refractory

The part of the clarification that is in contact with the glass is in the same environment as the glass in the melting part, except that this part is usually operated at a much lower temperature. The upper structure of these parts of the maximum temperature is generally about 1399 ~ 1454 ℃, while the maximum temperature of most glass may reach 1399 ℃. There is often greater flexibility in choosing refractory materials for these locations because erosion rates are much lower here. However, the more the liquid glass flows toward the forming end of the furnace, the more the quality of the glass is affected by defects in the refractory material. The main reason for this is that the glass in these areas has a high viscosity and at this lower temperature it is difficult for glass to assimilate solid or gas defects originating from the refractory. In addition, the glass does not have much time to ask to complete the process of assimilation of the above defects. ② fluid hole. ③ bridge walls and side walls. ④ feed through the entrance. ⑤ bottom of the pool. 4 Clarification Department of the upper structure ① Overview. Similarly, this part of the temperature is much lower than the melting part. Clarification of the Ministry of the superstructure environment largely depends on the structure of the lattice wall, that is, the end wall and the melting part of the way separated. When using an open cell wall structure, steam condensation may occur due to the conditions in the melting section. The superstructure refractory material reacts on the surface of its refractory material due to its relatively cool area. In general, erosion is caused mainly by alkali vapor. After completely isolating the atmosphere of the fusing part and the fining part, only a very small amount of vapor escaped from the surface of the glass liquid to erode the refractory material in this area. Borosilicate glass furnace does not comply with this law, where the surface of the glass continuously release volatile sodium borate, even in the material so. In general, the best practice for borosilicate glass furnaces is the use of zirconium-based refractory materials or the use of silica-based refractory materials.

Refractory clay is a monolithic refractory material used to prepare a slurry of powdered refractory materials and binders. It is mainly used for masonry brick masonry joints and as a coating material. As a puzzle material or paint use, require the same material and refractory bricks.

Refractory soil, also known as clay refractory soil, a set of furnace with a soil, is a weak acid refractory material, and its good thermal stability, suitable for masonry stove, a variety of boiler lining, and flue, smoke chamber Wait.

Refractory cement is a material used in the manufacture of refractory castables, with a refractory resistance of not less than 1580 ° C. According to the composition of different can be divided into aluminate cement, calcium aluminate, calcium magnesium aluminate and dolomite. When using purely fire-resistant cement, then a lot of cracks will occur after high temperature, it is necessary to pay attention.

Refractory cement and refractory refractory are a kind of fire-resistant cement refractory at 1300 degrees, he has a high strength after condensation, the label can reach 625, mainly mixed with the bauxite aggregate equipment used in refractory high Refractory concrete, fire-resistant refractory soil at 1000 degrees, there is no strength after the coagulation, only play a certain bonding effect, refractory soil is generally used for brick masonry or paste wall furnace.

If the fire-resistant cement and refractory soil are used in combination, then the value of refractory cement will be greatly discounted, equivalent to the fire-resistant cement and loess mixed together as one reuse, refractory cement coagulation strength and labeling will be much lower.

Refractory selection principles Refractory selection before you need to first understand the following factors: ① the life of the pool furnace; ② glass quality requirements; ③ production capacity, that is, the melting rate and melting temperature selection; ④ insulation, in order to save fuel in the Which parts to take insulation; ⑤ economy, that is, how much investment. In the selection of refractory materials to hijack the use of requirements to ensure the economy of the pool furnace, easy to manufacture. (1) Ensure that all kinds of refractory materials used for building glass pool furnaces should meet the following basic requirements: ①High softening and melting temperature, generally not less than 1580 ℃. ② sufficient mechanical strength, can resist the impact, friction, high temperature high-speed flame, dust erosion and other mechanical effects. ③ high temperature structural strength, operating temperature can withstand long-term mechanical load. ④ melting compound ingredients, molten glass and gaseous substances erosion resistance strong. ⑤ the pollution of the glass should be small. ⑥ hot and cold-resistant thermal performance (thermal shock) is good. ⑦ high temperature volume stability, residual contraction or expansion of small. ⑧ heat capacity, thermal expansion, thermal conductivity and other thermal properties to meet the requirements. ⑨ shape regular, accurate size. ⑩ other requirements according to the conditions of use (such as the electrical properties of the electrode brick to meet the requirements). (2) to ensure the economy of the pool furnace Refractories should be taken from the actual departure, the full study of the entire furnace furnace refractory life balance of various parts, with less investment to achieve greater economic results. Fully guarantee the economy of the glass pool furnace and the balance of the life of the pool furnace. (3) easy to manufacture and choose Refractory, should be taken into account the use and manufacture of both. Refractory brick, the standardization of the size is conducive to the development of refractories production, easy to achieve the finalization of the glass pool furnace is conducive to construction and maintenance. S & P brick usually cost 30% to 50% less than shaped brick. Indigenous glass furnace should be given priority to the use of standardized refractory brick. 5.3 Furnace operation and maintenance Reasonable furnace operation system is to extend the useful life of the furnace and access to quality products, an important guarantee that the operation of the furnace must be strictly in accordance with the provisions of process documents

Refractory materials are the main building blocks of glass melting furnaces and have a decisive influence on the quality of glass, energy consumption and even the cost of the product. The development of glass melting technology depends largely on the progress of refractories manufacturing technology and quality improvement. Glass Furnace Furnace Structure For large float lines, the glass kiln is usually constructed of L-shaped hanging wall (usually using silica bricks), melting section (fused glass in direct contact with glass, upper used (Usually using silica bricks), the cooling section including the ototoxic tank (where the corundum material is used in direct contact with the liquid glass, and silica brick or corundum is used where it is not in contact with the liquid glass), annealing Kiln, regenerator (made of clay, high aluminum, direct combination of magnesia-chrome brick) and other parts. Glass furnace main parts of the conditions of use and refractory choice
Glass melting furnace and cooling Department of the top (including the arch angle), the site is often at 1600 ℃ operating temperature, the use of refractory material in this area is subject to high temperature, load but also by the alkali steam and compound Therefore, the material used for the top must have high refractoriness, high load softening temperature and good creep resistance, and the thermal conductivity is small, the erosion of high temperature does not pollute the glass liquid, the bulk density is small, High temperature strength and other characteristics. The high-quality high-purity silica brick with just the above characteristics: 1, the load temperature close to the refractory; 2, high temperature stability, high strength; 3, due to the main component of SiO2, content> 96%, the same as the main components of glass , So erosion under high temperature basically does not pollute the glass liquid; 4, the price is cheap. Therefore, at present, in the top of large-scale glass, pure high-quality high-purity silica bricks become the glass of choice for manufacturers. The chemical attack caused by high temperature chemical reaction between fly ash, alkali vapor and refractory materials, as well as the change of the crystal form and the change of the structure due to temperature and phase migration are the main reasons for the damage of the top tile. The results show that the high-quality glass kiln silica brick is used in the top of 碹 roof, and the alteration process at high temperature is basically phase transformation and impurity migration. The chemical attack and melting effect are extremely slight. As a result of phase change and self-purification, the working belt gradually changes its performance and its high temperature performance is improved.

Refractory raw materials processing is to enter the factory of various shapes and sizes of refractory raw materials (including raw ore and clinker) into the required size, and remove impurities mixed with refractory raw materials for the preparation of brick use. Refractory raw material processing include: selection of refractory raw materials, crushing, grinding, fine grinding and screening.
The selection of raw materials into the plant
The selection of refractory raw materials into the plant there are two main purposes: (1) selected mixed in the raw materials in the debris, under burning material, not burning fuel and tumor blocks, etc .; (2) According to the appearance of refractory raw materials Features are stacked for ease of management and use.
Broken smashing purposes
The mechanical method (or other methods) exerting external force on the large refractory raw materials so as to fragment them into small pieces or fine powders is called raw material crushing and pulverizing.
Usually two or three broken crushed. That broken – broken pieces of material from 250-300mm broken 40-50mm;
Crush – Material block size from 40-50mm crushed to 4-5mm;
Fine grinding – finely ground material size from 4-5mm to less than 0.088mm.
The purpose of crushing is to prepare massive refractory raw materials into pellets and fine powders with a certain granular composition so that powders of different compositions are prepared and mixed uniformly; the specific surface area of ​​the raw materials is increased and the physicochemical reaction speed is increased.
Impact broken broken factors

Insulation brick seven major features: Insulation, insulation: effectively reduce energy consumption. Fire: A national standard or not. Clean, environmentally friendly: will not cause secondary air pollution. Light weight: only about 1.4 kg

1. Porosity The apparent porosity reflects the density of the refractory material, ie the percentage of apparent pore volume in the brick to the total volume of the brick.
Bulk density is the mass of the total volume of refractory unit volume, including pores.
3. True density Refractory unit volume does not include the stomatal volume of the quality.
Thermal properties

In the glass industry, the quality of refractory materials is of great significance for improving the quality of glass products, saving fuel, prolonging the life of melting furnace and reducing the production cost of glass. Refractory materials are the material basis of glass furnaces and have a great impact on the overall kiln efficiency. They must be properly selected. Different parts of the pool kiln performance requirements of different refractory materials are also different. The basic requirements for refractories for glass melting furnaces are generally as follows. Sufficient performance is required.  such as high temperature performance, chemical stability, hot and cold emergency stability, volume stability and mechanical strength. Pollution or minimal pollution Maximize service life No contact between refractory materials of different materials built up at high temperatures Reactivity and size Exactly as small as possible Heat and radiation losses  Vulnerable parts made of high quality materials  Other parts used General materials. Achieve “a reasonable package  kiln age synchronization
Melting Department in contact with the glass of the site
Most glass-contact refractory materials are damaged by liquid-phase erosion dominated by diffusion. Soda lime glass has a liquid temperature of up to about 1500 ° C. The glass temperature of other glasses than soda lime glass may be higher or lower depending on the required viscosity characteristics of the glass and the composition of the glass. The most important property of refractory material for all glass-contacting parts is resistance to corrosion. The two properties of refractory interface stability and the tendency to produce stones are almost equally important. Interfacial stability means that the refractory material is partially eroded  However, the surface of the refractory material is still intact and will not fall off and the glass will be defective.

Alumina content of more than 48% of a neutral refractory. By the bauxite or other high alumina content of the material by molding and calcined. High thermal stability, refractoriness above 1770 ℃. Better slag resistance. For masonry EAF, glass furnace, cement rotary kiln and other fabrics.
High load soft, low creep high alumina brick is a high-grade refractory made of premium alumina, fused corundum, fused mullite as the main material. The product has a high temperature creep small, strong corrosion resistance, thermal shock resistance and good long-term, suitable for large and medium-sized stove, it is China’s new hot-blast stove required high-quality, high-grade imported refractory domestic pioneers Next The road to success, has been included in the national “Spark Program” project.
a, refractoriness
High alumina brick refractory than clay brick and half-brick refractory high, reaching 1750 ~ 1790 ℃, attributed to high-grade refractory materials.
b, load softening temperature
Because the high alumina content of Al2O3, less impurities, the formation of friable vitreous less, so the load softening temperature higher than the clay brick, but because of the formation of mullite mesh structure, so the load softening temperature is still no high silica brick.
c, slag resistance
Alumina Al2O3 brick more, close to the neutral refractory material, can resist the corrosion of acid and alkaline slag, because of the SiO2, so the ability to resist alkaline residue than acid residue ability weaker.
The use of high alumina bricks
Mainly used for masonry blast furnace, hot stove, electric stove roof, blast furnace, reflector furnace, rotary kiln lining. In addition, high alumina bricks are also widely used as hearth heat regenerative lattice bricks, plugs used in casting systems, nozzle bricks and so on. However, the price of high-alumina brick clay brick is high, so the clay brick to meet the requirements of the local do not have to use high-alumina brick.

Zirconium-containing corundum brick Zirconia, zircon as raw material to produce corundum brick. Zirconia series products, zircon series products, zirconium mullite and zirconium corundum series of products belong to such products. According to the different production processes, zirconium-containing corundum brick is divided into sintered products, fused bricks and non-burning products. Zirconia-containing corundum brick has the characteristics of high melting point, low thermal conductivity and good chemical stability, and has good corrosion resistance to molten glass in particular.

The Zr-O system has several phases of oxygen in zirconium oxide and a non-stoichiometric oxide of the same melt. The stable compound of zirconium and oxygen is dioxide ZrO2. Zirconium dioxide has an ion radius ratio of 0.66, which is close to the limit of crystal coordination numbers 3 and 6. The zirconium cation is larger in size (0.082 nm) .In order to achieve the 8 coordination, oxygen ions are not as close as possible in the crystal lattice. Therefore, ZrO2 exhibits anomalous coordination. When its coordination number is equal to 7, one of the oxygen atoms occupies the space between two nodes of the AB crystal lattice. A lattice coordination and B lattice 4 coordination, High temperature by ions in the lattice node thermal motion occurs longer bond length is due to oxygen ions from the unit space transition to the A or B position knot preclude. Anion vacancies at the same time to achieve the 8 coordination.

The properties of Zr-bearing corundum bricks depend on the nature of ZrO2. Density and Stabilization The melting point of zirconia is 2677 ℃ and the temperature is 2500 ℃. The bulk density fluctuates 4.5 ~ 5.5g / cm3 due to the purity of the raw materials and the manufacturing method. The bulk density of compact zirconium corundum brick can reach 5.75g / cm3. Sintered zirconium corundum brick and liquid glass can not afford chemical reaction. Caustic solutions, carbonate solutions and acids (except concentrated H2SO4 and HF) do not react chemically with zirconia. ZrO2 has high structural strength and as a lining of the hot surface has the ability to work at 2200 ~ 2450 ℃ temperature.

Zirconia corundum brick high mechanical strength, and strength has been maintained to 1300 ~ 1500 ℃. The thermal conductivity of ZrO2 is much lower than the thermal conductivity of all other oxide materials. The use of ZrO2 this feature can be made of high temperature insulation layer.

In the shipment of refractory bricks, should pay special attention to the occurrence of bumps, so as to avoid cracks and corner, affecting the quality of refractory bricks. So the handling must be refractory bricks and rice bandaged, in the handling process should be lightly put.

In order to facilitate the use, to avoid misuse, storage should be in accordance with the variety of firebrick, shape, different models were stacked. Each kind of refractory bricks should be in accordance with the actual needs of the necessary reserve. Storage should be dry, so as not to reduce the quality of refractory brick water.

After the refractory brick into the factory, should carry out verification and selection work, will not grid (if crack and corner) out. Validation of the important inspection of refractory bricks chemical composition, type, shape, whether the degree of compliance requirements, such as for refractoriness, resistance to rapid cooling, pressure and other experiments on the more difficult. On the proportion of refractory requirements of the error is not greater than 3 mm, such as the error is too large, will bring the puzzle to the puzzle, puzzle quality is also difficult to guarantee.

The quality of refractory bricks is one of the key conditions to determine whether the kiln can operate safely all the year round. So pay attention to the handling of refractory bricks, good fire brick storage and verification work can not be ignored.

The refractory bricks can fill the pores between the pig iron particles while forming a gel with the liquefied product, with the alkaline material magnesium oxide lining to form a gel. In the pig iron-based concrete, mortar and refractory castables, mixed with the amount of refractory bricks, refractory steel and castables should be made by the laboratory construction tacit ratio. In strict accordance with the tacit than construction. In the agitation of refractory steel, the refractory bricks should be added to the stirrer after the aggregate is put on. Refractory bricks in the composition process, due to the process of transition due to the effect of cortical tension, constitute non-crystalline amorphous spherical particles, and the cortex is quite clean, and some are a number of ball particles adhere to an example of the comon The It is a very much deeper than the skin layer, the activity is very high volcanic ash objects. Mixed with refractory bricks, fine spherical body can play a lubricating effect.