Stabilized Zirconia Lance Nozzle Insert for Calcium Wire Injection
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Solution Overview
Problem
The challenge in steel production is efficiently adding calcium to molten ferrous material due to its low density, volatility, and reactivity, leading to inadequate residence time and inefficient treatment, with existing methods causing turbulence and poor calcium utilization.
Innovation Solution
A refractory lance nozzle insert made of stabilized zirconium oxide, graphite, and resin is used to feed a calcium-containing wire below the molten metal surface, ensuring longer operational life and improved corrosion resistance, allowing for deeper penetration and longer residence time of calcium globules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If calcium-containing wire is fed through the upper surface of the melt, then large flows of gas are not needed, but the high volatility of calcium causes inefficient utilization and rapid rise to surface
Solution Approach 1:
The invention transitions from surface-level calcium addition to deep-subsurface addition by immersing the lance outlet below the melt surface. This dimensional change in delivery location allows calcium to be introduced at depth where it can dissolve and react effectively without immediate volatilization or rapid rise to the surface, thereby improving utilization efficiency while maintaining operational simplicity.
2Ease of operation
If calcium wire does not penetrate to sufficient depth, then addition is simple, but residence time is low and treatment is non-uniform
Solution Approach 1:
By positioning the lance outlet at a sufficient depth below the melt surface, the invention enables calcium wire to penetrate deep into the melt column. This deep penetration ensures adequate residence time for calcium to dissolve and react uniformly throughout the melt, while the simple wire-feeding mechanism remains unchanged.
3Productivity
If inert gas is injected to propel calcium powder, then powder can be injected into melt, but high turbulence is generated causing excessive exposure to atmosphere
Solution Approach 1:
The invention extracts and eliminates the need for inert gas injection by using a mechanically fed calcium wire system. The wire is fed directly through the lance into the melt without requiring gas flow to propel it, thereby avoiding the turbulence and atmospheric exposure problems associated with gas-based powder injection methods.
4Productivity
If calcium desolidifies at ferrostatic pressures lower than vapor pressure, then calcium can be added, but large gas bubbles form and rise rapidly causing turbulence
Solution Approach 1:
By delivering calcium wire to a deep subsurface location, the invention ensures that calcium desolidifies at depths where ferrostatic pressure is higher than vapor pressure. This pressure condition prevents the formation of large gas bubbles, allowing calcium to remain dissolved or form fine, non-turbulent bubbles that rise slowly, thereby eliminating surface turbulence while maintaining efficient addition.
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 solution provides a more efficient and uniform treatment of molten ferrous material by extending calcium residence time, reducing turbulence, and enhancing the durability of the lance nozzle insert, leading to improved calcium utilization and operational efficiency.
Implementation Method 1
Because of the buoyancy of the wire, resulting from its lower density than that of the melt, the calcium wire bends
Implementation Method 2
The lance nozzle insert is made of a material comprising stabilized zirconium oxide, graphite and resin... ensuring longer operational life and improved corrosion resistance
Implementation Method 3
the calcium wire bends. The desolidification of calcium at a ferrostatic pressure greater than its vapor pressure leads to the creation by melting of liquid calcium globules, which rise much more slowly through the melt
Data Source
AI summary
A lance nozzle insert for a refractory lance for feeding an additive wire into a quantity of molten metal below the surface of the molten metal surface is made of a material comprising stabilized zirconium oxide and graphite substantially increasing the corrosion resistance of the lance nozzle insert.