Stepped Ladle Bottom Lining Slag Retention
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Solution Overview
Problem
The challenge in steel production is the contamination of molten steel with slag during casting, leading to reduced yield and quality due to slag entrainment, which occurs when the liquid metal level in the ladle drops, causing vortexing and direct entrainment of slag into the steel stream.
Innovation Solution
A refractory bottom lining for metallurgical vessels with a stepped surface design that retains slag on successive sections as the metal level decreases, reducing the likelihood of slag entrainment by creating a counter-clockwise flow path to retard vortex formation and allowing more slag-free metal to be drained.
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 liquid metal remaining in the ladle
Solution Approach 1:
The bottom lining is segmented into multiple stepped sections (first section, second section, third section) at different elevations. Each section acts as an independent slag retention zone, allowing slag to be captured at multiple levels as the liquid metal drains, thereby extending the safe casting range and increasing yield without compromising steel quality.
Solution Approach 2:
The invention introduces a vertical dimensional structure with stepped sections at different elevations rather than a flat bottom surface. This vertical segmentation creates multiple horizontal retention planes that intercept slag particles at various heights, effectively increasing the slag-free casting capacity while maintaining steel purity.
2Productivity
If the liquid metal level is allowed to drop to increase yield, then more steel can be cast, but vortexing occurs causing slag entrainment and contamination
Solution Approach 1:
The stepped sections are pre-configured at specific elevations to intercept slag particles before they can be entrained into the draining steel stream. The first section at the highest elevation provides preliminary slag capture, while subsequent sections provide additional protection as the metal level drops, allowing extended casting without vortex-induced contamination.
Solution Approach 2:
The stepped bottom sections serve as intermediary structures between the liquid metal and the drain opening. These intermediate structures create a physical barrier that intercepts slag particles, preventing direct contact between the draining steel and slag at the critical low metal level, thus eliminating the harmful entrainment effect.
3Device complexity
If a flat bottom lining is used, then the structure is simple, but slag cannot be retained effectively as metal level decreases
Solution Approach 1:
The bottom lining is divided into multiple stepped sections (first section, second section, third section) with progressively lower elevations. Each segment functions as an independent slag retention zone, creating multiple interception opportunities for slag particles as the metal level drops, significantly improving slag retention capability while maintaining reasonable structural complexity.
4Volume of stationary object
If the bottom lining extends close to the side wall to maximize capacity, then ladle capacity is increased, but slag entrainment risk increases at low metal levels
Solution Approach 1:
The stepped sections are strategically positioned at different locations and elevations within the ladle bottom area. Each section provides localized slag retention functionality tailored to its position, allowing the ladle to maintain high capacity while distributing slag retention capability across multiple zones, thereby reducing overall entrainment risk even at low metal levels.
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 solution effectively increases the yield of slag-free steel by minimizing residual metal in the ladle and reducing slag entrainment, while also retarding vortex formation at the drain opening, thus improving the quality and quantity of the cast steel.
Implementation Method 1
vortexing, i.e., swirling, in the vicinity of the well block. Vortexing may occur once the level of the liquid metal in the ladle drops to a critical level
Data Source
AI summary
A refractory bottom lining for lining the bottom of a metallurgical vessel. The refractory bottom includes a stepped portion and an impact portion. The impact portion is formed of a first refractory material. The stepped portion is formed of a second refractory material and is disposed around the impact portion. The stepped portion includes an upper surface that has a plurality of discrete surface sections. The plurality of discrete surface sections includes an uppermost surface section, at least two intermediate surface sections and a lowermost surface section. Each surface section has a different elevation such that the uppermost surface section has a highest elevation and the lowermost surface section has a lowest elevation. The uppermost surface section, the at least two intermediate surface sections and the lowermost surface section define a continuously downward stepped path from the uppermost surface section to the lowermost surface section.