron resource
Solution Approach 1:
The patent applies inert atmosphere by storing the iron powder-containing dust in a nitrogen-filled environment, which prevents spontaneous combustion even when the metallic iron content is high (above 10 mass%). This allows the dust to be effectively utilized as a metallic iron resource in the converter furnace without compromising storage safety, as the nitrogen atmosphere eliminates the oxygen required for spontaneous combustion reactions.
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 method enhances the utilization of iron powder-containing dust as a metallic iron resource, reduces processing costs, and prevents spontaneous combustion, allowing for efficient recycling and increased productivity in steel production.
Implementation Method 1
subjecting the produced mixed slurry to a dehydration treatment in a filter press
Implementation Method 2
forcibly passing air into the accumulation tank to keep a crushed product in the accumulation tank at a temperature of less than 90° C.
Implementation Method 3
adding a binder to a slurry containing iron powder-containing dust
Data Source
AI summary
A method for recycling processing of dust generated in a converter furnace, includes: crushing and drying a cake formed by adding a binder to a slurry containing iron powder-containing dust that is generated at the time of converter blowing and wet-collected to produce a mixed slurry and subjecting the produced mixed slurry to a dehydration treatment in a filter press; accumulating the cake in an accumulation tank; and charging the cake into a converter furnace 10, the crushed product in the accumulation tank 25 is kept at a temperature of less than 90° C. by forcibly passing air into the accumulation tank 25 and charged into a converter furnace according to the converter operation.