Converter Slag Flow Estimation for Lower Auxiliary Material Use
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Solution Overview
Problem
Existing methods for controlling slag basicity and reducing the consumption of auxiliary raw materials in steel refining processes are inadequate, as they fail to accurately estimate the amount and physical properties of removed slag, leading to inefficiencies and increased costs.
Innovation Solution
A method that estimates the amount and physical properties of removed slag by measuring the shape and velocity of the slag removal flow within a converter-type refining furnace, using a control system to adjust refining processes and minimize the consumption of auxiliary raw materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If desiliconization processing is performed on molten pig iron with high silicon concentration, then silicon is effectively removed, but a larger amount of SiO2 is generated requiring more CaO-containing substance and increasing production cost
Solution Approach 1:
The patent extracts and removes the SiO2-rich intermediate slag generated during desiliconization processing before proceeding to dephosphorization. By taking out this intermediate slag containing excess SiO2, the system prevents the need to add large amounts of CaO-containing substance later to maintain slag basicity, thus resolving the contradiction between silicon removal effectiveness and CaO consumption.
Solution Approach 2:
The patent discards the intermediate slag generated during desiliconization as a separate waste stream rather than mixing it with subsequent processing slag. This discarding approach eliminates the burden of managing excessive SiO2 in the dephosphorization stage, reducing the need for additional CaO-containing substances and lowering production costs.
2Loss of substance
If intermediate slag removal is performed to reduce CaO-containing substance consumption, then auxiliary raw material usage decreases, but accurate estimation of removed slag amount and properties becomes necessary
Solution Approach 1:
The patent implements a feedback mechanism where the amount and properties of removed intermediate slag are measured and used to adjust subsequent processing parameters. By measuring the actual slag removal quantity and characteristics, the system can precisely control the amount of CaO-containing substance needed in dephosphorization, achieving both material reduction and measurement accuracy.
Solution Approach 2:
The patent replaces traditional mechanical weighing methods for slag measurement with observation-based estimation techniques. By observing the slag removal flow characteristics and using empirical relationships, the system achieves accurate slag amount estimation without complex mechanical measurement devices, reducing auxiliary raw material consumption while maintaining precision.
3Productivity
If slag basicity is controlled within a predetermined range to promote dephosphorization reaction, then phosphorus removal efficiency is improved, but larger amount of slag is generated when silicon concentration is high
Solution Approach 1:
The patent segments the slag management process into distinct stages: desiliconization slag removal and dephosphorization slag management. By separating these processes and removing intermediate slag after desiliconization, the system can control slag basicity efficiently during dephosphorization without being burdened by excessive SiO2 from high-silicon pig iron, thus improving phosphorus removal efficiency while managing total slag generation.
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
Accurate estimation of slag removal allows for efficient production of molten steel with reduced consumption of auxiliary raw materials, improving process efficiency and reducing costs.
Implementation Method 1
silicon or phosphorus in molten pig iron is removed through oxidation by oxygen in an oxygen source (an oxygen gas or iron oxide) supplied to the molten pig iron
Implementation Method 2
sulfur in molten pig iron reacts with a desulfurizing material, such as CaO, and the sulfur is removed into slag
Implementation Method 3
P2O5 generated by this oxidation reaction reacts with CaO and is absorbed by slag that is formed as the CaO-containing substance turns into slag
Data Source
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AI summary
Proposed is a method for operating a converter that reduces the consumption amount of auxiliary raw material. When supplying an oxygen source to molten pig iron inside a converter-type refining furnace and performing desiliconization, dephosphorization, and decarburization refining, the method measures one or two or more selected from a slag removal flow shape, a slag removal flow velocity, and a slag surface shape while discharging slag through a throat to estimate one or both of a slag removal amount and physical properties of removed slag. When sequentially performing one refining step of performing one or both of desiliconization in part or in whole and dephosphorization, an intermediate slag removal step of discharging part or all of generated slag through the throat, and the remaining other refining step, in the intermediate slag removal step, the method measures one or two selected from the slag removal flow shape, the slag removal flow velocity, and the slag surface shape, estimates one or both of the amount and physical properties of slag removed, estimates a remaining slag amount, or the remaining slag amount and a slag composition, and based on the estimation result, determines an amount of auxiliary raw material to be fed during refining in the other refining step.