High aluminum refractory brick anti-fouling method and cause of corrosion

When producing high-alumina refractory bricks, anti-fouling technology should be done. There are many anti-fouling technologies. Common wax coating is used, but the effect is not very satisfactory. The wax is not breathable. There is also the use of fluorine-containing compounds, but the price of this material It is high and the technology is not mature enough. The most ideal is silicone antifouling. High alumina refractory bricks will show corrosion damage in many cases, such as the high temperature of the furnace itself, or the structure change due to the penetration of slag, etc., The following details.

1. How to prevent high alumina refractory brick

1. Antifouling technology for waxes, organic coatings and hydrophobic surfactants: Waxes and organic coatings are relatively commonly used, antifouling treatment agents for the surface of high-alumina refractory bricks. But the effect has not been satisfactory. Although waxing is antifouling, the surface tension of the wax is large, and the time on the surface of the high-alumina refractory brick is short. And wax is a coating material, an airtight sealant.

2. Fluorine-containing low surface energy antifouling technology: fluorine-containing compounds have very low surface energy, and the surface tension of perfluoroalkanes is as low as 10mNm. The contact angle ratio with silicone is 110:101, so it has better anti-fouling and anti-stain ability. Although fluorine-containing compounds have good antifouling properties, they are relatively expensive. In addition, it is not very mature in the field of high-alumina brick anti-fouling technology, so the fluorine compound anti-fouling technology is rarely used at present.

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3. Silicone anti-fouling technology: The surface energy of high-alumina brick surface treatment agent is a very important factor in the surface anti-fouling performance. The low surface energy can prevent the adsorption of dust, microorganisms, water-based substances, particles, etc., and is easy to desorb under the action of external force. Silicone has a low surface tension, which can be as low as 21-22mNm. It is an ideal and widely used waterproof and antifouling treatment agent on the surface of high aluminum bricks.

2. Causes of corrosion of high-alumina refractory bricks

1. It is called thermal and mechanical peeling. It is caused by irregular cracks in the refractory lining due to the thermal stress of the furnace and mechanical stress. As a result, the lining of high-alumina refractory bricks is damaged too quickly.

2. It is called structural spalling. It is due to the penetration of slag and the heating surface, and the temperature fluctuation causes its structure to change. Therefore, a unique metamorphic structure layer is formed at the interface between the original layer and the metamorphic layer. Cracks parallel to the heating surface are generated, and the lining of the high-alumina refractory brick is stripped and damaged.

3. It is called melt flow. It is due to the reaction with molten steel, molten iron and molten slag to produce a substance with a lower melting point. The resulting melt flow or wear is mainly due to the corrosion of the surface layer due to the generation of liquid phase.

4. In addition, the overall liner is cracked due to the shrinkage of the high-alumina brick lining body, and the shrinkage of the brick liner due to refractory products during use. The resulting expansion or pull of the joint is also the main reason for the rapid local damage to the liner.