Why is The Silicon Brick Damaged?

In reality, the actual use of the kiln is different, causing different degrees of damage to the silica bricks. Understanding the reasons for the damage of the silica bricks can effectively extend its service life. Next, Xuankun Refractory Material will explain the reasons for the damage of the silica bricks in detail.

Silica Brick for Hot Blast Stove

Corrosion and Penetration of Slag on Brick Body

The erosion of slag on silica bricks mainly includes three processes: penetration, dissolution, and erosion and abrasion. The corrosion of slag on silica bricks depends on the chemical composition of the slag and refractory materials, the operating temperature, and the melting point and fluid state of the slag, including the penetration of the dissolved slag into the refractory material, resulting in structural spalling.

Damage Caused by Thermal Stress

Spalling is caused by uneven stress on the silica brick. The reasons include: molten slag penetrates into the silica brick to form a metamorphic layer, causing structural stress; temperature fluctuations in the kiln cause thermal stress; the metal kiln shell causes mechanical stress; Creep stress generated at high temperature, etc.

Various stresses work together to cause cracks in the weak parts of the brick surface. The cracks continue to expand and penetrate each other to form cracks, and finally leave the brick body in a flaky or block form to spall, causing damage to the silica brick.

Mechanical Wear

The mechanical abrasion of silica bricks mainly comes from high-speed steam stripping and flowing molten slag, which not only strengthens the chemical reaction between molten slag and silica bricks, and removes the reaction products with low ash melting point from the surface of the brick, but also accelerates the deterioration of the brick body. , The peeling process of the cracked part

Cracks in the production process of silicon bricks are one of the reasons for the increase in the scrap rate. We need to find the reasons to reduce the formation of cracks in the silicon bricks. Next, let's take everyone to understand the reasons for the cracks on the surface of the silicon bricks.

Causes of Cracks on the Surface of Silica Bricks

Vertical Crack

Vertical cracks are perpendicular to the pressing direction of the product, generally along the height of the product. When the semi-dry machine is formed to produce products, it will cause "layer density" along the direction of pressure and cause uneven thermal expansion of the green body, resulting in larger thermal stress, generating cracks parallel to the density layer, so it is also called Machine pressure cracks are the most along the groove and tongue of the product.

Transverse Crack

Transverse cracks are parallel to the pressing direction of the product, generally along the thickness direction of the product, usually caused by uneven heating of each part during the firing of the product, and mostly appear on the fire surface outside the brick stack, especially the surface of the top layer of the product. .

Reticular Crack

Reticulated cracks are closed curves composed of several cracks. They are usually caused by excessively high temperature and large fluctuations, large internal thermal stress of the product, which has reached the failure stress of the product, and the microscopic inhomogeneity of the blank itself, which results in a network. crack. In addition, uneven mixing or raw material changes can also cause network cracks.

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