Oxy Fuel Glass Furnace Solution - Zhengzhou Dezhong Corundum Materials Co., Ltd.

1. What Makes Oxy-Fuel Furnaces Different

Oxy-fuel combustion technology has become the standard for high-grade float glass, borosilicate glass, electronic glass, and solar/photovoltaic glass production. By replacing air with pure oxygen as the combustion medium, oxy-fuel furnaces achieve higher flame temperatures (up to 1700°C), lower energy consumption, and reduced NOx emissions - significant advantages for modern glass manufacturers.

However, this superior combustion performance comes at a cost to refractory materials. In a conventional air-fuel furnace, nitrogen (N₂, ~79% of air) dilutes the corrosive components in the combustion atmosphere. In an oxy-fuel furnace, there is no nitrogen - the atmosphere is concentrated, water-vapour-rich (H₂O ~50-60% vs ~10-15% in air-fuel), and alkali vapour concentration is dramatically higher.

Why Standard AZS is Not Enough for Oxy-Fuel Furnaces

In standard AZS, the glass phase contains SiO₂ (~15-16%) and Na₂O (~1.4%). Under oxy-fuel conditions, concentrated NaOH vapour reacts aggressively with the calcium-silicon phase (CaO·SiO₂) in the glass phase - forming additional glassy material within the brick and progressively dissolving SiO₂ particles.

This calcium-silicon phase (CaO·SiO₂) is the primary cause of accelerated AZS erosion in oxy-fuel atmospheres - a conclusion confirmed by materials research and validated in furnace performance data.

Result: shorter campaign life, increased glass contamination risk, and higher total cost of ownership.

Factor	Air-Fuel Furnace	Oxy-Fuel Furnace	Impact on Refractories
Flame Temperature	~1500–1550°C	~1600–1700°C	Faster glass phase softening
N₂ Content	~79%	~0%	No dilution of corrosive gases
H₂O Vapour	~10–15%	~50–60%	Enhanced alkali vapour transport
Alkali Vapour Conc.	Moderate	Very High	Accelerated glass phase exudation
CaO·SiO₂ Attack	Slow	Rapid	Primary erosion mechanism
Standard AZS	Reliable	Compromised	Shortened campaign life
DZ-AZS-33D/36D	-	Optimised	Extended campaign life

2. The DZR Solution: Low-Si, Low-Na AZS

Technology Background

Dezhong's technical team independently developed the DZ-AZS-33D and DZ-AZS-36D grades based on internationally advanced low-silicon, low-sodium oxidizing fused cast process technology. Starting from the proven AZS-36 oxidizing process foundation, our engineers systematically reduced SiO₂ content (to ≤11% and ≤10% respectively) and Na₂O content (to ≤1.05% and ≤0.9%) - directly targeting the calcium-silicon phase mechanism that drives oxy-fuel erosion.

This dual reduction produces a denser, more alkali-resistant glass phase with lower exudation tendency. The vitreous phase content is reduced from 21% (standard AZS-33) to just 14% - a 33% reduction - resulting in a stronger crystal matrix that maintains structural integrity under prolonged oxy-fuel exposure. The technology has been verified by national authorities and is protected by utility model patents.

Product Specifications

The following are the physicochemical property specifications for 33D and 36D, updated based on the latest product catalog data, for use in full-oxy-fuel combustion glass furnaces.

DZ-AZS-33D (Main Arch / Superstructure)
Chemical composition:

Item	Specification
ZrO2	≥32% (typical 33%)
Al2O3	Balance (typical 54.79%)
SiO2	≤11%
Na2O	≤1.05%
Fe2O3+TiO2	≤0.3% (typical 0.16%)

Phase composition: Glass phase 14%, Baddeleyite 32%, Corundum 54%; Porosity <1%

Performance: Exudation ≤1.5%, Corrosion ≤1.5 mm/24h, Bubbles ≤2.0%

Bulk density: ≥3.75 g/cm³; Recommended: WS/PT

DZ-AZS-36D (Side Wall / High-Erosion Zone)

Chemical Composition:

Item	Specification
ZrO2	≥36% (typical 36%)
Al2O3	Balance (typical 52.95%)
SiO2	≤10%
Na2O	≤0.9%
Fe2O3+TiO2	≤0.3% (typical 0.15%)

Phase composition: Glass phase 14%, baddeleyite 35%, corundum 51%; porosity <1%

Performance: Exudation ≤1.3%, corrosion ≤1.5 mm/24h, seed/bubble count ≤1.5%

Bulk density: ≥3.6 g/cm³; Recommended: WS/QX

3. Zone-by-Zone Material Selection

Full Furnace Material Map

Furnace Zone	Recommended Material	Casting Type	Key Reason
Crown	DZ-AZS-33D	WS / PT	Low SiO₂/Na₂O resists alkali atmosphere
Superstructure	DZ-AZS-33D	WS	Direct oxy-fuel gas exposure
Breast Wall	DZ-AZS-33D	WS	High alkali vapour zone
Front Wall	DZ-AZS-33D	WS / PT	Intense flame + thermal cycling
Back Wall	DZ-AZS-33D	WS	Alkali condensation zone
Tuckstone	DZ-AZS-33D	WS / PT	Thermal + alkali stress combined
Sidewall Waterline	DZ-AZS-36D	WS	Glass contact + oxy-fuel atmosphere
Lower Sidewall	DZ-AZS-36D	WS	High purity glass contact zone
Melter Bottom	DZ-AZS-41	WS	Max ZrO₂, full glass contact
Throat	DZ-AZS-41	WS / PT	Highest velocity glass flow
Regenerator Upper	DZ-AZS-33D Silica Brick	-	Alkali vapour cycling in oxy atmosphere
Hot Repair	Zero Expansion Silica Brick	-	No kiln shutdown required

4. Glass Type Application Matrix

Which Glass Types Need Oxy-Fuel Solutions

Glass Type	Why Oxy-Fuel	Key Challenge	DZR Recommendation
High-Grade Float Glass	Energy saving, lower emissions	Crown life, glass clarity	DZ-AZS-33D crown + AZS-36D sidewall AZS-33D
Borosilicate Glass	Higher melting temp needed	Boric acid vapour + alkali attack	DZ-AZS-33D/36D full superstructure
Electronic Glass	Ultra-pure glass required	Zero contamination tolerance	DZ-AZS-36D + AZS-41 full lining AZS-36D+AZS-41
Solar / PV Glass	Large output, energy efficiency	Long campaign, consistent quality	DZ-AZS-33D crown + AZS-36 sidewall
Optical Glass	Maximum purity requirement	Any glass phase contamination is critical	DZ-AZS-36D throughout superstructure
Container Glass	NOx reduction, energy cost	Higher furnace temp in oxy-fuel	DZ-AZS-33D crown + AZS-33 upper

5. Why Choose Dezhong for Oxy-Fuel Projects

Proprietary Technology - Not a Generic Product

DZ-AZS-33D and DZ-AZS-36D were independently developed by Dezhong's technical team - not adapted from a competitor's specification or purchased formula. The raw material selection, SiO₂/Na₂O reduction methodology, batching precision (±0.2%), and casting parameters are all proprietary. This technology is verified by national authorities and protected by utility model patents.

Production Quality - 8-Stage Control

Stage	Control Method	Why Critical for Oxy-Fuel
① Raw Material Inspection	Chemical + physical analysis of every batch	Low-Si, Low-Na raw materials verified at source
② Precision Batching	Computerised auto-batching, accuracy ±0.2%	Consistent SiO₂/Na₂O levels across all bricks
③ Oxidizing Process	Oxygen blowing electric arc furnace	Eliminates carbon contamination
④ 3D Mould Design 3D	CAD-optimised mould for minimum shrinkage CAD	Ensures dimensional accuracy for tight joints
⑤ Controlled Casting	4 casting types: PT / QX / ZWS / WS	WS void-free for all critical positions
⑥ Annealing	Controlled temperature reduction	Prevents micro-cracks
⑦ Cold Machining	CNC cutting, grinding, drilling	Precision dimensions for complex furnace geometry
⑧ Pre-Assembly	Full furnace set assembled and position-labelled	Zero surprises on site

Verified Quality - Credentials That Matter

✔ CMA-accredited national laboratory test reports accompany every shipment - SiO₂ and Na₂O verified analytically on every batch

✔ AZS-41 bulk density ≥4.0 g/cm³ - exceeds China national standard

✔ National 'Quality Products for Glass Furnace Industry' certification

✔ Multiple utility model patents for low-silicon, low-sodium AZS production technology

✔ Products exported to many countries: Russia, Middle East, Iran, South Korea, Germany, Turkey, Southeast Asia, India, Egypt

Full-Project Service Package

Service	What We Provide	Benefit to You
Technical Assessment	Alkali exposure analysis for each furnace zone	Right material for each position
Furnace Design	Full glass furnace design and 3D layout drawings	Optimised design from the start
Material Specification	Grade, casting type, orientation per position	No guesswork - science-based selection
Pre-Assembly	Complete set assembled, labelled, verified	Faster installation, zero errors
Certified Documentation	CMA test reports for every batch	Audit-ready quality assurance
Hot Repair Guidance	Zero expansion silica brick for no-shutdown repair	Minimise downtime during campaign
Technical Support	Available throughout furnace campaign	Expert support when you need it