Types of insulation materials and commonly used refractory materials for glass kilns

Refractory materials are the primary and secondary components of glass 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 improvement of refractory material trading and production technology and the progress of product quality.

For large float lines,the composition of glass kilns usually consists of L-shaped hanging walls(usually using silicon bricks),melting parts(using electric melting bricks in areas in contact with glass liquid,using silicon bricks or electric melting bricks near the top),necks(usually using silicon bricks),cooling parts including ear pits(using corundum material in the center in contact with glass liquid,and silicon bricks or corundum in the center not in contact with glass liquid),annealing kilns The heat storage chamber is composed of high alumina bricks,clay bricks,and directly bonded magnesium chromium bricks.

The commonly used insulation materials are as follows:

Silicon bricks for glass kilns:

Silicon bricks are commonly used in glass furnaces,with the primary and secondary components being silicon dioxide(SiO2).Is SiO specified for silicon bricks used in glass furnaces?The water content is above 94%,the application temperature is around 1600~1650℃,and the density is 1.8~1.95g/cm3.The specified porosity is lower than 22%,and the larger the porosity,the worse the quality of the silica brick.The vast majority of silica bricks are white crystals in appearance,with a microscopic composition of quartz crystals.Due to the transformation of crystals and volume shrinkage of silica bricks at low temperatures,especially at around 180-270℃and 573℃,the crystal transformation is more severe.Therefore,appropriate measures such as loosening and tightening the tension strip should be taken to comply with the crystal transformation of silica bricks during the baking and cold repair processes.Silicon brick masonry should have shrinkage joints left.

Silicon bricks have a working temperature of about 200℃higher than clay bricks,but their corrosion strength to glass liquid and alkaline fly materials is weak.Therefore,they are used for constructing large arches,breast walls,and small furnaces.During masonry,materials such as high silica refractory mud or silica brick powder that are close to the composition of silica bricks should be used as bonding materials.

List of commonly used refractory materials for glass kilns

Clay bricks for glass kilns:

The main and secondary components of clay bricks are Al2O3 and SiO2.The water content of Al2O3 ranges from 30%to 45%,and SiO2 ranges from 51%to 66%.The density is 1.7-2.4g/cm3,the apparent porosity is 12%to 21%,and the application temperature is 1350-1500℃.In the glass industry,clay bricks are used to build water tanks in kilns.The side walls of the affairs department and access road,as well as the walls,arches,lower grid bricks,and flue of the heat storage room.As the temperature decreases,the volume of clay bricks also shrinks.When the temperature exceeds 1450℃,the volume will expand again.

High alumina bricks:

The main and secondary components of high alumina bricks are SiO2 and Al2O3,but Al2O3 should be greater than 46%.Made from corundum,high alumina bauxite,or sillimanite series minerals(Al?O?-SiO?)as raw materials.The density is 2.3~3.0g/cm3,the apparent porosity is about 18%~23%,and the application temperature is between 1500~1650℃.When the porosity of high alumina bricks is low,their corrosion resistance is better.High alumina bricks are mainly used to build the side walls of the cooling section,the arch of the heat storage chamber,the wall of the heat storage chamber,and other places.

Mullite bricks:

The main and secondary components of mullite bricks are Al2O3,with a content of around 75%.Because the main and secondary components are mullite crystals,they are called mullite bricks.The relative density is 2.7~3.2g/cm3,the initial porosity is 1%~12%,and the application temperature is 1500~1700℃.Sintered mullite is used primarily and secondarily for building walls of thermal storage chambers.Electric fused mullite is mainly used for building side walls,viewing holes,wall thickness,and other areas.

Fused zirconia corundum bricks:

Electric fused zirconia corundum bricks,also known as white iron bricks,are generally divided into three grades based on their zirconium content:33%,36%,and 41%.The zirconium corundum bricks used in the glass industry contain Al?O?50%~70%,ZrO?20%~40%relative density of 3.4~4.0g/cm3,apparent porosity of 1%~10%,and application temperature of around 1700℃.Electrically fused zirconia corundum bricks with a zirconium content of 33%and 36%are used for wall masonry,furnace side walls,flame space breast walls,small furnace nozzles,small furnace flat arches,small furnace stacks,tongue arches,and other places.Electrically fused beryllium corundum bricks with a zirconium content of 41%are used for the corners of wall side walls,flow holes,and other places where glass liquid has the most severe erosion and erosion on refractory insulation materials.This material is the most commonly used melting refractory insulation material in the glass industry.

Electric fused alumina bricks:

It mainly refers to electric meltingα、βCorundum,electric meltingβCorundum melting Fire brick,with the primary and secondary components of 92%~94%Al?O?Composition of corundum crystal phase,relative density 2.9-3.05g/cm

3.The apparent porosity is 1%~10%,and the application temperature is around 1700℃.

The resistance of fused alumina to glass dialysis can be very good,which is really a purification treatment for the wrong glass liquid.Widely used in glass furnaces,such as the side walls,pool bottom,flow channel,material channel side walls,and material channel pool bottom,which come into contact with glass liquid and require no purification of refractory insulation materials.

Quartz bricks:

The main and secondary components of quartz bricks are SiO2,with a maximum content of over 99%,a relative density of 1.9~2g/cm3,a fire resistance of 1650℃,and a working temperature of around 1600℃.They are acid resistant and corrosion-resistant,and are used for side walls of acidic boron glass and thermocouple hole bricks in flame spaces.

Alkaline fire-resistant insulation material:

Primary and secondary basic refractory insulation materials refer to magnesia brick,alumina magnesia brick,magnesia chrome brick and magnesia olivine brick.Its function is to resist the erosion of alkaline materials,with a fire resistance of 1900~2000℃.Widely used in the upper wall of the regenerative chamber,the arch of the regenerative chamber,the lattice structure,and the small furnace structure of glass furnaces.Insulating bricks for glass kilns:The heat dissipation area of glass furnaces is very large and the thermal efficiency is low.In order to save energy and reduce emissions,it is required to apply a small amount of insulation materials to temporarily suspend one-sided insulation.Especially in the side walls,pool bottom,arches,and walls of the heat storage room,melting section,and affairs section,insulation should be suspended to enhance heat removal.The porosity of insulation bricks is very large,the quality is very light,and the relative density does not exceed 1.3g/cm3.Because the heat conduction efficiency in the air is relatively poor,insulation bricks with a certain porosity will have insulation effect.Its thermal conductivity is slightly 2-3 times lower than that of general fire-resistant insulation materials,so the larger the porosity,the better the insulation effect.There are many different types of insulation bricks,including clay insulation bricks,silicon insulation bricks,high alumina insulation bricks,etc.