Vacuum Degassing Ladle Slag Foaming Control
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Solution Overview
Problem
During the vacuum degassing of molten steel, vigorous chemical reactions at the interface between the molten metal and slag can lead to rapid foaming, causing the slag to overflow from the ladle, resulting in significant slag loss and disruption to the purification process.
Innovation Solution
An apparatus and method that utilize a radar transceiver to monitor the slag surface level and control the vacuum pumping rate, automatically reducing the evacuation rate when foaming occurs to prevent overflow, and adjusting it back when the slag level recedes, thereby managing the foaming process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the vacuum pumping rate is increased to improve degassing efficiency, then the purification speed increases, but the slag foaming intensifies and may overflow from the ladle
Solution Approach 1:
The patent implements a feedback control system where a gauge continuously monitors the slag surface level in the ladle. When the slag level rises indicating foaming, the control means automatically reduces the vacuum pumping rate to suppress foaming. When the slag level recedes, the pumping rate is increased again to maintain degassing efficiency. This closed-loop feedback mechanism dynamically balances purification speed with foaming control.
Solution Approach 2:
The vacuum pumping rate is made dynamic rather than fixed. The system continuously adjusts the pumping rate based on real-time slag level conditions. The control means modulates the vacuum pumping arrangement to operate at different rates, increasing efficiency when slag is stable and reducing rate when foaming occurs, thereby adapting to changing process conditions.
2Reliability
If the vacuum pressure is steadily reduced to enhance impurity removal, then the purification process improves, but vigorous chemical reactions occur at the metal-slag interface causing rapid gas generation and slag inflation
Solution Approach 1:
The feedback control system detects the onset of vigorous chemical reactions through slag level monitoring. When rapid gas generation causes slag to rise, the gauge signals the control means to reduce vacuum pressure, which in turn suppresses the intensity of chemical reactions at the metal-slag interface. This prevents runaway foaming while maintaining effective purification.
Solution Approach 2:
The system takes preliminary anti-action by monitoring slag level trends and proactively reducing vacuum pressure before slag overflow occurs. The control means anticipates potential foaming problems by detecting early signs of slag level rise and adjusts pumping rate in advance to prevent harmful foaming and overflow.
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
Prevents slag overflow by controlling the degassing rate based on real-time slag surface monitoring, maintaining process stability and minimizing slag loss.
Implementation Method 1
the ladle is positioned within a degassing chamber connected to a vacuum pumping arrangement for evacuating the chamber. The pumping arrangement is operated to subject the chamber to a steadily decreasing pressure (increasing vacuum), which causes gaseous and metallic impurities to leave the liquid phase and be evacuated from the atmosphere above the melt.
Implementation Method 2
a gauge for outputting a signal indicative of the level of a surface of the slag
Data Source
AI summary
To degas a molten metal, a receptacle containing the molten metal and a layer of slag over the molten metal is positioned in a chamber, and the chamber is evacuated. As the pressure in the chamber reduces, gas is generated at the interface between the molten metal and the slag, which causes the slag to foam. To inhibit overflowing of slag from the receptacle, a gauge outputs a signal indicative of the level of the surface of the slag, and the rate of evacuation of the chamber is reduced to reduce the rate of gas generation.