Converter Steelmaking Dephosphorization via Dynamic Pressure Control
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Solution Overview
Problem
The existing converter steelmaking methods face inefficiencies in dephosphorization refining due to high slag generation and thermal losses, leading to decreased productivity and increased environmental impact, particularly when using CaF2-based fluxes and inadequate blowing control.
Innovation Solution
A converter steelmaking method that simultaneously performs decarburization and dephosphorization refining by supplying gaseous oxygen and a CaO-containing powdery dephosphorizing agent to the molten iron surface, with controlled dynamic pressure to minimize slag generation and enhance dephosphorization efficiency, using a top blowing lance with specific nozzle configurations and blowing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CaF2-based flux is used as a slag-forming accelerator, then dephosphorization efficiency is improved, but environmental pollution increases and slag discharge amount increases
Solution Approach 1:
The invention extracts and removes CaF2-based flux from the dephosphorization process, replacing it with CaO-based slag-forming agents. This elimination of harmful fluorine-containing materials resolves the contradiction by maintaining dephosphorization efficiency through alternative chemical mechanisms while eliminating environmental pollution associated with CaF2 discharge
Solution Approach 2:
The invention changes the chemical composition parameters of the slag-forming agent from CaF2-based to CaO-based materials. By adjusting the chemical parameters and using alternative compounds, the process maintains its dephosphorization function while eliminating the harmful environmental effects of fluorine discharge
2Reliability
If quicklime powder is blown into the converter without adequate control, then dephosphorization refining is performed, but quicklime scatters and efficiency deteriorates
Solution Approach 1:
The invention implements feedback control by monitoring the blowing conditions and adjusting the oxygen flow rate and quicklime powder supply accordingly. This closed-loop control ensures that the dynamic pressure remains within the optimal range, preventing scattering while maintaining effective dephosphorization refining
Solution Approach 2:
The invention optimizes the dynamic pressure parameter by controlling it within a specific range (0.05-0.5 MPa). By adjusting and maintaining this critical parameter, the process achieves effective dephosphorization while preventing quicklime scattering and maintaining high refining efficiency
3Reliability
If dynamic pressure of gas jet is increased to enhance dephosphorization, then dephosphorization ability improves, but quicklime scattering increases and efficiency deteriorates
Solution Approach 1:
The invention identifies and optimizes the dynamic pressure parameter, establishing an optimal range (0.05-0.5 MPa) that balances dephosphorization ability with prevention of quicklime scattering. By controlling this parameter within the specified range, the process achieves maximum dephosphorization efficiency without the harmful effects of excessive scattering
Solution Approach 2:
The invention applies partial action by using moderate dynamic pressure within the optimal range rather than excessive pressure. This controlled approach provides sufficient dephosphorization ability while avoiding the scattering problems that would occur with excessive pressure, thereby maintaining high refining efficiency
4Reliability
If molten iron is preliminarily dephosphorized before converter charging, then phosphorus removal efficiency improves, but thermal margin decreases and productivity reduces
Solution Approach 1:
The invention merges the dephosphorization process with the converter steelmaking process by performing dephosphorization directly in the converter during the steelmaking operation. This integration eliminates the need for separate preliminary dephosphorization steps, thereby maintaining high phosphorus removal efficiency while improving productivity and thermal efficiency
Solution Approach 2:
The invention enables continuous dephosphorization action during the entire converter steelmaking process rather than requiring discrete preliminary treatment steps. This continuous process maintains effective phosphorus removal while eliminating the thermal losses and time delays associated with separate pretreatment operations
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 reduces slag generation, maintains high dephosphorization rates with lower dephosphorizing agent usage, and decreases environmental load by optimizing the dynamic pressure of the gas jet and dephosphorizing agent distribution, achieving efficient and productive steel production.
Implementation Method 1
supplying gaseous oxygen from a top blowing lance into a converter to perform decarburization refining of molten iron
Implementation Method 2
simultaneously performing decarburization and dephosphorization refining
Implementation Method 3
adding a CaO-containing powdery dephosphorizing agent to simultaneously decarburize and dephosphorize the molten iron
Implementation Method 4
the dynamic pressure when a gas jet blown from respective lance nozzles of the top blowing lace is impinging onto a bath surface of the molten iron is controlled
Data Source
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AI summary
[Problem] It is to provide a converter steelmaking method capable of efficiently performing dephosphorization refining in the production of molten steel by simultaneous decarburization refining and dephosphorization refining of molten iron in a converter, which is advantageous over the conventional method. [Solution] In a converter steel making method by supplying gaseous oxygen into a converter to perform decarburization refining of molten iron while adding a powdery CaO-containing dephosphorizing agent to form a slag of the dephosphorizing agent to perform simultaneous decarburization and dephosphorization of molten iron to thereby produce molten steel, the dephosphorizing agent is supplied to a bath surface of the molten iron together with at least one gas jet from the top blowing lance and a dynamic pressure when the gas jet from the top blowing lance is impinging onto the bath surface of the molten iron is controlled to an appropriate value in consideration of an increase due to the kinetic energy of the accompanying dephosphorizing agent.