Calcined bauxite for refractory material

Calcined bauxite for refractory material

The chemical composition of bauxite is mainly Al2O3, SiO2, Fe2O3, TO2, accounting for about 95% of the total composition.

Al2O2 is the main chemical component of bauxite, and its occurrence state is mainly aluminum hydroxide, by aluminosilicate, which is clay minerals; in addition, it can also contain a small amount or trace amount in iron and titanium minerals. SiO2- generally exists as clay minerals, and rarely is free stone molybdenum.

Fe2O2 generally exists in the form of hematite in karst or sedimentary bauxite: the primary zone is often pyrite, less siderite, oolitic mud, and rarely magnetite, etc.; Belt (late weathering) and red seven-type bauxite are mainly goethite, others such as water hematite, water goethite and aluminum goethite, aluminum hematite, etc.

Rare. In addition, a small amount of iron often exists in diaspore, boehmite, gibbsite and corundum in a similar form.

The content of TiO2 in bauxite is usually 2%~4%, but there are also higher, which can reach 6%~12%, such as bauxite in southwestern Sichuan and India.

Both titanium and aluminum are inert elements in the process of parent salt weathering, so A/Ti often maintains a constant ratio in each mining area. In bauxite, the independent minerals of T element are mainly anatase and rutile, by brookite, leucite and ilmenite. There are also similar occurrences in aluminum minerals. In addition, it also occurs in other minerals in the form of gels.

S is a very harmful impurity in bauxite, and it generally exists in the form of pyrite. The pyrite content is higher in the acoustic zone of sedimentary or karst bauxite; the sulfur content in the oxidation zone or accumulation bauxite is lower, generally between 0.05% and 0.1.

Physical and chemical indicators of calcined bauxite

The use of calcined bauxite:

(1) Aluminum smelting industry. For, aviation, automobiles, electrical appliances, chemicals, daily necessities, etc.

(2) Precision casting. The bauxite clinker is processed into fine powder to make a mold and then precision cast. For medical, aerospace, communications, instrumentation, machinery and medical equipment sectors.

(3) For refractory products. High alumina bauxite clinker has a refractoriness of up to 1780℃, strong chemical stability and good physical properties.

(4) Aluminum silicate refractory fiber. It has the advantages of light weight, high temperature resistance, good thermal stability, low thermal conductivity, small heat capacity and mechanical vibration resistance. For steel, non-ferrous metallurgy, electronics, petroleum, chemical, aerospace, atomic energy, and other industries. It is to put high-alumina clinker into a high-temperature electric arc furnace with a melting temperature of about 2000-2200 ° C, and after high-temperature melting, high-pressure high-speed air or steam injection, and cooling, it becomes white "cotton" - aluminum silicate refractory fiber. It can be pressed into fiber blanket, board or woven into cloth to replace refractory bricks lining high temperature furnaces in smelting, chemical, glass and other industries. Firefighters can use fire-resistant fiber cloth to make clothes.

(5) Using magnesia and bauxite clinker as raw materials, adding appropriate binder, it is very effective for pouring the overall lining of the ladle.

(6) Manufacture of various compounds of alumina cement, abrasive materials, ceramic industry and chemical industry that can make aluminum.