Fireclay bricks for coke oven tops are weakly acidic refractory clay bricks specifically designed for the top area of coke ovens. They are mainly used in parts of the oven top where the temperature is relatively low, the mechanical load is small, but thermal shocks occur frequently.

I. Characteristics

1. Chemical composition:

   - Al₂O₃ content ranges from 30% to 45%.

   - SiO₂ content is between 40% and 60%.

   - Fe₂O₃ content is ≤2.0-2.5%.

2. Refractoriness: It has a refractoriness of 1580°C-1750°C.

3. Softening temperature under load: The softening temperature under a load of 0.2 MPa is 1250°C-1400°C.

4. Thermal shock stability: It shows excellent thermal shock stability. It can withstand 10-25 water-cooling cycles at 1100°C, which enables it to adapt to the frequent hot-cold cycles during coal charging and coke discharging on the oven top.

5. Volume stability: The re-firing linear change rate is ≤±0.5%, meaning it is not prone to deformation and cracking at high temperatures.

6. Strength: The cold compressive strength is 20-40 MPa.

7. Corrosion resistance: It has strong resistance to acidic gas and soot erosion, but relatively weaker resistance to alkalis.

II. Application Areas on the Oven Top

1. Oven top platform: This is a non-load-bearing area with temperature fluctuations.

2. Lining bricks for riser pipes and bridge pipes.

3. Sealing walls of small flues and regenerators.

4. Areas around coal charging holes and sight holes (non-load-bearing areas): 

Note: High-alumina bricks are commonly used in load-bearing and high-impact areas on the oven top, such as the tracks of coal charging cars. 

III. Typical Physicochemical Properties (Standard Grades)

IV. Specifications and Dimensions

Standard bricks: 230×114×65mm

Special-shaped bricks for the coke-oven crown: Custom-made according to the furnace design (such as wedge-shaped bricks, springer bricks, key bricks, etc.)

V. Main Advantages

Good thermal shock stability: Better than silica bricks, it can adapt to the frequent and drastic temperature changes at the coke-oven crown.

High economic efficiency: With a wide range of raw materials, the cost is lower than that of high-alumina bricks and silica bricks.

Good workability: Easy to cut and lay, and has good air-tightness.

Resistant to acid corrosion: Can resist the corrosion of coke-oven gas, SO₂, etc.

VI. Selection Points

Temperature: Suitable for areas with a long-term temperature below 1350°C and large temperature fluctuations.

Load: Applicable to areas with small mechanical pressure.

Environment: For acidic atmospheres without strong alkaline slags.

Combination: Should be used in combination with high-alumina bricks in high-temperature and high-load areas at the coke-oven crown.