Introduction:
High-alumina refractory bricks are made from bauxite or kaolinitic clays. The definition high-alumina refractory bricks contain between 40 and 87.5 percent alumina. They are much harder and tougher than fireclay refractories at high temperatures and in basic environments. In addition, high-alumina refractory bricks exhibit better volume stability and abrasion resistance. High-alumina bricks are used in blast furnaces, blast-furnace stoves, and liquid-steel ladles etc.
The high alumina bricks are basically divided into three grades as per the amount Al2O3 they contain. These are
Grade I which includes Al2O3 for in the range of 75~81%
Grade II which includes Al2O3 for in the range of 60~75%
Grade III which includes Al2O3 for in the range of 48~60%
Top Grade which includes Al2O3 for in the range of 82~89%
Properties of High Alumina Bricks
The high alumina bricks are basically perfect and advanced refractory materials having a very high refractoriness up to 1750~1790, which is much higher than that of fire clay bricks and semi-silica bricks obviously.
The high alumina bricks are very durable in nature and are also well designed to be used in high-temperature area such as blast furnaces.
The high alumina bricks are usually constructed with higher refractoriness and low impurities.
These bricks include more Al2O3 content than that of other ones in the same category and hence can also be referred to neutral refractory material having resistance to acid and basic slag erosion.
Along with Al2O3 these bricks also comprise of SiO2 content which enhance the resistance to acid slag erosion much more..
Characteristic as follows:
a, refractoriness; high alumina bricks refractoriness are higher than clay and semi-silica brick refractoriness up to 1750 ~ 1790 ℃, belonging to high-grade refractory.
b, load softening temperature; high aluminum products because of high Al2O3, less impurities, less fusible vitreous formed, so load softening temperature is higher than the clay brick, but not formed mullite crystalline , so load softening temperature silica brick is still not high.
c, slag resistance; Al2O3 in alumina bricks are more close to neutral refractories, resistant to erosion of acid and alkaline slag slag, because it contains SiO2, so resistance to alkaline slag ratio of acid slag ability weaker.
Parameters
| Chemical Analysis (wt%) | Apparent Porosity (%) | Bulk density (g/cc)Min. | CCS (kg/cm2) | PLC (%) | PCE (℃/OC) Min. | RUL (Ta℃) | Application Area | |
| Al2O3 | Fe2O3 | |||||||
| 44-48 | 1.2-1.5 | 14-18 | 2.35 | 450-700 | -0.5 to 0.2 at 1450℃/2h | 1743/33 | 1460-1500 | Blast Furnace, Preheating Zone of Cement Rotary Kiln, Lime Kiln & Glass Tank Furnace. |
| – | – | 17-21 | 2.25 | 400-600 | -1.0 to 0.2 at 1450℃/2h | 1683/31 | 1390-1440 | Reheating Furnace Wall. |
| 47-50 | 2.6-3.5 | 17-21 | 2.32 | 450-650 | -0.8 to 0.4 at 1450℃/2h | 1717/32 | 1400-1450 | Preheating Zone of Cement Rotary Kiln & Reheating Furnace Wall. |
| 47-50 | 1.8-2.2 | 16-21 | 2.3 | 450-650 | -1.0 to 0.3 at 1450℃/2h | 1717/32 | 1400-1450 | Dense brick for Petro-Chemicals, Fertilizer Plants & Anode Baking Furnace. |
| – | – | 16-22 | 2.35 | 450-650 | -0.5 to 1.0 at 1450℃/2h | 1743/33 | 1430-1480 | Reheating Furnace Roof. |
| 52-55 | 2.9-3.9 | 17-22 | 2.42 | 450-650 | 1743/33 | 1400-1440 | Preheating Zone of Cement Rotary Kiln & Reheating Furnace Wall. | |
| 52-56 | 1.7-2.2 | 16-21 | 2.35 | 500-700 | -0.8 to 0.3 at 1500℃/2h | 1763/34 | 1450-1500 | Reheating Furnace Roof & Petro-Chemicals. |
| 56-59 | 1.0-1.5 | 17-21 | 2.35 | 400-600 | ±0.7 at 1500℃/2h | 1804/36 | 1500-1540 | Glass Tank Furnace & Frit Furnace. |
| 57-60 | 3.4-4.2 | 17-22 | 2.5 | 550-800 | -0.4 to 2.0 at 1450℃/2h | 1785/35 | 1420-1450 | Reheating Furnace Wall, Burning Ladle Back up. |
| 57-61 | 2.8-3.8 | 17-22 | 2.45 | 500-800 | -0.2 to 2.2 at 1500℃/2h | 1785/35 | 1430-1470 | Reheating Furnace Wall, Burning Zone of Cement Rotary Kiln & Ladle Back up. |
| 58-61 | 1.7-2.2 | 16-21 | 2.45 | 500-800 | -0.4 to 0.8 at 1500℃/2h | 1804/36 | 1470-1510 | Sulphur Furnace, Alakli Resistant Bricks for Cement Rotary Kiln & ladle Back up. |
| 59-61 | 0.9-1.1 | 14-18 | 2.45 | 600-800 | ±0.5at 1600℃/2h | 1820/37 | 1630-1670 | Blast Furnace Stove Checkers, Solid Wall Bricks & Glass Tank Furnace. |
| 61-63 | 1.2-1.7 | 14-18 | 2.45 | 500-800 | ±0.8 at 1500℃/2h | 1785/35 | 1500-1530 | Blast Furnace Stove Checkers, Solid Wall Bricks & Glass Tank Furnace. |
| 61-64 | 1.2-1.5 | 13-16 | 2.5 | 600-900 | ±0.5 at 1500℃/2h | 1804/36 | 1500-1550 | Blast Furnace Hearth, Non-Recovery Coke Oven, Glass Tank Furnace & Frit Furnace. |
| 62-64 | 0.9-1.2 | 12-15 | 2.5 | 650-900 | ±0.2 at 1500℃/2h | 1820/37 | 1500-1550 at 4kg/cm2 | Blast Furnace Hearth, Non-Recovery Coke Oven, Glass Tank Furnace. |
| 64-67 | 3.5-4.4 | 17-23 | 2.55 | 500-800 | 0.5 to 2.5 at 1450℃/2h | 1804/36 | 1440-1470 | Boiler, Cupola & Steel Foundry |
| 67-70 | 3.4-4.0 | 17-22 | 2.6 | 600-900 | 0.3 to 2.5 at 1450℃/2h | 1804/36 | 1460-1480 | Boiler, Cupola, Steel Foundry & Reheating Furnace. |
| 67-70 | 2.8-3.2 | 17-22 | 2.6 | 600-900 | 0.5 to 3.0 at 1500℃/2h | 1804/36 | 1460-1480 | Burning Zone of Cement Rotary Kiln & Steel Ladle. |
| 67-70 | 2.4-2.8 | 16-21 | 2.55 | 600-800 | 0.5 to 2.5 at 1500℃/2h | 1804/36 | 1460-1490 | Burning Zone of Cement Rotary Kiln & Steel Ladle. |
| 68-71 | 1.8-2.2 | 16-21 | 2.55 | 600-900 | 0.2 to 2.0 at 1500℃/2h | 1804/36 | 1470-1500 | Burning Zone of Cement Rotary Kiln & Steel Ladle. |
| 68-72 | 1.4-1.8 | 16-21 | 2.55 | 600-900 | -0.2 to 2.0 at 1500℃/2h | 1820/37 | 1500-1530 | Burning Zone of Cement Rotary Kiln, Lime Kiln & Steel Ladle. |
| 69-72 | 0.4-0.8 | 15-18 | 2.55 | 600-900 | -0.2 to 0.5 at 1600℃/2h | 1820/37 | 1650-1700 | Blast Furnace Hearth & Taphole, Lime Kiln, Glass Tank Furnace & Non-recovery Coke Oven. |
| 71-75 | 2.8-3.5 | 17-22 | 2.65 | 600-900 | 0.3 to 3.0 at 1500℃/2h | 1804/36 | 1470-1490 | Blast Furnace Hearth, Lime Kiln, Glass Tank Furnace & Non-recovery Coke Oven. |
| 74-77 | 2.8-3.5 | 17-22 | 2.72 | 700-950 | -0.5 to 2.5 at 1550℃/2h | 1820/37 | 1470-1500 | EAF Roof, Steel Rolling Mill & Steel Ladle. |
| 77-80 | 2.2-2.7 | 17-22 | 2.72 | 700-900 | 1820/37 | 1490-1520 | EAF Roof, Steel Rolling Mill, Steel Ladle & other high heat duty special applications. | |
| 78-81 | 1.5-2.0 | 15-19 | 2.75 | 750-1000 | 0.5 to 1.2 at 1550℃/2h | 1820/37 | 1520-1550 | EAF Roof, Steel Rolling Mill, Steel Ladle & other high heat duty special applications. |
| 78-81 | 1.5-2.0 | 14-18 | 2.8 | 800-1100 | 1820/37 | 1520-1550 | Phosphate-bonded bricks for Reheating Furnace Bottom & other high Abrasion Resistant applications. | |
| 82-85 | 1.4-1.8 | 15-19 | 2.8 | 750-1000 | -0.3 to 1.0 at 1550℃/2h | 1850/38 | 1540-1580 | Special high temperature, high abrasion & spalling resistant applications like Torpedo Ladle etc. |
| 82-85 | 1.4-1.8 | 13-17 | 2.85 | 850-1200 | 1850/38 | 1540-1580 | Non-wetting Phosphate-bonded bricks for Aluminium Melting & Holding Furnace, Reheating Furnace Bottom etc. | |
| 86-89 | 1.0-1.8 | 44911 | 2.9 | 900-1200 | -0.2 to 0.5 at 1500℃/2h | 1820/37 | 1580-1620 | Reheating Furnace Bottom (specially Coal-fired). |
Application of High Alumina Bricks
The high alumina bricks are mainly used in masonry in blast furnace, hot blast furnace, electric furnace roof, blast furnace, reflecting furnace, lining of rotary kiln. In addition, high alumina brick are widely used in open hearth furnace lattice brick, plug used in casting system, nozzle brick, etc. But the price of high alumina brick is higher than the clay brick, so we do not need high alumina brick when the clay brick can satisfy the demand.