1. Rebonded Magnesia Bricks Description
Rebonded magnesia bricks use fused magnesia sand as raw material, so rebonded magnesia fire bricks are also call fused magnesia bricks. Compared with sintered magnesia sand, fused magnesia sand has higher MgO content, higher bulk density, lower porosity and larger crystalline size. Both fused magnesia sand and high purity magnesia sand adopt special grade magnesite (contains more than 47% of MgO ) as raw material. The purity of high purity magnesia sand can reach to 98%, while the purity of fused magnesia sand can reach to 98.5% to 99%.
Rebonded magnesia bricks should be molded by high pressure and sintered at super high temperature( 1800℃). To enhance the resistance ability of metallurgical slag corrosion, rebonded magnesia bricks can be treated with pitch in vacuum atmosphere. Rebonded magnesia bricks have high density, good high temperature performance and better hydration resistance than ordinary magnesia bricks.
Rebonded Magnesia Bricks Physiochemical Index
| Item | SMZ-96 | SMZ-97 | SMZ-98 | SMZ-97 oil immersed | SMZ-98 oil immersed |
| MgO % | 96.3 | 97.1 | 97.7 | 93.03 | 93.11 |
| CaO % | 1.3 | 0.97 | 0.63 | 1.05 | 0.82 |
| SiO2 % | 1.2 | 0.97 | 0.58 | 0.73 | 0.8 |
| Al2O3 % | 0.3 | 0.32 | 0.22 | 0.26 | 0.34 |
| Fe2O3 % | 0.8 | 0.89 | 0.59 | 0.68 | 0.56 |
| Apparent porosity % | 15 | 14 | 14 | 1 | 1 |
| Bulk Density % | 3 | 3.1 | 3.1 | 3.23 | 3.25 |
| Cold crushing strength Mpa | 90 | 90 | 90 | 120 | 120 |
| Refractoriness under load ℃ | 1700 | 1700 | 1700 | 1700 | 1700 |
Rebonded Magnesia Bricks Applications
Rebonded magnesia bricks are usually used at tap hole of steel smelting furnace, where slag corrosion and abrasion are severe. Rebonded magnesia bricks are also used at nonferrous metals smelting furnaces slag line part, iron mixing furnace tap hole, upper part of glass kiln regenerative chamber checker and combustion chamber.
Rebonded magnesia bricks are expensive, to decrease production cost, fused magnesia sand is added into sintered magnesia sand to make semi rebonded magnesia bricks, which can not only meet using requirement, but also have a relative lower price than rebonded magnesia bricks.
2. Chemical Bonded Magnesia Bricks Description
Chemical bonded magnesia bricks are magnesia bricks which are bonded by chemical binder without high temperature sintering, are also called unburned magnesia bricks. Because chemical bonded magnesia bricks don’t need sintering ,production craft is simpler and price is lower, the performance is close to sintered magnesia bricks, but as there is no ceramic bonding, the mechanical strength is low at 800~1300℃, which may cause spalling or damage during using, what’s more, the chemical binder may form low melting point material and lead to the decrease of high temperature strength and slag corrosion resistance. Chemical bonded magnesia bricks used to used at electric furnace side wall, glass kiln regenerative chamber checker, cement kiln lining, etc, but now is replaced by burned magnesia bricks and seldom used.
RS Kiln Refractory Introduction
RS Kiln Refractory was founded in the early 1990s. With more than 20 years of innovation and technical reformation, RS brand refractory products such as mullite brick, carbon brick, alumina brick, magnesia brick, silica brick, corundum brick, clay brick, high alumina castable, low cement castable, ceramic fiber textiles have exported to more than 60 countries and regions, our refractory products are tested by numerous customers and are trustworthy.
If you have any refractory material question or requirement, please feel free to contact us.
