Slag Foaming Agent Reduces Steel Tapping Carryover
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Solution Overview
Problem
Existing steel tapping processes from furnaces often result in slag carryover, which contaminates the steel product with impurities, as the molten slag floats on top and can be drawn down through the taphole during tapping, despite previous attempts to address vortex formation and slag carryover through early stopping, skimming, or furnace design.
Innovation Solution
The process involves adding a foaming agent, such as calcium carbide or particulate, to the furnace during tapping, which forms slag foam, reducing its density and mass exiting the taphole by delaying vortex formation and maintaining a stable foam, thereby minimizing slag carryover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If tapping is stopped early to prevent slag carryover, then slag contamination is reduced, but tapping productivity decreases
Solution Approach 1:
The invention changes the physical state of slag by adding a foaming agent that transforms dense molten slag into low-density slag foam. This parameter change allows the slag to float higher on the steel and be excluded from the taphole flow, reducing slag carryover without requiring early tapping termination
Solution Approach 2:
The foaming agent acts as an intermediary substance added to the slag to modify its properties. The agent creates gas bubbles within the slag, transforming it into a foamy state that changes its density and flow characteristics, thereby preventing slag from being carried through the taphole while maintaining continuous tapping
2Manufacturing precision
If post-tap skimming is used to remove slag, then steel purity is improved, but additional processing time and complexity are required
Solution Approach 1:
The invention performs slag separation preliminarily during the tapping process itself by foaming the slag in-situ. The foamed slag naturally separates from the steel flow before reaching the taphole, eliminating the need for subsequent post-tap skimming operations and reducing overall process complexity
3Object-affected harmful factors
If an eccentric taphole is used to delay vortex formation, then slag carryover is reduced, but furnace design complexity increases
Solution Approach 1:
Rather than changing the geometric parameters of the taphole (as in eccentric design), this invention changes the physical parameters of the slag by foaming it. The foamed slag has different density and flow characteristics that prevent vortex formation and carryover, achieving the same effect without modifying the taphole structure
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
This approach effectively reduces the mass of slag exiting the taphole, resulting in purer steel being tapped and potentially providing additional benefits like extended oxide reduction and stable foam formation, with the foamed slag being less dense and thus lighter, reducing contamination in the steel product.
Implementation Method 1
adding a foaming agent in said furnace to form slag foam, wherein said foaming agent foams said slag providing for a reduction of slag mass from exiting said taphole
Implementation Method 2
the foaming agent may include calcium carbide
Data Source
AI summary
A process for tapping a steel furnace with a reduced amount of entrained slag is disclosed. During tapping, particles of a slag foaming agent are added. The foaming agent may include calcium carbide and/or other chemicals. The agent foams the slag to decrease its density during tapping and/or to disrupt initial vortex formation at the tap.