Therefore, in the process of understanding and researching industrial kiln building materials, it is necessary to describe and introduce the types of refractory bricks. First, we will introduce the silicon-aluminum refractory brick. It is reported that it is based on the AL2O3-Si

Refractory bricks are basic materials serving high temperature technology and have a very close relationship with various industrial kilns . Various industrial kilns such as glass kilns have different requirements for refractory bricks, the basic material that constitutes their main body, due to their different uses and conditions of use. Different types of refractory bricks also show different basic characteristics due to differences in chemical mineral composition, microstructure and production processes. Therefore, in the process of understanding and researching industrial kiln building materials, it is necessary to describe and introduce the types of refractory bricks.

first introduces the silicon-aluminum refractory brick. It is reported that it is based on the AL2O3-SiO2 binary system phase diagram as the basic theory, and mainly includes the following types.

(1) Silica brick refers to refractory bricks containing more than 93% SiO2 and is the main variety of acid refractory bricks. It is mainly used for building coke ovens, and is also used in the vaults and other load-bearing parts of thermal kilns for various glass, ceramics, carbon calciners, and refractory bricks. It is also used in the high-temperature load-bearing parts of hot blast furnaces. It is also used, but it should not be used in thermal equipment with temperatures below 600°C and large temperature fluctuations.

(2) Clay bricks Clay bricks are mainly composed of mullite (25% ~ 50%), glass phase (25% ~ 60%) and cubic quartz and quartz (up to 30%) composition. Usually hard clay is used as the raw material, and the clinker is pre-calcinated, and then mixed with soft clay, formed by a semi-dry method or a plastic method, and fired at a temperature of 1300 to 1400 C to produce clay brick products. You can also add a small amount of water glass, cement and other binding agents to make unfired products and amorphous materials. It is a commonly used refractory brick in blast furnaces, hot blast furnaces, heating furnaces, power boilers, lime kilns, rotary kilns, glass kilns, ceramics and refractory brick firing kilns.

(3) high alumina brick . The mineral composition of high alumina brick is corundum , mullite and glass phase. Its content depends on the AL2O3/SiO2 ratio and the type and quantity of impurities. The refractory bricks can be classified according to the AL2O3 content. classification. The raw materials are high-alumina bauxite and sillimanite natural ores. There are also those mixed with fused corundum, sintered alumina, synthetic mullite, and clinker calcined with alumina and clay in different proportions. It is mostly produced by sintering method. But the products also include fused cast bricks, fused granular bricks, unfired bricks and unshaped refractory bricks. High alumina bricks are widely used in the steel industry, non-ferrous metal industry and other industries.

(4) corundum brick , corundum brick refers to a refractory brick with an AL2O3 content of not less than 90% and corundum as the main phase. It can be divided into sintered corundum bricks and fused corundum bricks.

Refractory brick numbering rules:

General The brick number of refractory brick starts with the word "T", which is the second letter of the Chinese pinyin of "Tong", the brick numbers of general bricks are: T-1, T-2, T-3……..T-105.The Z, C, S, K and J after the T are respectively "straight", "side", "vertical", "wide" and "foot" for straight bricks, side wedge-shaped bricks, wide wedge-shaped bricks and arch foot bricks. The first lowercase letter of the Chinese pinyin . The dash is followed by the sequence number. In the

code, Z, C, S, K and J are respectively the first Chinese pinyin of "straight", "vertical", "wide" and "foot" for straight bricks, side wedge bricks and arched foot bricks. uppercase letter.

The straight brick letters are followed by the hundreds and tens digits of the brick length a, followed by the tens digits of the brick thickness C. After the wedge-shaped brick letters are the hundreds and tens digits of the distance b between the big and small heads. Next is the ten-digit number of brick thickness C.

wedge-shaped brick letters are followed by the hundreds and tens digits of the distance b between the big and small heads, followed by the tens and above numbers of the large head size a and the small head size a1. The K at the end of the number is the first lowercase letter of the Chinese pinyin for the word "Kuan" in the staggered wide bricks.

After the letters of the arched bricks are the hundreds and tens digits of the length L of the slope. Next is the ten-digit number of the tilt angle a. The

universal brick covers a wide range of content due to its versatility, roughly including the following two aspects.

1, including standard bricks and common products

T-3, T-6, T-19, T-22, T-38, T-41 are standard bricks. Brick numbers other than standard are classified into general products, special-shaped products, and special-shaped products.

2, including products of different materials

The same brick number includes clay bricks, semi-silica bricks, silica bricks, lightweight clay bricks (LZ)-65, (LZ)-55, (LZ)-48 and other different materials . It should be noted that not all bricks have these materials, and some bricks do not have lightweight clay bricks.

In addition, there are some other regulations for general bricks: the shape and size of furnace door arch refractory products, brick number E-1-E-11; blast furnace clay and high alumina refractory products, brick number G-1-G- 6 and so on, these are also part of the refractory bricks standard. The refractory degree of

refractory bricks is different from the melting point. The melting point is the temperature at which the liquid phase and solid phase of the crystal are in equilibrium. The composition of most refractory bricks is multi-phase heterogeneous materials. It does not have a certain melting point. It is a gradual process from the beginning of liquid phase to complete melting. In a wide range of high temperatures, solid and liquid phases coexist. Therefore, if you want to characterize the softening and melting characteristics of refractory bricks at high temperatures, you can only use Measured by refractory resistance. Therefore, refractoriness is the temperature at which a multiphase body reaches a certain degree of softening.

The refractory degrees of some commonly used refractory bricks are as follows:

1, clay bricks 1610~1750℃

2, silica bricks 1690~1730℃

3, crystalline silica 1730~1770℃

4, hard clay 1750~1770℃

5, high aluminum Brick＞1770 ~2000℃

6, magnesia refractory bricks >2000℃

7, dolomite refractory bricks >2000℃

Although refractory degree is an important technical indicator for evaluating refractory bricks, it cannot be used as the upper limit of the use temperature of refractory bricks. The test standard for the refractoriness of high alumina bricks is GB/T 7322 "Test Method for Refractory Resistance of High Alumina Bricks".