Refractory Materials Commonly Used in Glass-melting Furnaces

Refractories are the main components of glass melting furnaces, which have a decisive impact on glass quality, energy consumption, and product costs. The future of glass melting technology depends to a certain extent on the progress of refractory manufacturing technology and the improvement of product quality.

Refractory materials commonly used in glass melting furnaces are divided into four categories: casting refractory materials, sintered refractory materials, amorphous refractory materials, and heat insulation refractory materials. Each type of material contains several species. The chemical composition, physical properties, dimensional error, and appearance types of refractory materials should meet the national standards or industry standards, and the latest revised version should be selected, otherwise, they cannot leave the factory.

Silica bricks are widely used in glass-melting furnaces, and the main component is silicon dioxide (SiO2). Silica bricks used in glass melting furnaces require a SiO2 content of over 94%, a maximum operating temperature of about 1600~1650°C, and a density of 1.8~1.95g/cm3. The apparent porosity is required to be less than 22%, the larger the porosity, the worse the quality of the silica bricks. Silica bricks appear mostly white crystals, and the microcosmic composition is tridymite crystals. Since silica bricks undergo crystallization transformation at high temperatures, the volume expands, especially at 180-270°C and 573°C. Therefore, it is necessary to adapt to the crystallization transformation of silica bricks during the baking kiln and cold repair process and take appropriate measures such as elastic tie bars.

The main components of clay bricks for glass kilns are Al2O3 and SiO2, the content of Al2O3 is between 30%~45%, the content of SiO3 is between 51%~66%, the density is 1.7~2.4g/cm3, and the apparent porosity is 12%~21 %, the maximum operating temperature is 1350~1500℃. In the glass industry, clay bricks are used to build the bottom of the kiln. The pool wall of the working part and the passage, the wall of the regenerator, the wall, the lower checker brick, and the flue. As the temperature rises, the volume of clay bricks will also expand. When the temperature exceeds 1450 ° C, the volume will shrink again.

The main component of mullite brick is Al2O3, and its content is about 75%. Because it is mainly mullite crystallization, it is called mullite bricks. The density is 2.7-3 2g/cm3, the open porosity is 1%-12%, and the maximum service temperature is 1500~1700℃. Sintered mullite is mainly used for masonry walls of regenerators.