Usually refers to refractory materials with high content of acidic oxides such as SiO2. Such as siliceous, semi-siliceous, fused silica, and recombined fused silica refractories. The content of silica stipulated in different countries is different. The lower limit is usually between 65% and 80%. It is mainly composed of silicic acid or aluminum silicate and is a refractory material that easily generates salt under the action of high temperature and alkali.

Usually refers to a refractory material containing a considerable amount of silica.

Acid refractory mainly includes

(1) Medium acid semi-siliceous refractories and pyrophyllite refractories; (2)Weak acid clay refractories. The main feature of acidic refractory is that it can resist the erosion of acidic substances (acidic slag) at high temperatures, but it is easy to react with alkaline substances (alkaline slag). Refractory materials also fall into this category.

Related information

There are many kinds of refractory materials, which are usually divided into ordinary refractories (1580-1770℃), advanced refractories (1770-2000℃), and super-grade refractories (above 2000℃) according to their refractoriness; Neutral refractories and alkaline refractories. In addition, there are refractory materials for special occasions.

Carbon refractory materials include carbon bricks, graphite products, and silicon carbide products, which have low thermal expansion coefficient, high thermal conductivity, good thermal shock resistance, high-temperature strength, corrosion resistance of acid, alkali, and salt, and are not affected by metal and slag. moisturizing and lightweight. Widely used as high-temperature furnace lining material, also used as autoclave lining in petroleum and chemical industry.

Alkaline refractories are mainly composed of magnesia and calcium oxide, and magnesia bricks are commonly used. Magnesia bricks containing more than 80% to 85% of magnesia have good resistance to alkaline slag and iron slag, and their refractoriness is higher than that of clay bricks and silica bricks. Mainly used in the open hearth, oxygen blowing converter, electric furnace, non-ferrous metal smelting equipment, and some high-temperature equipment.