Refractory Materials @refractorybrick - Tumblr Blog

What Installation Steps Does Ceramic fiber module have ?

The installation steps of ceramic fiber module:

Scrap rust: before construction, steel structure party need scrap rust to the furnace wall copper plate, in order to meet the welding requirements.

Wiring: according to the design drawings as shown in the ceramic fiber module arrangement, pay off on the wall board, mark the welding points of anchor bolt arrangement.

Welding bolts: according to the design, welding the corresponding length of bolt on the furnace wall board according to the requirements of welding, when welding, should take protective measures to the bolt thread part, shall not splash down welding slag to the part of the bolt screw thread, and ensure the welding quality.

Smear high-temperature and anticorrosive coating layer: according to the provisions of the design drawings, on the wall plates and bolts’ root evenly welds high temperature anticorrosive coating layer, the coating thickness according to 3 kg/m2. When brushing, should take the protection measures to bolt thread part, must not splash down coating to the part of the bolt screw thread.

Tile carpet installation: laid the first layer of fiber blanket, and then laid the second fiber blanket, a stagger volume of joints should be no less than 100 mm. For the convenience of construction, furnace roof tile need make rapid card to make temporary fixed.

The installation of module

The installation of compensate carpet

Lining repair: finish the whole lining installed, from top to bottom for renovation.

What Are The advantages of Fire Clay Brick ?

Fire Clay brick is used in construction of artificial small piece of material, is one of the world’s oldest building materials. With clay (such as shale, coal gangue powder) as the main raw material, pass through sludge processing, molding, drying and roasting completed. The main raw material of fire clay brick is nature or sandy clay, its main chemical composition is SiO2, Al2O3, Fe2O3 and crystallization water, because of the different geological formation conditions, may also contain a small amount of alkali metal and alkaline earth metal oxides. The production technology of fire clay brick mainly includes soil, mud, blocking, drying, roasting, etc.

The advantages of fire clay brick:

Fire clay brick shows weak acid under high temperature, alkaline slag erosion resistance is a bit poor, but enhanced with Al2O3 content increase, and the thermal stability than silica brick, magnesia brick as well.

The blast furnace fire clay brick of quality qualification goes through drying treatment, vacuum impregnation phosphate, secondary low temperature firing of phosphate impregnation products, can be used for laying on blast furnace lining.

Fire clay brick use local materials, cheap price, durable, and fire prevention, heat insulation, sound insulation and absorption of moisture, widely used in civil instruction engineering, waste brick bat also can make concrete aggregate.

Fly ash fire clay brick with fly ash as main raw material, mixed with coal gangue powder or clay and cementation material, going through the ingredients, molding, drying and calcination completed, can make full use of industrial waste residue, save fuel.

What requirements should Refractory Materials meet?

Refractory materials used for all kinds of high temperature equipment, it is the high temperature condition of the physical and chemical erosion and mechanical damage, so the performance of refractory materials shall meet the following requirements:

High refractoriness. Modern metallurgical furnace and other industrial kiln‘s heating temperature are generally between 1000 ~ 1800 ℃. Refractory material should have no easy to melt performance under the action of high temperature.

High temperature structural strength is large. Refractory materials should not only have high melting temperature, but also should not happen softening deformation and collapse under the stove masonry load or other mechanical shock.

Thermal stability is good. Metallurgical furnace and other industrial kiln are in operation, due to temperature shock caused by uneven temperature of each part of refractory material, masonry internal stress and make the material fissile and peeling. Therefore, refractory materials should have the ability to resist the damage.

Slag resistance ability is strong. Refractory material in use process, often by high temperature furnace slag, metal and chemical erosion of furnace dust. Therefore, must have the ability to resist erosion of refractory material.

High temperature volume is stable. Refractory materials at high temperature for a long time use, bricky system internal can produce volume shrinkage or expansion, causes the damage of refractory masonry.

The energy saving effect of ceramic fiber blanket

Ceramic Fiber Blanket is the clay clinker of high purity, alumina powder, silica powder and other raw materials melting in high temperature furnace, forming fluid. Fiber cotton can be further processed into fiber blanket, board, paper, cloth, rope and other products. Turn out to be an efficient heat insulation material, with the characteristics of light weight, high strength, oxidation resistance, low thermal conductivity, good flexibility, corrosion resistant, small heat capacity and sound insulation, etc.

Ceramic fiber blanket made from ceramic fiber as the raw material, in recent years become each big kiln dedicated furnace lining materials, because of its simplicity and easy construction, and heat insulation effect is better, become a required insulation material of kiln company. The adiabatic temperature can reach more than 1600 degrees, greatly satisfy the needs of the user.

Energy shortage, various cost increase, are the necessity of industrialization process, has the construction application of the energy-saving insulation materials, for the enterprise, it is the top priority in development, ceramic fiber blanket improves the conservation of thermal efficiency, but for some special kilns, due to the particularity of chemicals, may temporarily can’t use ceramic fiber blanket as insulation materials, Therefore, the development and application of ceramic fiber blanket was further improved

The Use Nature of Refractory Materials

In use process of refractory material, due to a variety of differences of environment, a variety of requirements are proposed on the performance of products, whether to meet the requirements of performance indicators, become the main measure standard of the quality of refractory products, and also prolong its service life, improve the important basis of use value.

Refractoriness

Refractoriness is refractory material resist to high temperature function rather than melting performance, its meaning of refractoriness and melting point are different, melting point is refers to the crystalline phase and liquid phase of pure substance is in equilibrium temperature. And general refractory material is multiphase solid mixture composed of a variety of mineral, has no uniform melting point, but began to produce liquid phase under certain temperature, with temperature rising, the liquid phase ratio increases continuously, to a fixed temperature, solid phase can all melt for the liquid phase. Between the two fixed temperature range, both liquid phase and solid phase exist at the same time.

The chemical composition, mineral composition and its distribution of refractory products are the most basic factors to influence the refractoriness. Impurity elements with strong solvent effect, will seriously reduce the refractoriness of products. Uneven distribution of composition that cannot form an ideal high melting point mineral, will lead to lower refractoriness products, so damage the using performance of products, but the refractoriness of products doesn’t mean its use temperature, because refractory material in use, processes through high temperature function at the same time, often with the solvent effect of load and external things and so on. Actually allowable working temperature is much lower than refractoriness, but, after all, the refractoriness index is one of the important reference frame to select reasonably refractory material.

Refractoriness under load

The refractoriness under load of refractory material, also known as the high temperature load deformation temperature, defined as refractory products under persistent overheating conditions, bear deformation temperature under constant load. It said the refractory products at the same time resist the ability of high temperature and load effect.

Linear change on reheating

Linear change on reheating, also known as residual linear change, refers to after the refractory material heated to high temperature, happens the irreversible changes of its length. The specific definition is refractory products sample heated to the specified temperature, heat preservation time, after cooling to room temperature, the length produce residual expansion or contraction.

Thermal shock resistance

Refractory material in use process, the environment temperature change is inevitable.

The production process of Fused Cast AZS Block

Fused Cast AZS Block concrete production process is as follows:

Formulated fused zirconium corundum material

The excellent performance of high purity fused zirconium corundum material, weighing mixed together, make the performance of the raw materials are fully used. material, weighing mixed together, make the performance of the raw materials are fully used.

melting fused zirconium corundum

Will cooperate with fused zircon corundum material add to the automatic control of electric arc furnace, melting at the best possible conditions. With single phase or three phase arc furnace molten melt temperature should be moderate, the batch of low temperature will not be made highly uniform melt, are apt to form porous body castings, make the fused cast products pores and cracks, contract also increases accordingly, make the products form a larger shrinkage cavity.

Pouring

The molten material specially designed injection mold products. Fused cast made dense structure and use of the good performance of fused brick. With appropriate hot melt casting, casting out of the shrinkage cavity concentration of zirconium corundum brick, the dense zone thickness increases, the density of the products also increased. But when overheating degree is high, although the melt density is increased, but the products forming cracks and large shrinkage.

Annealing

After casting a good brick and to slow cooling, make zirconium corundum block made of crystal growth and form the best structure.

The surface processing

Using precision machining equipment to make products fused cast AZS block processing into comply with the design requirements of accurate size. Mechanical processing can improve the quality of fused brick and prolong its service life.

Inspection

Each piece of fused cast AZS block is strict visual inspection shall be carried out in accordance with the contract standard.

The physical and chemical analysis

Control project to the requirement of the contract, the physical and chemical analysis was carried out on the fused brick.

The Advantages of Chrome Corundum Brick

Chrome corundum brick is alumina – chrome oxide as the main raw material production of high-performance, has the characteristics of high refractoriness, great strength, good thermal shock stability, strong ability to resist erosion, in use, has the performances of scouring resistance, wear resistance, resistance to spalling structure, has obtained the good effect in metallurgy, glass, carbon black, the petrochemical industry. Chrome corundum brick using raw material is by the ratio of alumina and chromium oxide according to certain proportion, go through high temperature melting synthesis of a solid solution. Use special refractory materials production technology to make refractory brick, can improve and enhance internal quality of the products, improve the high temperature performance of products.

Refractory properties of chrome corundum brick

Add Cr2O3 to high purity corundum material, no matter how much the amount is, not only will not reduce the fire performance of materials, instead, can make fire performance of the material fire performance improved.

The strength of chrome corundum brick

The room temperature compressive strength of high purity corundum brick is 70 ~ 100 MPa commonly, the room temperature compressive strength of high performance chrome corundum brick is generally larger 150 MPa, the intensity is significantly higher than the corundum brick.This is because the products in the process of burning, between particles and fines powder, fines powder and fines powder formed Al2O3 – Cr2O3 solid solution, calcium solid solution connect particles to fines powder together, make the strength of the material greatly increased.

Thermal shock resistance

Add Cr2O3 to corundum, when the content of Cr2O3 is 10% ~ 66%, the thermal shock resistance of material decreased with increasing content of Cr2O3, namely the low content of Cr2O3 of chrome corundum brick, the thermal shock stability is better than Cr2O3 high content of chrome corundum brick. The Cr2O3 content of high-performance chrome corundum brick is around 12% ~ 20%, improve more stability than the corundum brick.

Slag erosion resistance ability

Cr2O3 or containing Cr2O3 of refractory material has the good resistance to slag, non-ferrous metallurgical slag, coal gasification furnace, oil gas furnace slag and all kinds of glass melt dissolution ability. Cr2O3 melt or Cr2O3 reaction with slag generated liquid viscosity is larger than other low melt viscosity, prevents slag brick along the capillary pores to permeate inside

What are the unique advantages of Sillimanite Brick?

Sillimanite brick is refractory brick made of sillimanite minerals. Commonly using high temperature burning method and mud casting method to product.

Sillimanite brick has five big advantage of using:

The application of non-ferrous metal smelting industry

Use silicon carbid, high temperature resistance, big strength, good heat conduction performance, impact resistance, high-temperature indirect heating material, such as strong retort furnace. Distillation furnace tray, aluminium electrolyzer, copper melting furnace lining, furnace zinc powder with arc plate, the thermocouple protection tube, etc.

The application of iron and steel industry

The use of silicon carbide corrosion resistance. Thermal shock resistance to wear and tear. Good characteristics of thermal conductivity, for large blast furnace lining to improve the service life.

The application of metallurgical mineral processing industry

Silicon carbide hardness is second only to diamond, strong wear resistance, is wear-resisting pipe, the impeller, pump room, cyclone, ore bucket lined with ideal material, its wear resistance is 5 to 20 times than the service life of cast iron,rubber, is one of the aviation flight track ideal material.

The application of building materials ceramic, grinding wheel industry

Using the coefficient of thermal conductivity.The characteristics of thermal radiation, high strength, manufacturing sheet kiln furniture, not only can reduce the capacity of kiln furniture, also improves the loading capacity of the kiln and the product quality, shorten the production cycle, is the ideal indirect materials of ceramic glaze baking sintering.

The application of energy saving

With good thermal conductivity and thermal stability, heat exchanger, burnup decreased by 20%, saving fuel by 35%

The function of Refractory Materials

Refractoriness refers to refractory cone sample in which there are no load cases, resistance to high temperature function and not soften the Celsius temperature. Refractory materials is not less than 1580 ℃ refractoriness of inorganic non-metallic materials. But just to define the refractoriness cannot fully describe the refractory materials, 1580 ℃ is not absolute. Now defined as any physical and chemical properties to allow its use in high temperature environment is called refractory material. Refractory material is widely used in metallurgy, chemical industry, petroleum, machinery manufacturing, silicate, motivation and other industrial area, etc. The dosage in metallurgy industry is the biggest, accounts for 50% ~ 60% of total output.

Although the definition of national regulation is different, for example, the international organization for standardization (ISO) in the official publication of international standard, “refractory material, the refractoriness is at least 1500 ℃ of nonmetallic materials or products (but do not rule out that contain a certain proportion of metal)”, but the basic concept is the same, namely the refractory material is the structure material used for high temperature furnace, furnace thermal equipment, as well as high temperature containers and components of materials used in industry, and can withstand the corresponding physical and chemical change and mechanical action.

According to the refractoriness, can be divided into ordinary refractory products (1580 ~ 1770 ℃), high-grade refractory products (1770 ~ 1770 ℃) and super refractory products (above 2000 ℃).

In metallurgy, silicate, chemical, power, petroleum, machinery manufacturing industry, refractory material is used widely. Metallurgical industry of refractory consumption accounted for about 50 ~ 60% of the total refractory.

What is Silica Brick?

Firstly, the most basic is that the nature of silica brick belongs to acidity.

The true density of silica brick is the smaller, the lime change is the more complete, in the process of the oven, generated residual expansion is the smaller. In silica brick, the true density of tridymite crystal is smallest, the linear expansion rate is small, the thermal stability is better than quartz, thermal conductivity is good, refractoriness under load is high, slag corrosion resistance is strong, is the most stable volume form in quartz. In good firing silica brick, the content of tridymite is the highest, accounted for 50% ~ 80%. Cristobalite takes second place, only accounted for 10% ~ 10%. The content fluctuation of quartz and glass phase is in 5% ~ 5%.

When working temperature is below 600 ~ 700 ℃, silica brick volume change is bigger, the resistance to thermal shock performance is poor, thermal stability is not good. If the long-term work under the temperature of coke oven, masonry is easily broken.

The key to determine whether thermal stability of silica brick is true density, the size of true density is to determine one of the important marks of the quartz.

Silica brick is the ideal refractory products of coke oven, the important parts of the modern large and medium-sized coke oven (such as the combustion chamber, ramps and regenerator) all use silica brick to build.

The Molding and Methods of Refractory Brick

Refractory brick’s molding in the manufacturing process, refers to the refractory raw materials recuring to outside force and the model, making the blank will be processed into specified dimension and shape. However, the flow castable’s construction of the latest development does not need basically external forces.

The molding of refractory brick, firstly is to satisfy the using demand of the products, when refractory brick masonry, the requirement of products must have a certain shape, precise size, and enough strength. Secondly, molding is also the efficient way to improve the physical and chemical properties of products, by shape can improve the organizational structure of products. Refractory brick has a lot of molding methods, the traditional processing methods according to how much moisture content can be divided into:

Semi-dry method: its blank moisture is around 5%, suitable for blank of different clinker content(50% 100%).

Plastic method: its blank moisture is around 15%, suitable for manufacturing large or complicated shape of the products.

Grouting method: its blank moisture is around 40%, is suitable for all kinds of hollow thin-walled refractory materials in production.

The modeling methods of refractory brick have a lot, the common used molding ways contain organic pressure molding, vibration molding, extrusion molding, ramming forming, isostatic pressure molding, casting molding, grouting, etc.

Choose what kind of molding method, mainly according to the nature of the plaster, body shape, size and other technical requirements. In addition to most of the refractory brick is made of machine pressure forming, vibratory molding is used for special-shaped body, the extrusion molding is generally used in tubular blank, slip casting molding is used for thin wall body shape.

The Characteristics and Application of Lightweight Refractory Materials

Lightweight refractory material is also known as heat insulation refractories and insulation refractories, refer to the high porosity, small volume density, low thermal conductivity, has the thermal insulation performance of refractory materials. It includes insulating refractory products, refractory fiber and refractory fiber products.

As a kind of refractory material, lightweight refractory has a certain high temperature mechanical properties and good volume stability, is all sorts of high-temperature thermal equipment necessary. Compared with dense refractory material, the lightweight refractory filled with gas shows high apparent porosity, small volume density, good insulation performance, has the screened effect on heat. Therefore, the main characteristics of lightweight refractory material are:

High apparent porosity

A main performance index to measure lightweight refractory material quality is the porosity. Pore is made of the pore in the refractory raw materials and intergranular porosity after forming.

Small volume density

The volume density of lightweight refractory is small, no more than 1.3g/cm³. At present, volume density of common lightweight refractory industry is 0.5~1.0g/cm³ in industry.

Low thermal conductivity

Under unit the temperature gradient, within the unit time through unit vertical heat. It is the important performance index of lightweight refractory material quality, is also the important index of the design of thermal performance design. It indirectly reflects apparent porosity and bulk density of the products.

Low compression strength

Lightweight refractory material, due to large apparent porosity, low bulk density, not form a compact connection between crystals. So relative to the dense refractory material, its pressure strength is low, wear-resisting performance is poor.

Application

Lightweight refractory material is important component part of kiln, boiler, the thermal container and other equipment, is widely used in industry. Because of the lightweight refractory material’s high apparent porosity, occupies the irreplaceable position in the high efficiency and energy saving

Several Steps of Fire Clay Brick Production

Our company mainly produces fire clay brick, has advanced technology, strong technical force, complete detection equipment. Fire clay brick production has several steps:

Borrow earth. The soil bake brick uses taking from two feet deep of the ancient soil under the earth’s surface. The layer of soil color is slightly deeper than the overburden，it formed in eighty thousand to about eighty thousand years ago. At that time, the earth’s climate is warm and moist, rich biological role makes this period of the formative soil soft and sticky, is good material of fire brick.

Dig out of clay, in the process of passing about half a year of open air accumulation, let sunshine illuminate, snow and rain frozen erosion, make its internal decompose and loose, then by manual crushing, sieving, leaving only fine pure soil.

Add water into pour soil, make it moist, and then repeatedly refine, or use the cow power trample, make it become thick mud, human through mud and refine need five to six times, the process plays a crucial role in the quality of the brick.

Fill soil into wooden blocking mode, after compaction, use iron wire to scrape off the excess sludge and become blank shape. Before blocking, need to sprinkle a layer of fine sand under wooden underground, in case of mud and ground adhesion.

After stripping the brick, need to place sun back to dry in the shade, to prevent exposure to make brick bad and appear crack and deformation.

After waiting for adobe completely dry (about one to two months), then into the kiln, the process is one of the most important link in the whole process of brick, common brick uses coal as fuel, while compactness higher feed slurry brick uses wheatgrass, pine slowly burn, etc.

How to Solve the Excessive Shrinkage Cavity Problem of Fused Cast AZS

For the excessive shrinkage cavity problem of fused cast AZS, can carry on the improvement in the mold design, the control of sodium oxide content, the casting operation.

The design method of improvement

The residual shrinkage cavity of no shrinkage cavity fused cast AZS is closely related to the mold design, excessively increase the size of the AZS brick, cut off more shrinkage cavity, but the AZS brick has high incidence of crack, rising costs. Therefore, by a large number of tests, grasp different shapes and the use of the best parts of the product design, reached a reasonable balance in all respects.

Control of sodium oxide

The content of sodium oxide has close relationship with the short of bulk and excessive shrinkage cavity of fused cast AZS, through the theoretical analysis and experiment validation, ultimately determine the appropriate add amount.

The improvement of the casting operation

For a large no shrinkage cavity fused cast AZS, sometimes first time casting is not able to complete, need secondary casting.

The physical properties of the Refractory Materials

Structural properties

Macroscopic organization structure of refractory material is heterogeneous body composed of solid material and gas hole. Porosity is the important factors influencing the products under normal temperature and high temperature performance, especially under the condition of high temperature, is products to the outside world of erosion resistance ability is greatly reduced. Reason of gas hole formation: when products molding, the air in the material is completely ruled out. After material moisture ruled out, leaving space. Raw material calcined is inadequate, some should decomposition of salt is the complete decomposition, should be burning ingredients to burn completely. The material composition is uneven, when high temperature firing, contraction is uneven, etc.

porosity

The porosity of refractory can be divided into: closed porosity, closed in the products is not connected with the outside world. Open pores, closed at one end and the other end connected with the outside world, for fluid filling. Cut-through pore, The two sides of the cut-through products, get through for the fluid.

Bibulous rate

Bibulous rate is absorbed by all the open pores in the products of water quality and the quality of the dry sample ratio. Because the bibulous rate of determination method is simple, in actual production often used for identifying the quality of raw material calcined. The raw material calcined is the better, the bibulous rate value is the lower.

Bulk density

The definition of bulk density is the ratio of dry weight and total volume of products, also known as a volumetric weight. Volume density intuitively reflects the degree of the density of the products, it is an important measure indicator of dense refractory products quality. But in the production of lightweight insulation products, in order to reduce the heat capacity and thermal conductivity, people use various means to reduce the products volume density.

True proportion

The quality of dry material and its true volume (not including pore volume) ratio. The true proportion of refractory material, can reflect the material composition of purity or the degree of crystal structure transition, proportion, etc.

The thermal properties

Thermal expansion

Thermal conductivity