Brief Description
The function of steel ladle is delivering steel liquid from steel smelting furnace to refinery equipment or casting spots. Steel ladles can be divided into mould casting ladles and continuous casting ladles. The working condition of continuous casting steel ladles is harsher. Earlier, fireclay bricks and high alumina bricks are usually used as steel ladle lining bricks. But with the improvement of steel quality and steel species, high alumina bricks and chamotte bricks can’t meet production requirement, so alumina magnesia castable casted integral ladles and alumina magnesia carbon bricks gradually replaced them.
Converter Mould Casting Steel Ladle Castable
Converter steel smelting tempo is quicker, especially small converter for construction steel production, steel liquid supply is sufficient, ladles turnover period is shorter, ladle lining’s temperature drop is smaller. Castable used for integral casted ladles are: water glass binding alumina magnesia castable, bauxite magnesia castable, bauxite spinel castable, silicon micro powder binding high alumina castable, etc.
Parameters
| Item | Alumina magnesia castable | Alumina magnesia castable | High alumina castable |
| Application | Working lining | Working lining | Permanent lining |
| Al2O3 %≥ | 60 | 70 | 60 |
| MgO % ≥ | 12 | 10 | / |
| C % | / | / | / |
| Refractoriness ℃≥ | / | / | 1790 |
| RUL ℃ ≥ | 1200 | 1350 | / |
| LCR % (1400℃,2h) | 0~2 | 0~2 | 0~0.3 |
| Apparent porosity % ≤ | 23 | 25 | 18 |
| CCS MPa ≥ | 30 | 30 | 30 |
| Max. working temperature ℃ | 1700 | 1700 | 1650 |
Converter Continuous Casting Steel Ladle Castable
Converter continuous casting steel ladle’s turnover speed is faster, temperature fluctuation is smaller and working condition is better. So for small size converter ladles, bauxite magnesia castable is used to construct integral lining and can be patched to prolong service life.
For middle size and large scale ladles, corundum magnesia castable and corundum alumina magnesia spinel castable are usually used as ladle wall and bottom working lining. Slag line zone is usually built by magnesia carbon bricks. Castable which can be worked by gunning casting have been applied in some countries and have obtained very nice effect. Gunning castable includes alumina magnesia gunning castable, magnesia gunning castable, magnesia spinel gunning castable and so on.
Al2O3-MgO-C series Steel Ladle Castable
With the rapid development of steel smelting technique, especially with the application of continuous casting and out furnace refining techniques, the requirement on ladle refractory material is much higher. So chemical corrosion resistant, scouring resistant, slag erosion resistant, thermal shock resistant and high mechanical strength refractory materials such as Alumina magnesia carbon refractory materials are developed, which can produce magnesia alumina spinel and significantly enhance corrosion resistance and spall resistance of refractory material, greatly prolongs the service life of steel ladle.
① Alumina Magnesia Spinel Castable
Bauxite based alumina magnesia spinel castable contains certain ratio of magnesia alumina spinel, which makes castable’s corrosion resistance and spall resistance ability improved greatly, the performance is better than water glass bound alumina magnesia castable and get excellent using effect in all kinds of steel ladles. Bauxite based alumina magnesia spinel castable ‘s service life is 2-4 times of water glass bound alumina magnesia castable.
② High Grade Alumina Magnesia (Spinel) Castable
High grade alumina magnesia castable is mainly used for large scale and middle scale steel ladles. Raw materials of high grade alumina magnesia (spinel) castable include: corundum (fused corundum, sintered corundum), high purity fused magnesia sand, high purity alumina magnesia spinel (fused or sintered) and so on. Binders are: pure calcium aluminate cement, Al2O3 micro powder, high purity SiO2 micro powder and so on. The average service life of high class alumina magnesia castable casted 300t ladle is 258 times. When high grade alumina magnesia spinel castable is used in 90t LF refinery steel ladle, the service life is 138 times, erosion rate is 0.62mm/time.
Some steel factory also use castable pre-casted blocks, and the using effect is fairly good. For example, the service life of steel ladle alumina magnesia carbon bricks is 65 times, while the service life of high grade alumina magnesia spinel pre-casted blocks is 118 times, upper limits can reach to 126 times.
③ Alumina Magnesia Castable
After the development of alumina magnesia ramming mix, alumina magnesia castable is developed and first applied in small size steel ladles and obtained excellent effect. From 10t and 14t steel ladles tests, the average service life of water glass bound alumina magnesia castable is 109.7 times, more than 8 times of clay bricks. From 15t and 13t steel ladles tests, the service life is 53 times, while clay bricks’ service life is only 6~10 times. Integrally casted steel ladle inner lining technique is mainly used in small and middle size ladles, the service life of ladle linings can reach to 40~60 times, some small ladles can even reach to 90 times. Refractory material consumption and ladle linings cost is curtailed in large scale, and significant economic benefits is obtained. The physiochemical index of a typical water glass bound alumina magnesia castable is: 75.2% of Al2O3, 9.4% of MgO, 10.25% of SiO2, bulk density is 2.67~2.73g/cm3(110℃, 24h), cold compression strength is 14.9MPa.