Refractory materials for glass melting furnaces
The construction of refractory materials for glass melting furnaces is an important basis for whether the furnace can reach the expected service life or extend the service life. At the beginning of the purchase period of refractory materials, the performance and quality of the materials must meet the requirements of national standards or design requirements, and the construction should also comply with relevant national standards or industry standards. The following are the requirements and precautions for the construction of refractory materials for glass melting furnaces:
Requirements for the construction of refractory materials for glass melting furnaces
① The masonry of glass melting furnaces must be constructed according to the design, and the refractory materials used must comply with the design requirements and relevant national or industry quality standards.
② The masonry construction of refractory materials for melting furnaces should strive for continuous operation and should not be stopped for too long due to material supply. Therefore, refractory material companies are required to strictly supply goods according to the date specified in the contract.
③ Requirements for construction in different seasons
Winter construction: Ensure that the temperature of the masonry is not lower than +5℃, the masonry mud and castables need to be stirred and blended with hot water, the mud needs to be kept above +10℃, and chemical coagulants and antifreeze agents should not be added.
Construction in rainy season: masonry sites, masonry materials and masonry must be protected from rain, and masonry must not be exposed to rain or soaked by water.
④ During the baking process of the melting furnace, some bricks still need to be hot-laid, such as plugging expansion joints, caulking joints, and covering special joints, etc., which should be carefully operated according to the procedures.
Matters needing attention in the masonry process of refractory materials in glass melting furnaces
01
Requirements for masonry brick joints
According to different parts and use requirements, the requirements for the size of masonry brick joints are divided into the following 4 categories.
Special masonry: brick joints do not exceed 0.5mm.
Class I masonry: brick joints do not exceed 1mm.
Class II masonry: brick joints do not exceed 2mm.
Class III masonry: brick joints do not exceed 3mm.
02
Masonry methods
Dry masonry and wet masonry are used according to different parts and use requirements
Dry masonry parts: clay bricks at the bottom of the melting furnace, pool wall bricks, runner pool bottom, pool wall and top cover, pool wall gap bricks, lattice body, pool bottom insulation support brick stacks and neck partition walls, etc. Other parts must be wet masonry with mud.
03
Requirements for masonry mud
① Use matching masonry mud for refractory materials of different materials, and do not mix or misuse them.
② Pre-masonry should be done before masonry to determine the bonding time, viscosity and water consumption of different muds.
③ Use different utensils to mix different muds, and do not mix them. If necessary, they should be cleaned before use.
④ Clean water should be used to mix mud, with accurate water consumption and uniform mixing (mud mixer is required) and it should be used as soon as it is mixed. Water or dry powder should not be added to the prepared hydraulic and air-hardening muds at will, and the initial setting mud should not be used again.
⑤ Mud that has expired should not be used again.
04
Requirements for masonry expansion joints
① Expansion joints must be set according to design requirements, and the error between the expansion joint size and the design at any part should not be greater than 2mm.
② There should be no debris in the expansion joint (including filled wooden boards, cardboard, straw ropes, etc.).
③ Expansion joints should avoid stress-bearing parts and steel structures, and expansion joints at the bottom of the kiln should be sealed with tape.
④ The form of expansion joints should be staggered structures, and the design of expansion joints that need to be blocked should be convenient for blocking.
⑤ Masonry that contacts expansion joints should be built with refractory materials, not insulation materials.
05
Insulation of melting furnace
① The insulation layer of the melting furnace shall not wrap the steel structure of the melting furnace, and the ventilation of the steel structure shall be guaranteed.
② The expansion joints of the vault, bottom, wall, and wall of the melting furnace shall not be insulated, and the thermocouple measuring holes and other observation holes shall not be insulated.
③ The melting pool wall 200~400mm below the liquid surface shall not be insulated.
06
Requirements for masonry of melting furnace arches
① The mud joints of the arch bricks shall be built according to the design requirements. If they do not meet the requirements, they must be reworked and rebuilt. It is strictly forbidden to move the arch tire to change the brick joints, and it is also forbidden to build by increasing the mud joints. Bricks can be processed if necessary.
② All arch bricks must fit tightly with the arch formwork to ensure the conformity. The arch bricks are strictly prohibited from being inverted. The length of the cracked bricks at the end of the arch shall not be less than 150mm.
③ The middle lock bricks of the arch are required to be evenly placed with mud, and then the last row of lock bricks are locked at the same time. After the arch is built, grouting is performed on the arch.
07
Requirements for masonry with multiple materials
For walls built with multiple refractory materials, except for biting according to special design requirements, the walls are bitten once every 5 to 8 rows of bricks. When biting, the inner bricks are bitten to the outside, and the insulation materials cannot be used as biting materials.
08
Requirements for mud in brick joints
The mud in the brick joints of masonry built with mud in the melting furnace should be full. The mud in the brick joints must be bonded to the brick surface. The wall surface is required to be grouted with mud of the same material, and the excess mud on the masonry surface should be scraped off in time.
09
Requirements for reprocessing of refractory materials
Cast refractory materials should be cut and ground according to design requirements, and the brick surface in contact with glass liquid should be sanded. The surface of sintered materials in contact with glass liquid and flame should not be processed or damaged. The method of selecting bricks and grading can be adopted to meet the requirements for the external dimensions of bricks.
10
Record masonry numbers
The masonry structures of the feeding port crown, the small furnace blast port crown, the small furnace crown, the wall and bottom, the neck crown and cast refractory materials should be masonry and numbered.
11
When masonry of the melting furnace, the following common problems should be avoided as much as possible
Wall dislocation; double seams; straight seams; inverted crown bricks; crown bottom opening; crown brick draw; crown bricks not in place.
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