What Is Refractory Brick?

Refractories are generally divided into two types, namely unshaped refractories and shaped refractories. Unshaped refractories, also called castables, are mixed powdery granules composed of multiple aggregates or aggregates and one or more binders. When used, they must be mixed with one or more liquids and stirred uniformly. Strong liquidity. Shaped refractory materials generally refer to refractory bricks, and there are standard rules for their shapes, and they can also be temporarily processed when needed.

Refractory brick

Self property

1. Chemical composition: The main ingredients determine the quality and characteristics of the refractory

2. Bulk density: weight per unit volume, high density, indicating good density and high strength, but

According to the composition of refractory bricks, it can be divided into five categories, namely: silicon-aluminum-based refractory bricks, alkaline series refractory bricks, carbon-containing refractory bricks, zirconium-containing refractory bricks, and heat-resistant refractory bricks. Any stove is not built with only one type of refractory bricks. It requires the use of different refractory bricks. The components of these five major types of refractory bricks are described in detail below.

1. Silica-alumina refractory bricks. It is reported that the basic theory is based on the phase diagram of the binary system AL2O3-SiO2, which mainly includes the following.

(1) Silicon bricks refer to refractory bricks containing more than 293% SiO, and are the main varieties of acid refractory bricks. It is mainly used for masonry coke ovens, but also for the vaults and other load-bearing parts of various glass, ceramics, carbon calcining furnaces, refractory bricks. It is also used in high-temperature load-bearing parts of hot blast stoves, but it should not be used in Used in thermal equipment below 600 ° C and with large temperature fluctuations.

(2) Clay bricks. Clay bricks are mainly composed of mullite (25% to 50%), glass phase (25% to 60%), cristobalite and quartz (up to 30%). Generally, hard clay is used as the raw material, the mature material is calcined in advance, and then the soft clay is mixed, and the semi-dry method or the plastic method is used to mold the clay brick products at a temperature of 1300-1400 C. You can also add a small amount of water glass, cement and other binders to make unfired products and amorphous materials. It is a commonly used refractory brick in blast furnace, hot blast stove, heating furnace, power boiler, lime kiln, rotary kiln, ceramic and refractory brick firing kiln.

(three)

Refractory

1. High alumina brick: Al2O3 content is more than 75, and the fire resistance is higher than

The public welfare nature of refractory raw materials mainly depends on the mineral composition and particle composition of the raw materials, and

With the continuous development of China's cement industry, higher requirements have also been placed on refractories. The refractory industry, which has long relied on extensive economic growth, should increase its adjustment efforts to meet the needs of the new situation.

China's cement industry refractory industry has problems such as low industry concentration, vicious competition, and shortage of raw material resources. Only by accelerating the restructuring and integration of cement kiln refractories production enterprises can we adapt to the rapid development of the cement industry. At the same time, enterprises should also strengthen cooperation with scientific research institutes and user units, increase cooperation between industry, university and research, achieve new breakthroughs in green refractory technology, and strive to short-term, in some key green refractory technology and Substantial breakthroughs were made in the promotion and application.

The strategy of developing green refractories is an important development strategy related to the sustainable development of China's current and future refractories industry.

And the forthcoming "Refractory Raw Material Industry Access Standards" will definitely promote the elimination of backward production processes and equipment in the next few years, foster leading enterprises, and promote the industry's development towards large-scale and intensive development.

Of course, while developing green refractory materials, product quality must also be guaranteed. The main reasons for the low life of refractory materials are the backward production equipment of the manufacturers, and the use of friction brick presses for molding. The batching, forming, firing, and inspection processes have low levels of automation, large product quality fluctuations, and large dimensional deviations; improper masonry methods . In use, in order to prevent the refractory material from falling bricks, excessive use of steel plate locks, resulting in a large expansion of the refractory material during heating, excessive pressure to damage the refractory brick; low degree of fine management and so on.

In order to solve the problem of short service life of refractory materials, some enterprises have started to develop energy-saving products, such as replacing silicon oxide bricks with higher thermal conductivity with silicon thermal bricks (high aluminum silicon carbide materials) to reduce heat loss and reduce tons of cooked steel. Material heat consumption, saving energy. And use magnesium iron spinel bricks instead of direct magnesium chromium bricks, instead of the use of magnesium chromium bricks in rotary kiln, effectively avoid chromium pollution.

In fact, cement enterprises should rationally choose refractory materials according to the cement kiln process conditions and the requirements of raw clinker and fuel. For example, high-aluminum bricks with high strength, low thermal expansion rate, and good thermal shock resistance should be used to reduce refractory materials during heating. Damage. At the same time, it is necessary to optimize the design scheme according to the actual use situation, improve the level of fine management, increase the operation rate of the cement kiln, and reduce the consumption of refractory materials per ton of clinker.

At the review meeting of the "Rules for the Use of Refractory Materials in Cement Rotary Kilns" organized by the China Building Materials Federation, the participating experts reviewed and approved the standard submission draft for review. It marks the successful completion of the first technical regulations for the use of refractory materials in domestic and foreign cement kilns, which will be of great significance for promoting the standardization of refractories for cement kilns, promoting the development of the industry, and transforming and upgrading. ^[3]