What are the Refractory Materials That Belong to Refractory Materials?

With mullite, corundum or carbon (Al2O3, ZrO2, CrO3, SiC) as the main crystalline phase, it can resist the chemical corrosion of acid slag, alkaline slag, flux and other refractory materials at high temperature.

Strictly speaking, neutral refractories refer only to carbon refractories, including carbon bricks, graphite silicon carbide products, and the like. There are also high-aluminum refractories with high Al2O3 content, such as sillimanite bricks, mullite bricks, corundum bricks, etc., which are acidic and tend to be neutral. The silicon carbide grades such as aluminum carbon bricks, zirconium carbon bricks, alumina-silicon carbide-carbon bricks, silicon nitride-bonded silicon carbide bricks, etc., which have been developed in recent years, are also neutral refractories. The neutral refractory product can be used as a lining for the bottom of the blast furnace, a lining of the hearth and the belly of the furnace, an aluminum electrolytic cell, a calcium carbide furnace and a ferroalloy furnace, a steel drum, a plating tank, a reaction tank, an autoclave, and the like. More than 95% alumina containing corundum is a high-quality refractory material with a wide range of uses. The chrome brick is mainly composed of chromium oxide, which is mainly made of chrome ore. The main crystalline phase is chromite. It has good corrosion resistance to steel slag, but has poor thermal shock resistance and low temperature deformation temperature. The chrome-magnesia bricks made of chrome ore and magnesia in different proportions have good thermal shock resistance and are mainly used as alkaline flat roof bricks. Carbonaceous refractory is another type of neutral refractory. According to the composition of carbonaceous raw materials and the mineral composition of the products, carbon bricks, graphite products and silicon carbide products. Carbon bricks are made of high-grade petroleum coke, tar and asphalt are used as binders, and fired at 1300 ° C under air. Graphite products (except natural graphite) are obtained by graphitizing carbonaceous materials in an electric furnace at 2500 to 2800 °C. The silicon carbide product is made of silicon carbide as a raw material, and a binder such as clay or silicon oxide is fired at 1350 to 1400 ° C, and silicon carbide-silica powder can also be made into a silicon nitride-silicon carbide product in an electric furnace under a nitrogen atmosphere. .

Carbonaceous products have low thermal expansion coefficient, high thermal conductivity, good thermal shock resistance, high temperature strength, no softening under long-term use at high temperatures, no corrosion by any acid and alkali, good salt resistance, and no The wetting of metal and slag is light and high quality. The disadvantage is that it is easily oxidized at high temperatures and should not be used in an oxidizing atmosphere. Carbonaceous products are widely used in high temperature furnace linings (bottom, hearth, lower part of the furnace, etc.) and lining of smelting non-ferrous metal furnaces. Graphite products can be used as reaction tanks and petrochemical autoclave linings. Silicon carbide and graphite products can also be used to make bismuth copper with gold and light alloys.