Zirconium corundum brick

Material: High-purity alumina (Al₂O₃); zircon (ZrSiO₄); desilicated zirconia (baddeleyite) Phases: Corundum + baddeleyite + glass phase Properties: Resistance to glass corrosion, no glass contamination

Application

Glass melting furnaces, electric furnaces, steel teeming gates, sodium silicate kilns, aluminum electrolytic cells, quartz melting furnaces, and phosphate furnaces.

Description

Fused cast zirconia-corundum bricks are produced by melting the following raw materials in an electric furnace:

High-purity alumina powder (Al₂O₃)
Zircon sand (ZrSiO₄)
Desilicated zirconia (ZrO₂)

After melting, the high-temperature molten material is poured into molds and then annealed with slow cooling to form a solid material. This electrofused zirconia-corundum brick is also known as:

Bakor
Bakor products
Fused cast AZS brick
AZS refractory
Fused AZS refractory brick

The abbreviation AZS comes from the Al₂O₃-ZrO₂-SiO₂ ternary system, where the chemical components are denoted by their initials in descending order of content:

Al₂O₃ (alumina) = A
ZrO₂ (zirconia) = Z
SiO₂ (silica) = S

Standard grades use this abbreviation. For example:

AZS-41 or BK-41 (indicating a fused zirconia-corundum brick with 41% ZrO₂ content)

Classification

Classification by ZrO₂ Content

AZS-33/БК-33: 33% ZrO₂
AZS-36/БК-36: 36% ZrO₂
AZS-41/БК-41: 41% ZrO₂

Classification by Casting Method

NC: Normal Cavity
OC: Oriented Cavity
RC: Reduced Cavity
FC: Full cut Cavity

NC

In the upper zones of melting basins (where there is no direct contact with molten glass).

OC

For products with a length >60 mm and for manufacturing sidewall bricks of glass melting furnaces.

RC

As sidewall bricks for glass melting furnaces

FC

Highly corrosion-stressed areas: Throat areas (outlet holes), Furnace thresholds (weirs), Corner zones of melting basin, Lining of working surfaces (directly exposed to molten glass)

Specifications

Brand		NC	OC	RC	FC
БК-33/AZS-33	Bulk Density g/cm3	≥3.55	≥3.65	≥3.65	≥3.75
БК-36/AZS-36	Bulk Density g/cm3	≥3.55	≥3.75	≥3.75	≥3.85
БК-41/AZS-41	Bulk Density g/cm3	≥3.7	≥3.9	≥3.85	≥3.95

Item	БК-33/AZS-33	БК-36/AZS-36	БК-41/AZS-41
Al2O3, %	≥50.00	≥49.00	≥45.00
ZrO2, %	≥32.50	≥35.50	≥40.50
SiO2, %	≤15.00	≤13.50	≤12.50
Na2O+K2O, %	≤1.30	≤1.35	≤1.3
Bulk Density g/cm3	≥3.75	≥3.85	≥4
Apparent Porosity %	≤1.2	≤1.0	≤1.2
Cold Crushing Strength MPa	≥200	≥200	≥200
Glass phase exudation temperature °С	≥1400	≥1400	≥1410
Bubble Evolution Rate 1300°С×10h	≤1.2	≤1.0	≤1.0
Static Corrosion Rate by Molten Glass 1500°С×36h (mm/24 h)%	≤1.4	≤1.3	≤1.2