A brief introduction to high alumina bricks

Release Time:

2022-08-22

1. Introduction

Aluminum silicate refractory products with aluminum oxide (Al2O3) content higher than 48%. A neutral refractory with an alumina content of more than 48%. It is formed and calcined from bauxite or other raw materials with high alumina content. High thermal stability, refractoriness above 1770℃. It has good slag resistance and is used for the lining of steelmaking electric furnaces, glass melting furnaces, cement rotary furnaces, etc. High-load soft, low-creep high-alumina bricks are made of super-grade bauxite, fused corundum, and fused mullite as the main raw materials. Refractory materials. This product has the advantages of small high-temperature creep, strong corrosion resistance, good thermal shock stability, etc. It is suitable for large and medium-sized hot blast stoves. It is the need for high-quality, imported refractory materials for my country's new hot blast stoves. A road to success that has been included in the project "Project Spark".

Second, the production process

The production process of high-alumina bricks and multi-clinker clay bricks is similar, the difference is that the proportion of clinker in the ingredients is higher, which can be as high as 90-95%. Higher, such as I, II and other high-alumina bricks are generally 1500 ~ 1600 ℃ when fired in a tunnel kiln. China's production practice has proved that high alumina clinker is strictly selected and graded before crushing, and stored in a graded manner, and the co-fine grinding method of bauxite clinker and combined clay can improve product quality.

3. Raw materials

According to different resource conditions and product requirements, the following types of raw materials can be used: high alumina bauxite mainly composed of hydrous alumina minerals (monohydrate, gibbsite, etc.); sillimanite group minerals (including blue crystals) Stone, andalusite, sillimanite, etc.); synthetic raw materials, such as industrial alumina, synthetic mullite, fused corundum, etc. China's high-alumina vanadium soil is rich in resources and has excellent texture, and its production areas are mainly distributed in Shanxi, Henan, Hebei, Guizhou, Shandong and other places. The high alumina vanadium produced is mainly a mixture of two minerals, gibbsite (α-Al2O3·H2O) and kaolinite.

4. Features

a. Refractoriness

The refractoriness of high-alumina bricks is higher than that of clay bricks and semi-silica bricks, reaching 1750~1790℃, which belongs to refractory materials.

b. Softening temperature under load

Because of the high Al2O3 in high alumina products, less impurities and less fusible glass body, the softening temperature under load is higher than that of clay bricks, but because mullite crystals do not form a network structure, the softening temperature under load is still lower than that of silica bricks.

c. Slag resistance

There are more Al2O3 in high alumina bricks, which are close to neutral refractory materials, and can resist the erosion of acid slag and alkaline slag. Because it contains SiO2, the ability to resist alkaline slag is weaker than that of acid slag.

5. Purpose

Mainly used for masonry blast furnace, hot blast stove, electric furnace roof, blast furnace, reverberatory furnace, rotary kiln lining. In addition, high alumina bricks are also widely used as open hearth regenerative checker bricks, plugs for pouring systems, nozzle bricks, etc. However, the price of high-alumina bricks is higher than that of clay bricks, so it is not necessary to use high-alumina bricks where clay bricks can meet the requirements.

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A brief introduction to high alumina bricks