MgO-C Refractory Nozzle for High-Temperature Melt
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Solution Overview
Problem
Existing gas blowing nozzles in high-temperature melt refining vessels experience significant damage due to thermal shock, erosion, and wear, leading to reduced durability and lifetime, with previous improvements failing to provide effective measures.
Innovation Solution
A refining vessel with a gas blowing nozzle featuring a carbon-rich MgO-C refractory central portion and an ordinary-carbon-content MgO-C refractory outer portion, designed to reduce thermal stress and wear resistance, where the central refractory has a specific outline and carbon content to optimize thermal conductivity and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a carbon-containing refractory is used in the gas blowing nozzle to reduce thermal shock, then thermal shock resistance is improved, but wear resistance deteriorates
Solution Approach 1:
The patent applies local quality by creating a radial gradient in carbon content within the refractory nozzle. The inner portion (facing the molten metal) has lower carbon content (10-30 mass%) to provide wear resistance, while the outer portion has higher carbon content (40-70 mass%) to provide thermal shock resistance. This spatial variation in material properties allows each region to be optimized for its specific functional requirements.
Solution Approach 2:
The patent uses composite materials by combining MgO and carbon in varying proportions to create a refractory nozzle with differentiated properties. The composite structure allows the material to exhibit both thermal shock resistance (from the high-carbon outer layer) and wear resistance (from the low-carbon inner layer), resolving the contradiction between these two properties.
2Temperature
If the carbon content in the refractory is increased to reduce thermal shock, then thermal conductivity is improved, but corrosion resistance deteriorates
Solution Approach 1:
The patent applies local quality by creating a radial gradient in carbon content within the refractory nozzle. The inner portion (facing the molten metal) has lower carbon content (10-30 mass%) to provide wear resistance, while the outer portion has higher carbon content (40-70 mass%) to provide thermal shock resistance. This spatial variation in material properties allows each region to be optimized for its specific functional requirements.
3Ease of manufacture
If a single-carbon-content refractory is used to simplify manufacturing, then ease of manufacture is improved, but durability deteriorates
Solution Approach 1:
The patent applies parameter changes by varying the carbon content parameter radially through the refractory nozzle thickness. The carbon content is controlled to be 10-30 mass% in the inner portion and 40-70 mass% in the outer portion. This parameter variation optimizes both durability (through tailored properties in each region) and manufacturability (through a systematic gradient structure that can be achieved in single-piece castings).
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 significantly reduces cracking and wear due to thermal shock, extending the lifetime of the gas blowing nozzle and improving durability by forming a protective slag film on the operating surface.
Implementation Method 1
the central refractory being formed of a MgO—C refractory having a carbon content of 30 to 80 mass %, and the outer refractory being formed of a MgO—C refractory having a carbon content of 10 to 25 mass %
Implementation Method 2
forming a protective slag film on the operating surface
Data Source
AI summary
A refining vessel for high-temperature melt includes a refractory for gas blowing nozzle that includes a central refractory embedded with metal tubules, and an outer refractory circumferentially surrounding the central refractory. The refractory for gas blowing nozzle has a horizontal projection on which a minimum radius of an imaginary circle encompassing all the metal tubules embedded in the central refractory is R (mm), wherein the central refractory has an outline that falls between one circle that is concentric with the imaginary circle and has a radius of R+10 mm, and another circle that is concentric with the imaginary circle and has a radius of R+150 mm. The central refractory is formed of a MgO—C refractory having a carbon content of 30 to 80 mass %, and the outer refractory is formed of a MgO—C refractory having a carbon content of 10 to 25 mass %.