High Zirconia Refractory Material for Glass Furnaces

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Solution Overview

Problem

Refractory products for glass melting furnaces face challenges in balancing creep properties and thermal resistance, requiring improved materials that can accommodate dimensional changes and maintain stability under thermal variations without cracking.

Innovation Solution

A melted and cast refractory product with a specific composition, including varying percentages of ZrO2, HfO2, Al2O3, Na2O, K2O, B2O3, and other oxides, optimized to achieve excellent creep properties and resistance to thermal variations, manufactured through a controlled melting and cooling process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high zirconia content ( >85% ZrO2) is used to achieve corrosion resistance, then corrosion resistance is improved, but creep properties deteriorate

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidcreep resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters by introducing specific amounts of SiO2 (3-8%), Al2O3 (0.1-2%), and B2O3 (0.05-0.5%) alongside the high ZrO2 content. This parameter modification creates a composite refractory material that maintains corrosion resistance while improving creep resistance through the synergistic effects of multiple oxides working together

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite refractory material combining zirconia with silica, alumina, and boron oxide in specific proportions. This composite structure leverages the complementary properties of each component: ZrO2 provides corrosion resistance, SiO2 contributes to creep resistance, Al2O3 enhances thermal stability, and B2O3 improves chemical durability, achieving superior overall performance

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If sodium oxide is added to prevent zircon formation, then zircon formation is reduced, but thermal resistance deteriorates

Engineering Contradiction:
Improvezircon formation preventionVSAvoidthermal resistance
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The patent carefully controls the parameter of alkali metal oxide content by limiting Na2O+K2O to 0.05-0.5%, which is sufficient to prevent zircon formation but insufficient to significantly harm thermal resistance. This optimized parameter range resolves the contradiction between preventing zircon formation and maintaining thermal stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces B2O3 (0.05-0.5%) as an intermediary component that works synergistically with the limited alkali metal oxides to prevent zircon formation while having minimal negative impact on thermal resistance. The boron oxide acts as a mediator that enables zircon prevention at lower alkali content levels

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If creep properties are improved to accommodate dimensional changes, then dimensional stability is improved, but thermal variation resistance deteriorates

Engineering Contradiction:
Improvecreep capacityVSAvoidthermal variation resistance
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent employs a composite oxide system where SiO2 (3-8%) and Al2O3 (0.1-2%) work together to enhance creep resistance while B2O3 (0.05-0.5%) and the controlled alkali metal oxides provide thermal stability. This multi-component composite structure achieves balanced performance in both creep resistance and thermal variation resistance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the parameter ratios between different oxides, specifically maintaining B2O3/(Na2O+K2O) between 0.1 and 5.0 and Al2O3/(Na2O+K2O) between 2 and 20. These parameter optimizations ensure that creep resistance and thermal stability are achieved simultaneously rather than trade-off

Inventive Principle:
Principle #35Parameter changes

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 product exhibits enhanced creep capacity and thermal stability, allowing glass melting furnaces to maintain dimensional integrity despite temperature changes, with improved resistance to thermal variations and corrosion, outperforming reference products in terms of creep performance.

Implementation Method 1

The creep of a material under the action of a stress (compression, traction or bending) can be defined as the capacity of the material to deform visco-plastically, that is to say permanently, under the effect of this load.

Methodology Applied
Scientific EffectCreep: Creep

Implementation Method 2

good resistance to thermal variations makes it possible to form glass melting furnaces that are dimensionally stable over time despite thermal variations generated by furnace shutdowns

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2303799B1High zirconia refractory material
Publication Date: 2016.03.23 SAINT GOBAIN CENT DE RES & DEVS & DETUD EUROEN

AI summary

The invention relates to a molten cast refractory material comprising, in oxide wt % and totaling 100%: - ZrO2 + HfO2: the remainder of 100%; - SiO2: 3.5% to 6.0%; - Al2O3: 0.7% to 1.5%; - Na2O + K2O: 0.10 % to 0.43 %; - B2O3: 0.05% to 0.80%; - CaO + SrO + MgO + ZnO: 2O5:  2O3 + TiO2: 2O3/(Na2O + K2O) being greater than or equal to 3.5 and the wt % ratio for B2O3/(Na2O + K2O) being 0.3 to 2.5.