Stepped Ladle Bottom Lining Slag Capture
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Solution Overview
Problem
The contamination of molten steel with slag during the casting process in steel ladles leads to reduced yield and lower quality steel due to slag entrainment, necessitating early termination of casting to avoid contamination, resulting in residual metal left in the ladle.
Innovation Solution
A refractory bottom lining with a stepped surface design that captures slag on successive sections as molten metal drains, reducing entrainment and allowing more slag-free metal to be extracted, and facilitating a counter-clockwise flow to minimize vortex formation and slag entrainment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If casting is terminated before the liquid metal level reaches the critical level to avoid slag entrainment, then slag contamination is prevented, but production yield decreases due to residual metal remaining in the ladle
Solution Approach 1:
The ladle bottom is segmented into multiple stepped sections (first section, second section, third section) with progressively lower elevations. This segmentation allows the bottom surface to interact with the liquid metal at different levels during draining, enabling slag capture at higher sections while maintaining clean flow paths at lower sections, thus allowing casting to continue to lower levels without slag contamination.
Solution Approach 2:
The invention transitions from a conventional flat bottom surface to a three-dimensional stepped structure with varying elevations. This dimensional change creates multiple interaction zones between the bottom lining and the liquid metal-slag interface, allowing slag to be captured on upper stepped sections while the lower sections maintain open flow paths, effectively separating slag removal from the main drainage path.
2Productivity
If the liquid metal level is allowed to drop to a low level to increase yield, then production efficiency improves, but slag entrainment increases due to vortexing and direct slag pulling
Solution Approach 1:
The stepped sections of the bottom lining act as intermediary structures between the liquid metal flow and the ladle bottom. These intermediaries provide surfaces for slag adhesion and create flow guidance that prevents direct contact between the draining metal stream and floating slag, reducing entrainment even at low metal levels.
Solution Approach 2:
Different sections of the bottom lining have different elevations and functions. The upper stepped sections are designed for slag capture and flow guidance, while the lower sections maintain open drainage paths. This local differentiation allows the system to handle both slag separation and efficient drainage simultaneously at different locations.
3Device complexity
If a conventional flat bottom lining is used, then the structure is simple, but slag cannot be effectively captured and vortexing occurs at low metal levels
Solution Approach 1:
The bottom lining is divided into multiple discrete stepped sections rather than using a continuous flat surface. This segmentation creates distinct functional zones for slag capture and clean flow, improving slag separation effectiveness while maintaining a relatively simple overall structure that can be constructed from standard refractory components.
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
The stepped refractory bottom lining increases the yield of slag-free steel by retaining slag on its surface and reducing residual metal in the ladle, while counter-clockwise flow helps in minimizing vortex formation and slag entrainment, thus enhancing the efficiency of the steel-making process.
Implementation Method 1
Vortexing may occur once the level of the liquid metal in the ladle drops to a critical level. The stepped refractory bottom lining facilitates a counter-clockwise flow to minimize vortex formation
Implementation Method 2
The stepped refractory bottom lining increases the yield of slag-free steel by retaining slag on its surface
Data Source
AI summary
A refractory bottom for a metallurgical vessel comprised of a bottom lining having a bottom surface that is dimensioned to overlay a bottom of a metallurgical vessel and an upper surface. The upper surface is comprised of a plurality of discrete sections that include an uppermost section, an intermediate section and a lowermost section. Each section has an upper surface at a discrete elevation such that the upper surface of the uppermost section has a highest elevation and the upper surface of the lowermost section has a lowest elevation. The upper surface of the uppermost section, the intermediate section and the lowermost section comprise a series of successive stepped sections that define a stepped path from the uppermost section downward to the lowermost section. Each successive section of the upper surface is lower than a preceding section.