Fireclay refractory products are weakly acidic refractory products. As the content of SiO2 increases, its acidity increases, and it has certain corrosion resistance to acid, but poor resistance to alkaline corrosion. Therefore, fireclay refractory products are suitable as refractory materials for acid kilns. Large-scale fireclay refractory bricks for glass kilns refer to fireclay refractory bricks with a unit weight of not less than 50kg for masonry glass kilns.
The Properties and Application of Fireclay Bricks
Clay refractory bricks are refractory products produced from refractory clay as raw materials and are widely used in industry. The thermal vibration resistance of clay bricks is good, and the fluctuation range is large, generally more than 10 times (1100℃ water cooling). This is related to the fact that the linear expansion coefficient of the clay product is not too large, there is no polycrystalline transformation phenomenon, and it has an obvious granular structure. Therefore, clay bricks are often used as large bricks at the bottom of the pool in glass kilns.
Product Characteristics of Large Fireclay Bricks for Glass Kiln
- Low rate of change of re-burning line,
- Dense structure,
- Good thermal shock resistance,
- Resistant to rapid cold and heat,
- high purity,
- High-temperature mechanical strength,
- Low porosity,
- Low creep.
The Main Application of Large Fireclay Bricks for Glass Kiln
It is especially suitable for building the bottom and wall of the glass melting furnace.
Production Technology and Advantages of Large Fireclay Bricks for Glass Kiln
As the large clay bricks used in glass kilns are generally large, the unit weight is required to be more than 50kg, and some even weigh 400-500kg. It is not advisable to use the ordinary press method or ramming method to form, generally adopt the casting method.
The main points of the production process for the production of large clay bricks for float glass tank bottom by vibrating casting molding method are as follows.
- Clay clinker, fine mullite powder, ultrafine oxide powder, and hardener are used to form self-hardening mud.
- The brick-making mud material is mixed to have both thixotropy (vibration castable can be used for molding) and self-hardening.
- After being formed, the mud can be de-moulded after a certain period of time has passed.
In order to meet the requirements of the molding process, a small amount of degelling agent and a small amount of late-acting coagulant are appropriately added to the ingredients. The addition of degelling agent can not only reduce the amount of water used from 10% to 13% to 5.5% to 6.5% but also obtain a uniform structure. Adding a delayed coagulant can make the body and outside of the blank solidify simultaneously, thereby shortening the demolding time.
Large-scale clay bricks formed by vibratory casting, due to the effect of surface tension during the vibration process, most of the gas that cannot be removed from the mud is present in a spherical shape, forming closed pores. Therefore, the air permeability of the brick is low, which can effectively hinder the diffusion of oxygen through the refractory wall. Therefore, brick cracking caused by the volume expansion caused by the oxidation of metal tin to tin oxide can be avoided. Moreover, due to the low air permeability of the bricks, the hydrogen diffusion is also low, thereby avoiding glass defects caused by bubbles at the bottom of the tin bath, thereby increasing the yield of glass.
The large bricks at the bottom of the clay pool are formed by vibration pouring and special refractory casting materials. It is far superior to products produced by the traditional mud pouring process molding and tamping process in terms of resistance to glass erosion and alkali steam erosion.
The Allowable Deviation of the Size of Large Fireclay Refractory Bricks for Glass Kiln
Because large clay refractory bricks for glass kilns are clay refractory bricks with a unit weight of not less than 50kg for masonry glass kilns. China Metallurgical Standard (YB/T 5108-1993) stipulates the physical and chemical indexes, allowable size deviation, and appearance of large clay refractory bricks for glass kilns.
This standard also makes the following provisions for the section cracking of bricks:
(1) The cross-section of the brick is cracked:
- 1) For bricks with the length ≤ 400 mm, the length shall not exceed 40mm when the spall width is 0.26～0.50mm; when the spall width is 0.51～1mm, the length shall not exceed 25mm.
- 2) For bricks with the length > 400 mm, when the spall width is 0.26～0.50mm, the length is not more than 80mm; when the spall width is 0.51～1mm, the length is not more than 50mm.
(2) For cracks with a spall width of less than 0.25mm, the length is not limited.
(3) There shall be no pores or cracks larger than 1mm on the section.
Buy High-Quality Large Fireclay Bricks for Glass Kilns
To purchase high-quality large clay bricks for glass kilns, refractory brick manufacturers are preferred. Because it is purchased directly from the manufacturer, not only the quality of the large clay bricks is guaranteed, but also the cost can be saved. Large-scale refractory brick manufacturers are also equipped with comprehensive customer service, which can guarantee the after-sales service of their products. As a refractory material manufacturer, Rongsheng refractory material manufacturer not only has rich experience in the production and sales of refractory materials but also can provide customers with customized refractory products and refractory lining materials solutions. If you have the need to buy refractory bricks or to obtain refractory lining material solutions, please contact us. We will provide you with services according to your specific needs.