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Refractory material production process introduced

According to the degree of compactness and shape of the product, there are sintering method, casting method and melt injection method. Sintering method is the raw materials of raw materials pre-baked clinker, broken and sieved, and then by a certain ratio and raw materials mixed, through the molding, drying and firing.

Casting method is the raw materials through the ingredients mixing and fine grinding process, in the high temperature melting, direct casting, cooling crystallization, annealing products. Their body is dense, high mechanical strength, high temperature structural strength, good slag resistance, the use of the range continue to expand.

The melt blown method is a method in which a batch is melted and then blown into a fiber or a hollow sphere by blowing it with high pressure air or superheated steam. Products are mainly used for light refractory, heat insulation materials, but also made of powder or granular amorphous refractory, temporary use of tar, asphalt, cement, phosphate, sulfate or chloride and other bonding agent cement, without Forming and sintering directly.


Characteristics of Global Refractory Industry Development

At present, the global production of refractory materials is about 45 million tons, China's refractory production accounts for about 65% of the world's total refractories, other production is mainly concentrated in the EU, CIS, the United States, Japan and South Korea and other countries and regions.

Global refractory industry development has the following characteristics:

1.Through the mergers and acquisitions, reorganization and elimination of backward to improve the concentration of refractory industrial production

Developed countries since the nineties of last century, mergers and acquisitions, restructuring and operation in the market economy in the natural phase out, so that the rapid increase in production concentration, such as Japan in the 1950s, more than 100 refractory production enterprises, for decades, through mergers and acquisitions , Reorganization and collapse in the market economy tide, trademark cancellation and other forms, so far, only more than 60 refractory enterprises. Another example is the 1970 US 7 independent refractory production enterprises, through several mergers and acquisitions, merged into a company in 2001, that is, "RHI refractories."

2.The total amount of refractory material gradually weakened, the product added value steadily improved
In the premise of the relatively stable demand for refractory materials, due to the continuous adjustment of refractory variety structure, product quality continues to improve, will reduce the demand for refractory materials, but the value-added products is still steadily improving.

Developed countries such as the United States, Japan and Europe have shown a positive growth trend in the growth rate of sales of refractories and higher than the growth rate of refractory production. In particular, some countries refractory production declined year by year, while sales revenue grew year by year.

3.Refractory industry to the formation of large enterprise groups direction

At present, through hundreds of mergers and acquisitions and corporate self-development, refractory industry formed a number of large enterprise groups. Large-scale enterprise groups to make the degree of intensive production, industrial chain gradually extended, and use its strong economic and technological strength and brand advantage, in order to seek greater profit margins.


Present Situation and Technical Progress of Refractory Materials in China

Reform and opening up more than 30 years, China's refractory industry has made great progress. China's refractory production ranks first in the world, refractory quality and variety has also been greatly improved and developed, refractory technology is also rapidly close to the international advanced level. However, China's refractory industry, there are still many problems, such as: high consumption of refractories; refractory production plants, low concentration; refractory product quality and poor stability; innovation is not enough; research and development work mainly concentrated in the material formula - composition - structure and performance, while the production process control and the use of refractory material is not enough attention.

At present, China's economic development has entered a transition period. Refractory users a large number of excess capacity, economic benefits, environmental requirements are increasingly stringent. These have caused great difficulties for refractory enterprises. The reasons for these problems are multifaceted, and the transformation of China's national economic development model, but also with the refractory industry itself is closely related to the problem. For example, the existence of a large number of small and medium enterprises that technological advantages and large-scale production advantages and did not give full play to the low level of small and medium enterprises to survive opportunities. The production of these problems and production management, scientific and technological progress and refractory workers thinking and other factors, can not be quickly resolved.

In the field of materials, refractories are a small, traditional branch, and it does not get enough attention. It is indispensable basic material of the national economy, but also the most complex microstructure of the material. It has the characteristics of multi-component, multi-particle and heterogeneous composite structure, and it is much more difficult to study the structure than other materials. Therefore, both from the number and depth of research than other materials behind, the development of science and technology is relatively slow. Looking back over the past half century, there are only two important technologies that affect the development of refractory materials.


Brief Analysis on the Characteristics and Classification of Refractory Materials

Refractory material is refractory not less than 1580 ℃, have good resistance to thermal shock and chemical erosion, low thermal conductivity and low expansion coefficient of non-metallic materials. Refractory degree refers to the refractory cone specimen in the absence of load conditions, resistance to high temperature effect without softening the melting of the Celsius temperature.

(1580 ~ 1770 ℃), high-grade refractory materials (1770 ~ 2000 ℃) and special refractory materials (above 2000 ℃); according to the chemical characteristics of acid refractory materials, according to the chemical characteristics of refractory materials, Neutral refractory materials and alkaline refractories. In addition, there are refractory materials for special occasions.

Acid refractory material to silicon oxide as the main component, commonly used silica brick and clay brick. Silica brick is silicon oxide containing more than 94% of the silicon products, the use of raw materials are silica, waste silicon brick, and its anti-acid slag erosion ability, load softening temperature is high, repeated calcination volume does not shrink, or even slightly inflated; But it is susceptible to alkaline slag erosion, poor thermal shock resistance. Silicone brick is mainly used for coke oven, glass melting furnace, acid-making steel furnace and other thermal equipment. Clay brick with refractory clay as the main raw material, containing 30% to 46% of alumina, is a weak acid refractory, heat shock resistance, acid slag corrosion resistance, widely used.

Neutral refractories with alumina, chromium oxide or carbon as the main component. Alumina containing 95% or more corundum products is a wider use of high quality refractories. Chromium brick as the main component of the steel brick on the corrosion resistance of steel slag, but the thermal shock resistance is poor, high temperature load deformation temperature is low. Carbon refractories are carbon brick, graphite products and silicon carbide products, the thermal expansion coefficient is very low, high thermal conductivity, good thermal shock resistance, high temperature strength, acid and salt erosion, especially weak acid Better resistance, from metal and slag wetting, light weight. Widely used as high temperature lining materials, but also for oil, chemical kettle lining.

Alkaline refractory materials to magnesium oxide, calcium oxide as the main component, commonly used is magnesium brick. Magnesium oxide containing 80% to 85% magnesium oxide is very resistant to alkaline slag and iron slag, and the refractoriness is higher than that of clay brick and silica brick. Mainly used for flat furnace, oxygen converter, electric furnace, non-ferrous metal smelting equipment and some high-temperature equipment.

Refractories for special applications include high temperature oxide materials such as alumina, lanthanum oxide, beryllium oxide, calcium oxide, zirconia and the like, refractory compound materials such as carbides, nitrides, borides, silicides and sulfides Etc .; high temperature composite materials, mainly metal ceramics, high temperature inorganic coating and fiber reinforced ceramics.

Common refractories:

Frequently used refractory materials are AZS brick, corundum brick, direct combination of magnesia-chrome brick, silicon carbide brick, silicon nitride combined with silicon carbide brick, nitride, silicide, sulfide, boride, carbide and other non-oxide refractories ; Calcium oxide, chromium oxide, alumina, magnesium oxide, beryllium oxide and other refractories.

Frequently used insulation refractories are diatomaceous earth products, asbestos products, thermal panels and so on.

The refractory refractory material is made of refractory refractory, refractory castable, refractory castable, refractory castable, refractory castable,


Environmental significance of composite refractory materials

The composite refractory material has been developed rapidly in recent years because of its high strength and low density, which is a kind of popular material instead of steel production. In particular, the technology of glass fiber reinforced composite refractory has been mature and In the automotive industry has been a lot of applications. However, the glass fiber is harmful to the human body and is easy to be bonded after melting, resulting in difficulty in recycling.

The natural fiber is recyclable, biodegradable, available, renewable, incineration when no toxic emissions, landfill biodegradable, and can be recycled; natural fiber can be used one-step molding, bonding with other materials Easy, the production process generally do not use adhesive. So natural fiber is environmentally friendly materials. Natural fiber in the energy advantage is also very obvious, such as Ma fiber growth period is short, the growth environment is not high, the growth process without pesticides and fertilizers. Natural fiber in the growth, harvest and processing of energy consumption less, the production process without "three wastes" pollution, the use of the process without harmful free chemical precipitation.

In addition, natural fiber composite refractories generally use polyester or polypropylene as the base resin, the use of wood fiber, hemp fiber and other natural fibers (straw, bamboo, sugar cane, coconut shell, etc.) as a reinforcing material. Substrate resin is cheap, fiber raw materials from a wide range of prices are also very low, so the natural fiber composite refractory materials have other composite materials can not match the price advantage. Moreover, the strength of natural fiber composite refractories is also higher than the glass fiber composite refractory, the use of natural fiber composite refractory instead of glass fiber composite refractory manufacturing auto parts can achieve 5% to 15% of the lightweight.

Now, the production of natural fiber composite refractory materials and products have been developed, because the use of direct extrusion injection molding process, so the composite material only experienced a heating process, which can reduce the natural fiber such heat sensitive materials heat degradation. Production of automotive exterior trims (including hoods, spoilers and fenders, etc.) is produced by on-line production using extrusion molding or extrusion molding.

In short, the natural fiber reinforced composite refractory material is a very promising environmentally friendly materials. According to expert evaluation, 5 years after its application will exceed the glass fiber.


China Glass Refractory Materials development analysis on the overall situation

Over the past decade, China's glass industry with refractory materials have made great progress, integrated in the large-scale float glass kiln kiln, from 3 to 4 years to 5 to 8 years, and all the materials to achieve the localization, greatly Narrowing the gap with the advanced level of foreign countries, for the glass industry with the future development of refractories, laid a solid foundation. But with the further development of the glass industry needs and foreign advanced level, there are still many problems to be solved.

China's accession to the WTO, foreign high-quality low-cost products can drive straight into the same time, China's quality products into the international market has become more convenient. Seize the opportunity to seriously analyze China's glass industry refractory problems and the gap with the world's advanced level, to take the right countermeasures, as soon as possible to narrow the gap with the developed countries, catch up with the world's advanced level, which will be our response to WTO challenges Best response. The following will be based on the current main problems, combined with the future development of thinking, put forward some suggestions.

First, bigger and stronger with strong technical innovation strength and international competitiveness of the Ministry of Industry and Trade integration of large supporting refractory leading enterprises, so as to enhance the overall level of the industry, driving the development of the industry as the dominant force.
At present, the glass industry refractory industry there are many enterprises, small scale, decentralized, low-level redundant construction, their own war, the market disorderly competition and so on, resulting in the overall level of the industry to improve slowly. In recent years, China has built more than 30 refractory refractory enterprises, these enterprises in recent years despite the majority of different degrees of progress, but most of the smaller production scale, weak technical force, backward technology and equipment , Product quality is difficult to guarantee. Sintered refractories have a similar situation. Thus forming a common product over the one hand, on the other hand high-end products still need to import the situation, and because of these enterprises cheap dumping, resulting in market chaos, a backbone enterprises to improve product quality barriers. Therefore, there is an urgent need for strength of the industry and trade integration of refractory companies,just like Zhengzhou Shixing Special Refractory Co., Ltd.It is guaranteed to provide reliable quality refractory refractory materials. This kind of company can use its own strong strength to integrate resources, bigger and stronger, and guide the industry to continuously improve the overall level, climb the new peak. The so-called bigger is the company to have their own control of a certain size of cast refractories, alkaline refractories, silica brick, zirconium, zirconia corundum, sillimanite, mullite refractories and new unshaped refractory production base And supporting system, can provide the whole kiln quality supporting refractory materials to meet the entire glass industry, including the glass fiber industry, the demand for refractories. The so-called strong, is to rely on the new strong, make full use of strong technical advantages, continuous technological innovation, enhance the overall level of the industry, making it an international competitiveness of large refractory supporting companies.

Second, the design of glass melting furnace, the production of refractory materials, the operation of the furnace, maintenance, use and refractory production and use of scientific research between the four closely, is to extend the kiln kiln, as soon as possible to reach the international advanced level One of the important conditions.
To extend the kiln kiln must have two conditions: First, the integration of industry and trade supporting the refractory company, to provide all kinds of high-quality refractory refractory materials; the second is to design, production, use and research Close combination, to play their respective advantages, so that the whole kiln refractory configuration more reasonable, especially the kiln more than 8 years old kiln, has not entirely rely on to improve the quality of refractories can be achieved. Superb design, careful operation, maintenance and management of quality and supporting the supply of refractory materials must be closely integrated in the past, the kind of each tube for a period of non-communication, disconnected from each other, the lack of the overall concept of the situation is the long melting of the kiln kiln One of the important reasons.


Selection and Masonry for Glass Furnace Refractory

1. dense chrome brick

It has the best anti-high temperature E glass erosion performance, the erosion of the glass is basically no pollution, it has become E glass unit kiln preferred high-quality refractory brick.

The main technical indexes are Cr2O3 content> 94%, porosity <15 bulk="" density=""> 4.24g / cm3, and the erosion loss is only 1/10 of that of dense zirconium brick. The In the E glass kiln kiln unit kiln directly contact the high temperature glass liquid melting part of the wall, the melting part of the high temperature parts of the bottom, the main channel wall and the bottom of the pool, the transition channel wall.

2. dense zirconia brick

The corrosion resistance of the brick is slightly lower than that of the dense chrome oxide brick, and the isostatic pressing method is used. The technical index is ZrO2> 65%, the apparent porosity is less than 2.0%, the bulk density is about 4.25g / cm3, E glass in the temperature of more than 1370 ℃ there is erosion. The bottom of the melting part, the transition path, the bottom of the forming channel, and the flow path and the trough and the trough of the molding glass are used in the E glass kiln. In addition, dense zircon bricks are also used as a backing brick for dense chrome bricks.

In recent years, many refractory enterprises in China have also introduced foreign technology and equipment, but also produced the use of isostatic pressing molding sintered dense zirconium brick, has been the domestic glass, glass furnace furnace part of the application.

3. Standard zircon brick

The brick ZrO2 content of about 66%, bulk density of 3.7g / cm3, with good thermal stability and anti-peeling. The use of the powder in the erosion of the more serious mouth of the mouth of the mouth and the back wall, melting furnace observation hole brick and access to the flame of the chest wall and roof brick, burner brick. But there are also the use of AZS burner brick and the use of mullite brick for the transition brick and kiln side of the gap brick.

4. sintered mullite tiles

The chemical composition of the brick is Al2O3> 74%, SiO22.2%. Bulk density of 2.5g / cm3, the main purpose is the standard chrome lining brick, melting the chest wall and the front wall, access flue lining brick, large arch and foot outlet mouth outside the brick, heat exchanger entrance flue outside the wall Wait. There is also a mullite brick which is melted by mullite crystal and has better anti-high temperature creep and heat shock resistance. It can be used as kiln large and flame space chest wall. The effect is very good, the current localization has also been successful.

5. Fused zirconia corundum brick (AZS brick)

The chemical composition of the brick is ZrO234%, Al2O349.2%, SiO2 15.9%. Bulk density of 3.85g / cm3, the main purpose is to melt the mouth of the mouth of brick and brick mouth.

6. Fused chrome corundum brick

The chemical composition of the brick is Cr2O328.3%, Al2O358.3%, MgO, Fe2O35.2%. Bulk capacity of about 3.4g / cm3. Mainly used in the heat exchanger at the entrance of the flue interface brick.