Refractory BricksAlumina–silica and corundum bricks

High Alumina Brick

High alumina brick is a neutral alumina–silica refractory brick with an Al₂O₃ content of at least 48 %, graded by alumina content. It has a degree of corrosion resistance to both acidic and alkaline slag, high cold crushing strength, good resistance to erosion, strong resistance to penetration and a high refractoriness under load.

Neutral alumina–silica refractory brick with resistance to both acidic and alkaline slag, high cold crushing strength and high refractoriness under load. Six grades from LZ-48 to LZ-80.

Grades / types: LZ-80, LZ-75, LZ-70, LZ-65, LZ-55, LZ-48

Product overview

RISING REFRACTORY supplies high alumina brick in six grades, LZ-80, LZ-75, LZ-70, LZ-65, LZ-55 and LZ-48, each named for its minimum Al₂O₃ content. Across the published specification the higher-alumina grades carry the higher strength and load-bearing figures: cold crushing strength rises from ≥40 MPa at LZ-48 to ≥70 MPa at LZ-80 and refractoriness under load from ≥1420 ℃ to ≥1530 ℃, while apparent porosity stays within ≤21–24 %.

Within the refractory brick family, high alumina brick follows the fireclay bricks: the low-porosity and low-creep clay bricks are specified at a lower Al₂O₃ content. The comparison table below sets the published values of the clay bricks beside the six high alumina grades.

In the industry selection matrices published on this site, high alumina brick is specified for hot blast stove and blast furnace walls and regenerator checker work, coke ovens and the permanent lining of steel ladles in steel plants, for the glass kiln bottom and the lower part of the regenerator in glass plants, and in the material range for zinc, lead and nickel smelting.

Key characteristics

Neutral material: resists both acidic and alkaline slag
High cold crushing strength
Good erosion resistance
Strong resistance to penetration
High refractoriness under load

Technical data

Physical and chemical specification
Property	Unit	LZ-80	LZ-75	LZ-70	LZ-65	LZ-55	LZ-48
Al₂O₃	%	≥80	≥75	≥70	≥65	≥55	≥48
Apparent Porosity	%	≤21	≤24	≤24	≤24	≤22	≤22
Cold Crushing Strength (CCS)	MPa	≥70	≥60	≥55	≥50	≥45	≥40
Refractoriness Under Load, 0.2 MPa (RUL)	℃	≥1530	≥1520	≥1510	≥1500	≥1450	≥1420
Permanent Linear Change (PLC)	%	-0.4~0.2 (1500℃×2h)	-0.4~0.2 (1500℃×2h)	-0.4~0.1 (1450℃×2h)	-0.4~0.1 (1450℃×2h)	-0.4~0.1 (1450℃×2h)	-0.4~0.1 (1450℃×2h)

Published values compared

The range each product’s published grades span. An empty cell means that product publishes no value under this label; nothing is carried across from another product.

Property	Unit	High Alumina Brick	Low-Porosity Clay Brick	Low-Creep Clay Brick
Al₂O₃	%	≥48–80	≥42–45	≥40–45
Apparent Porosity	%	≤21–24	≤12–17	≤15–22
Cold Crushing Strength (CCS)	MPa	≥40–70	≥55–80	≥35–60
Refractoriness Under Load, 0.2 MPa (RUL)	℃	≥1420–1530	≥1420–1500	—

Where Refractories Are Used

Selection guide

Answers drawn from the published specification and the industry selection matrices, for engineers comparing this product before a quotation.

What is high alumina brick?: High alumina brick is a neutral alumina–silica refractory brick with an Al₂O₃ content of at least 48 %, graded by alumina content. It resists both acidic and alkaline slag and combines high cold crushing strength, good erosion resistance, strong resistance to penetration and a high refractoriness under load.
Which Al₂O₃ grades of high alumina brick are available?: Six grades, named for their minimum Al₂O₃ content: LZ-80 (≥80 %), LZ-75 (≥75 %), LZ-70 (≥70 %), LZ-65 (≥65 %), LZ-55 (≥55 %) and LZ-48 (≥48 %).
How do the published grades differ?: As the Al₂O₃ content rises from LZ-48 to LZ-80, the published cold crushing strength rises from ≥40 MPa to ≥70 MPa and the refractoriness under load from ≥1420 ℃ to ≥1530 ℃; apparent porosity is specified at ≤22 % for LZ-48 and LZ-55, ≤24 % for LZ-65 to LZ-75 and ≤21 % for LZ-80. Permanent linear change is stated after two hours at 1450 ℃ (LZ-48 to LZ-70) or 1500 ℃ (LZ-75 and LZ-80).
What is the difference between high alumina brick and fireclay brick?: Both are alumina–silica bricks from the same family. The fireclay bricks in the catalogue, the low-porosity and low-creep clay bricks, are specified at a lower Al₂O₃ content and for low apparent porosity or low creep under load; high alumina brick starts at Al₂O₃ ≥48 % and is specified for refractoriness under load from ≥1420 ℃ to ≥1530 ℃. The comparison table on this page sets the published values side by side.
Where is high alumina brick used?: In the industry selection matrices published on this site, high alumina brick is specified for hot blast stove and blast furnace walls and regenerator checker work, for coke ovens and for the permanent lining of steel ladles in steel plants; for the glass kiln bottom and the lower part of the regenerator in glass plants; and in the material range for zinc, lead and nickel smelting.
What information is needed to select a grade?: The equipment and the lining zone, the operating temperature and atmosphere, what the brick is in contact with (slag, melt or atmosphere), the shape and dimensions or a drawing, the quantity and the delivery destination. The technical team confirms the grade against these service conditions; no single Al₂O₃ figure is published as a rule for a given duty.

Where this product is specified

Every position in the published industry selection matrices that names this product, with the source document’s own refractory term.

Industry	Process / equipment	Zone	Source term
Steel & Iron	Hot Blast Stove	Regenerator checker work	High Alumina Checker Brick For Hot Blast Furnace
Steel & Iron	Hot Blast Stove	Stove and blast furnace walls	High Alumina Brick
Steel & Iron	Steel Ladle	Permanent lining	Sintered Magnesia Brick / High Alumina Brick
Steel & Iron	Coke Oven and CDQ	Coke oven	High Aluminum Brick
Nonferrous Metals	Zinc, Lead and Nickel	Material range listed for these industries	High Alumina Bricks
Glass	Melting Tank	Glass kiln bottom	Ultra-high Alumina Brick
Glass	Regenerator	Lower part of the regenerator	Ultra-high Alumina Brick