Converter Slag LIBS Analysis for Fast Basicity Measurement
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Solution Overview
Problem
Existing methods for analyzing slag components during molten iron refining, such as X-ray fluorescence and laser-based immersion techniques, face challenges with accuracy and operational difficulty due to time constraints and slag thickness variations, making it difficult to control probe height and requiring excessive time and cost.
Innovation Solution
A non-contact, remote analysis method using laser-induced breakdown spectroscopy (LIBS) is employed to irradiate slag from the side of a tilted converter-type refining furnace, allowing for rapid and accurate determination of slag components and basicity by analyzing plasma excitation light from multiple laser pulses, utilizing machine learning to create regression models for precise component and basicity estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If X-ray fluorescence analysis is used for slag composition analysis, then quantitative analysis can be performed, but the measurement surface needs to be smoothed which requires excessive time and cost
Solution Approach 1:
The patent replaces mechanical sample preparation methods (grinding, smoothing, vitrification) with a non-contact optical analysis method. The laser-induced breakdown spectroscopy (LIBS) technique uses laser pulses to ablate and ionize slag particles in the air stream, creating plasma that emits characteristic spectra for quantitative analysis without any mechanical contact or surface preparation
Solution Approach 2:
The patent introduces an intermediary sampling system that collects slag particles and transports them through a controlled air stream to the analysis zone. This intermediary system allows the slag to be analyzed in a suspended state rather than requiring solid surface preparation, enabling rapid analysis while maintaining quantitative accuracy through proper particle concentration and plasma condition control
2Temperature
If laser-based immersion probe is used for slag analysis, then analysis can be performed in molten state, but controlling probe height is operationally difficult due to slag thickness variations
Solution Approach 1:
The patent extracts the analysis function from a physical immersion probe and relocates it to a remote optical detection system. Slag particles are sampled from the molten slag surface and transported through air to a fixed analysis position where laser excitation and spectral detection occur. This separates the high-temperature sampling environment from the controlled analysis environment, eliminating probe height control issues while maintaining molten slag analysis capability
Solution Approach 2:
The patent creates a copy of the slag composition information by analyzing suspended particles that represent the molten slag composition. Instead of directly measuring the molten slag with an immersion probe, the system samples representative particles, transports them to a controlled analysis zone, and uses laser-induced plasma to generate spectral copies of the elemental composition for quantitative analysis
3Shape
If rapid cooling of slag is performed to collect analysis sample, then smooth surface can be obtained, but the analysis sample is susceptible to segregation which affects accuracy
Solution Approach 1:
The patent replaces mechanical cooling and solidification processes with direct laser-induced plasma excitation of suspended slag particles. The particles are vaporized and ionized by high-energy laser pulses before they can segregate or form non-representative microstructures. This substitution of mechanical processing with optical excitation preserves the original molten slag composition information while enabling rapid analysis without surface preparation or cooling-induced segregation
Solution Approach 2:
The patent skips the intermediate cooling and solidification steps that cause segregation by rapidly transitioning from molten slag sampling to laser-induced plasma analysis. The suspended particles are excited and analyzed in near-real-time while still representing the high-temperature liquid composition, bypassing the segregation-prone cooling phase entirely and achieving both speed and accuracy
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
Enables quick and accurate analysis of slag components and basicity during intermediate deslagging, reducing operational costs and improving refining efficiency by optimizing slag-forming agent usage.
Implementation Method 1
irradiating a surface of slag to be analyzed with a pulse laser a plurality of times to turn part of the slag into plasma
Implementation Method 2
turn part of the slag into plasma
Implementation Method 3
dispersing excitation light obtained from the slag turned into plasma and acquiring an emission spectrum of an element contained in the slag
Implementation Method 4
dispersing excitation light obtained from the slag turned into plasma and acquiring an emission spectrum
Data Source
Figure 1A~1B
Figure 2B~2A
Figure 3A~3B
AI summary
Provided is a slag component analysis method capable of quickly and accurately measuring slag components generated during refining of molten iron. The method comprises: irradiating a surface of slag to be analyzed with a pulse laser a plurality of times to turn part of the slag into plasma; dispersing excitation light obtained from the slag turned into plasma and acquiring an emission spectrum of an element contained in the slag per one pulse laser irradiation or per a plurality of pulse laser irradiations; and deriving a target component concentration or component amount ratio from the acquired emission spectrum, wherein the slag to be analyzed is slag generated in a converter-type refining furnace, and in the process of turning part of the slag into plasma, the pulse laser is applied from a side of the converter-type refining furnace tilted to remove the slag generated in the converter-type refining furnace.