Five main quality indicators of refractory

• Refractoriness

Refractory nature in the course, resist high temperature without melting, called refractoriness.

Refractoriness refractory given temperature limit used is an important indicator of assessing the merits of the refractory quality.

• Thermal shock resistance

Refractory resist drastic temperature changes without cracking or peeling ability, called thermal shock resistance. This cyclical nature of the furnace heating and cooling operations is important.

• High-temperature structural strength

    At a high temperature and a certain load is applied to the refractory deformation temperature from the start of the deformation to some extent, the structure is called a high temperature or high strength load softening temperature. It is the ability of the refractory temperature and the load resistance while being deformed under the action of this nature and by the selection of a high temperature furnace under the building material force is important.

• Volume stability at high temperatures

    Refractory material for a long time under high temperature, resulting involume expansion, the expansion is called the residual.

Size refractory residual swelling, reflecting the quality of the high temperature volume stability: the smaller the residual deformation, volume stability, the better; contrary, the worse the stability of the volume, the more likely to cause deformation or damage to the masonry.

• Lag resistance

    Ability to resist the erosion of refractories and slag of molten material in

the course of soot and other damage without being called a slag resistance. Slag resistance is an important indicator of the refractory nature of the work you are, the higher the better ability of anti-slag. Good slag resistance refractory high life.

Special aluminum carbon refractories

Special refractory aluminum carbon and carbon refers to aluminum as raw materials, in most cases, added to other materials, such as SiC, metals Si, Al, etc., bonded together with an organic resin or pitch carbon composite binder special refractories. Broadly speaking, the alumina and carbon as main components are called refractory carbonaceous refractory aluminum. Aluminum carbon refractories their different production processes can be divided into two categories:

do not burn carbon refractories and firing aluminum aluminum carbon refractories.

Aluminum does not burn carbon refractories are bound carbon refractories, because of its antioxidant activity was significantly better than Bricks and excellent anti-corrosion performance system Na2O slag, so widely in the blast furnace, ladle hot metal pretreatment equipment, etc. applications. Aluminum carbon refractories are fired combined-type ceramic refractories, because of its high strength, good resistance to corrosion and thermal shock resistance, and thus a large number of suitable casting sliding gate system with skateboard brick and casting Big Three, namely long nozzle, submerged nozzle and overall stopper rods.

Alumina has a high resistance to acid, basic slag, metal and glass capacity effect solution. It is a high temperature in an oxidizing atmosphere or under a reducing atmosphere used can be a good effect. Carbon and graphite materials have a particularly high thermal conductivity and low coefficient of linear expansion, while a solution having a high temperature with no residue and wettability. So aluminum carbon brick has the following properties.

(1)    aluminum carbon refractories have excellent slag resistance and thermal shock resistance. Compared with magnesium carbon refractories, aluminum carbon refractories have better resistance to alkali TiO2 slag erosion and corrosion capabilities.

(2)    For aluminum baking carbon bricks, because silicon and carbon additives at a high temperature to form silicon carbide, so as to have a double bonding system, i.e., a combination of carbon and ceramic bond, and thus calcined alumina carbon refractory with high mechanical performance, not only act as a conventional continuous casting refractories, and is a functional configuration of the material.

Refractory industry developing trends——Cyanite

Future high-purity refractory materials will be the main and synthetic natural selection and use. Development and utilization of the "three stone" raw materials, namely andalusite, sillimanite, kyanite raw materials, can improve the microstructure and thermal properties LAS refractories.

As the "three stone" at high temperatures into the lower phase mullite and mullite expansion coefficient is small, help to improve the thermal shock resistance of the material. Andalusite in the material can be added with countless subtle diffusion thermal stress becomes void formation, making the stress to be released within the refractory, thus improving the thermal shock resistance. And sillimanite completely mullitization the temperature is higher, will help improve the high-temperature creep resistance. In addition, due to the volume expansion effect produced mullitization also accompanied by high temperature creep favorable. Development of high-quality synthetic refractory raw materials, the amount of developed countries in the use of natural raw materials reduced and the amount of high-purity synthetic raw materials is increasing, the reason is the extensive use of synthetic materials proportion of unshaped refractory materials is increasing, and the extensive use of natural raw clay brick, high alumina brick, zircon brick production is declining.

Therefore, innovation, research and development, education, management and investment, will be the key to maintaining the vitality of future refractory industry and success. Current and future years for Chinese refractories industry, is an experienced structural optimization, corporate restructuring and product structure adjustment period. China's strategy of development should be based on Chinese refractories rich natural resources, based on the development of high-performance synthetic materials and more high-performance, functional products to meet the advanced requirements of high temperature industrial development and a focus on clean steel casting and production. At the same time, you should pay attention to equipment and management, improve product quality refractory materials and the stability and reliability.

Refractory development in China

Ancient, medieval, Renaissance refractories, industrial revolution around the blast furnace, coke oven, stove refractories, refractory materials and new manufacturing processes post-modern manufacturing techniques and refractory major technological advances of modern,

as well as the future of refractories Prospects of development, refractories and high temperature technology accompanied appears roughly originated in the mid-bronze Age. China Eastern Han Dynasty has been made to burn wood and porcelain kiln sager clay refractories.

Early 20th century, the high-purity refractory, high density and ultra-high temperature product direction, while there has been complete without firing, small power consumption monolithic refractories and refractory fibers. Modern technology with the development of atomic energy, space technology, new energy technologies, high temperature, corrosion resistance, thermal shock resistance, excellent performance integrated erosion and other refractories has been applied. There are many factories in China producing refractory products. China is rich in resources, but also because the reasons for this, the major foreign investors came to China also have a go, emerge.

In China's northeast, is a supplier of refractory extremely lush areas, leading to other foreign investors lower their export prices have been questioned, which in 2003 proposed a new product for the Chinese refractories by the EU anti-dumping, limiting the product exports to the EU. 2006 China's raw material resources for the protection of a huge loss on the part of industry produced a relief rebate, thus greatly limiting refractory products exports. But this does not limit the number of foreign brands sold in large part because they have dozens or even hundreds of years of sales experience in production and market share dramatically, they also created the brand in every continent.

Several types and application of ceramic fibers

Lightweight ceramic fiber is a fibrous refractory material, the main chemical ingredient is aluminum silicate, can be classified according to their mineral composition glass fiber and polycrystalline fibers into two categories. Glass fiber is a material from the molten liquid in the cooling flow formed amorphous solid fiber;

polycrystalline fiber and more colloid injection method (or rejection wire method) into fiber, high-temperature calcinations generation.

Types and Uses.
     Ceramic fiber varieties are: ordinary aluminum silicate fiber, high alumina silicate fibers, aluminum silicate fiber (including Cr2O3, ZrO2 or B2O3), polycrystalline alumina fibers and polycrystalline mullite fiber. Form of ceramic fiber products mainly include: ceramic fiber cotton, felt, blanket, modules, paper, cloth, tape, rope, etc.

Ceramic fiber blanket (Fiber Module): use more self-blow, even the melting process is made even thrown Production spun long fibers, the fibers interwoven sided acupuncture can be directly used as a flame hot surface.Widely used in heat insulation petrochemical, metallurgy, electric power and so on.

Ceramic fiber: binder and ceramic fiber additive, after pulping, forming, curing and drying processes are made. Widely used in various heating equipment walls, roof and other parts of the backing, is a heavy refractory.

     Ceramic fiber cloth, tape: mainly used in fire doors, insulated industrial furnace insulation, heat pipes and containers.

     Ceramic fiber rope: mainly used in various industrial furnaces expansion joints, high temperature pipe insulation winding, insulation and other steel junction.

     Ceramic fiber paper: made ​​of ceramic fibers and binders, additives, after pulping, molding, curing and drying processes made, is sealed, an ideal material for insulation. Can be used for a variety of thermal furnace expansion joints, high temperature gaskets and other parts of the insulation.

Also, the ceramic fiber filter and the catalyst can be applied to a support material, packing materials and friction materials, insulating coatings, reinforcing materials.

Analysis of the furnace refractory fiber shedding

The use of coal tar as a trolley furnace heating fuel, did not use the media atomization or purge, often caused by poor atomization flame and combustion endless phenomenon of black smoke and coke burners serious, on the surrounding environment cause great pollution.

Because it is artificial ignition, Yilong refractory fiber board left some gaps around each burner for ignition purposes, the ignition process, coal tar easily leak from the ignition mouth, unpleasant taste, acting on the skin will cause a variety of toxic dermatitis, and long-term inhalation can cause nasal injury, leading to cancer.

Due to the use of coal tar, fuel burning ember of the lower part of the fuel and the combustion flue gas flow with the dust, erosion and attached to the furnace wall, causing cooling the outer surface of the furnace wall refractory fiber compaction, formed on the surface of the furnace wall refractory fiber tension, causing refractory fiber powder and caused chunks off, shortening the life of the furnace.

Sealing mechanism using a knife in the form of letters, the use of positive pressure stove running, forged into the workpiece when the car needs many times

the material, so that the blade moving sands production region accumulation tank seal uneven, resulting in lower blade seal, the seal poor areas appear hot flue gas spills, foam isolation seal groove with a blade or burned, the sealing effect rapidly reduced after a vicious cycle.

 On the part of the car with a small gap between the furnace wall trolley furnace refractory, heat distortion seal groove blade or even affect the normal out of the trolley, and therefore had to knock out the hot stove inserts to improve the car's normal into the furnace, which will result in a flaming furnace trolley serious.