Application of refractory materials in various parts of glass kiln tank kiln

Application of refractory materials in various parts of glass kiln tank kiln

Refractory materials used in glass kiln tank kilns are generally divided into the following 9 categories, including tank wall bricks, tank bottom bricks, charging tank bricks, flow hole bricks, cooling tank and forming tank bricks, kiln roof and breast wall bricks, front wall and lattice wall bricks, small furnace bricks, and refractory materials for special parts. The editor will give you a detailed explanation of these 9 categories. 

① Tank wall bricks

The ideal tank wall brick material for tank kilns that melt sodium calcium silicon materials and boron-containing materials is electric flame zirconium corundum bricks. Tilt casting bricks with a zr02 content of 33% are placed below with the gate facing outward. When melting alkali-free or low-alkali glass fibers, due to heavy acid erosion, AZS bricks or dense zircon bricks should be used as the material of the tank wall bricks, or fused quartz bricks can also be used.

② Tank bottom bricks

The tank bottom bricks are required to be wear-resistant and have integrity. Now a multi-layer composite tank bottom structure is mostly used. The multi-layer structure is generally built with an insulation layer under the main layer-the clay bricks. A protective layer and a wear-resistant layer are set on the top of the clay brick. The protective layer is made of corundum sand ramming material or fused corundum ramming material. The wear-resistant layer is on the protective layer to protect the bottom of the ramming pool and directly contact the glass liquid. The fused AZS bricks with good corrosion resistance and wear resistance are often used. The effect of this composite pool bottom structure is: reducing heat dissipation loss and extending the life of the pool bottom. When melting glass containing heavy metal elements (such as lead glass) or heavily corroded glass (such as milky white glass), in order to prevent leakage, a protective layer and a wear-resistant layer can be added on the original protective layer and wear-resistant layer. The original protective layer and wear-resistant layer are also called secondary paving layers, which can be made of sintered AZS bricks or zircon bricks.

③Feeding pool bricks

The charging pool bricks are eroded by the powder and glass liquid, the wear of the material layer, the scouring of the liquid flow and the influence of the flame, so the damage is more serious. High-temperature wear-resistant and corrosion-resistant materials are required, and zrO2-containing materials without shrinkage cavities are often used. 41% electric flame zirconium corundum bricks, and increase the brick thickness and strengthen air cooling. Except for the corner bricks, other parts can use ordinary cast AZS-33 bricks. The lower layer of the charging pool brick liquid can consider using cast kaolin bricks.

④ Flow hole bricks

The glass liquid in the flow hole of the pool kiln has the largest flow rate and obvious convection, so it is severely worn and accelerates erosion. Therefore, the flow hole cover bricks should use AZS-41 bricks without shrinkage holes, and the flow hole side wall bricks should preferably use the same material as the cover bricks, at least Bricks without shrinkage cavities should be used. Fused quartz bricks are used when melting borosilicate glass.

⑤ Bricks for cooling pools and forming pools

The cooling and forming pools contain melted and clarified glass liquid, which has entered the later stage of the melting process. At this time, no defects (including bubbles, streaks, and stones) should be caused to the glass liquid. The cooling pool needs to use AZS-33 bricks produced by the oxidation method, which has a high glass phase precipitation temperature and will not bring bubbles to the glass liquid. The forming pool (such as the feed channel) should use electric melting α-β AI203 bricks or fused a-AI203 bricks.

⑥ Bricks for kiln roof and breast wall

The damage characteristics of this part of the brick body are corrosion (mainly alkaline sulfate condensation, forming honeycomb corrosion) and burning. It is required to use materials that are extremely stable to alkali vapor at high temperature, and have high load softening temperature and creep resistance. You can choose silica bricks, high-quality silica bricks and fused AZS-33 bricks.

⑦ Bricks for front wall and lattice wall

These are the front and rear walls of the melting space. They also have two damage characteristics: corrosion and burning. In addition, the front wall is subject to wear and corrosion of the batch material and erosion of the overflow flame. It is one of the weak parts of the tank kiln. At present, fused AZS-33 bricks are used, and high-quality silica bricks and sintered AZS bricks are also used in combination (such as L-shaped hanging walls). In addition to using high-quality silica bricks, the front wall It also needs to be combined with air cooling.

⑧ The bricks for small furnaces can be divided into the crater, small furnace neck, nozzle bricks and other parts. The bricks for small furnaces are required to be resistant to high temperature, erosion, scouring, and thermal shock. If the furnace gas is burned (the heat load is small), silica bricks or even kaolin bricks can be used. If high calorific value fuel is burned (the heat load is large), the crater arch bricks, crater side wall bricks, bottom plate bricks, inclined ballast interlayer bricks, tongue bricks and nozzle bricks are fused AZS-33 bricks, and the bottom plate can also be sintered dense corundum bricks

⑨ Selection of refractory materials for special parts

There are some special parts on the pool kiln masonry, such as bubbling holes, kiln sills, electrode holes, inspection holes, measuring holes, etc. They have special uses and unique damage characteristics. Bubble hole bricks will be strongly worn and eroded by the rapid circulation of liquid caused by bubbling. The large temperature difference between the inner and outer surfaces of the bubbling hole bricks will produce large mechanical stress, which is easy to cause cracks. Kiln sill bricks will also be damaged by intense high-temperature liquid flow. Both types of bricks can be made of shrinkage-free fused zirconium corundum bricks containing 41% Zr02 produced by oxidation method. The electrode hole bricks are strongly eroded by the circulating liquid flow around the electrode, and the large temperature difference in the bricks caused by electrode cooling produces large mechanical stress, resulting in radial cracks around the brick holes. Therefore, the bricks are required to be corrosion-resistant and wear-resistant, as well as have certain thermal shock resistance and high electrical resistance. When selecting materials, in addition to considering their electrical properties, the conductivity of the glass liquid and the arrangement of electrodes should also be considered. Generally, shrinkage-free fused zirconium corundum bricks containing 41% Zr02 produced by oxidation method have poor thermal shock resistance. It can be considered to use fused quartz bricks or dense zirconium bricks produced by sintering method. The bricks of the measuring hole and the inspection hole are subjected to long-term erosion by the overflowing flame in the kiln, and are easily burned and cracked. Customized fused zirconium corundum bricks containing 33% Zr02 are commonly used.