Silica bricks for coke ovens

Silica bricks for coke ovens

Silica bricks for coke ovens refer to silica refractory products with tridymite as the main crystal phase, which are used for building coke ovens. The following is a detailed introduction to silica bricks for coke ovens:

Main Raw Materials and Ingredients

Silica bricks for coke ovens are primarily made from carefully processed high-purity silica (SiO₂), typically with a SiO₂ content exceeding 94%. Their primary mineral phases are tridymite and cristobalite. During the production process, quartz sand and refractory clay are also used as auxiliary raw materials to ensure the quality and performance of the silica bricks.

Production Process

The production process for silica bricks for coke ovens typically includes the following steps:

Raw Material Preparation: Silica, quartz sand, and refractory clay are screened, crushed, and ground to ensure that their particle size meets the required specifications.

Mixing: The processed raw materials are placed in a mixer, a certain proportion of water is added, and agitation is performed to thoroughly mix and form a certain bond.

Molding: The mixed materials are formed using molds. Common molding methods include pressure molding, extrusion molding, and vibration molding.

Baking: The formed silica bricks are placed in a dedicated oven for an initial baking process to evaporate any residual moisture and organic matter, maintaining a stable shape.

Sintering: The baked silica bricks are heated in a high-temperature kiln, causing a chemical reaction between the silica and quartz sand to form a more stable silicate structure, thereby improving the bricks’ thermal shock and corrosion resistance.

Main Features

High Refractoriness: Silica bricks generally have a refractoriness of over 1650°C, with some even reaching over 1700°C. They can withstand the high operating temperatures of coke ovens, typically exceeding 1000°C.

Excellent Acid and Alkali Resistance: Silica bricks offer excellent resistance to both acidic and neutral molten materials.

High Strength: Silica bricks maintain excellent mechanical strength even at high temperatures and are not susceptible to deformation or cracking.

Thermal Shock Stability: Silica bricks are highly adaptable to temperature fluctuations and are less susceptible to cracking in environments subject to rapid temperature changes.

Thermal Conductivity: Silica bricks have excellent thermal conductivity, which helps evenly distribute heat within the oven and improves coke oven efficiency.

Applications

Silica bricks for coke ovens are primarily used in coke oven walls and roofs, providing insulation and fire resistance. They are the primary material for essential coke oven components (such as regenerator walls, chutes, combustion chambers, and carbonization chambers), accounting for 60% to 70% of all refractory bricks. Silica bricks are also widely used as thermal insulation and refractory materials in high-temperature kilns and industrial furnaces.

In summary, coke oven silica bricks, as a key material in the coke production industry, possess high refractoriness, excellent acid and alkali resistance, high strength, thermal shock stability, and good thermal conductivity. They play a vital role in coke oven construction, ensuring furnace durability and production efficiency. Furthermore, with the development of the global economy and the optimization and upgrading of industrial structures, the coke oven silica brick market is poised for even greater growth.