The chemical composition of bauxite is mainly Al2O3, SiO2, Fe2O3, TO2, accounting for about 95% of the total composition, and the secondary components are CaO, MgO, K2O, Na20, S, MnO2 organic matter and trace components Ga, Ge, etc.
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
Project |
Al2O3% |
Fe2O3% |
TiO2% |
CaO+MgO% |
K2O+Na2O% |
Bulk density(g/cm3) |
water absorption |
GL-90 |
≥89.5 |
≤1.5 |
≤4.0 |
≤0.35 |
≤0.35 |
≥3.35 |
≤2.5 |
GL-88A |
≥87.5 |
≤1.6 |
≤4.0 |
≤0.4 |
≤0.4 |
≥3.20 |
≤3.0 |
GL-88B |
≥87.5 |
≤2.0 |
≤4.0 |
≤0.4 |
≤0.4 |
≥3.25 |
≤3.0 |
GL-85A |
≥85 |
≤1.8 |
≤4.0 |
≤0.4 |
≤0.4 |
≥3.10 |
≤3.0 |
GL-85B |
≥85 |
≤2.0 |
≤4.5 |
≤0.4 |
≤0.4 |
≥2.90 |
≤5.0 |
GL-80 |
>80 |
≤2.0 |
≤4.0 |
≤0.5 |
≤0.5 |
≥2.90 |
≤5.0 |
GL-70 |
70~80 |
≤2.0 |
- |
≤0.6 |
≤0.6 |
≥2.75 |
≤5.0 |
GL-60 |
60~70 |
≤2.0 |
- |
≤0.6 |
≤0.6 |
≥2.65 |
≤5.0 |
GL-50 |
50~60 |
≤2.5 |
- |
≤0.6 |
≤0.6 |
≥2.55 |
≤5.0 |
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.
In recent years, bauxite powder and bauxite have been widely used in common cast steel coatings and cast iron coatings due to their high fire resistance, good chemical stability, small expansion coefficient, rich source and low price.
The refractory ramming material is prepared from a high proportion of granular and powdery materials and a very low proportion of binders and other components, even all of which are composed of granules and powders, and are subject to strong ramming. Bulk materials for construction.
Refractory wet mud used to block the iron outlet can be divided into two categories: water cannon mud and waterless gun mud. On large and medium -sized blast furnaces on high top pressure and high degree of smelting.
Silicon carbide castables mainly use 98 silicon carbide as the main raw material, add water reducing agent and micropowder, and use pure calcium aluminate cement as binder to make amorphous refractory materials. Cupola and other high temperature materials to be recorded.
Refractory carstables for ladles is made of high-purity fused corundum as the main material, high-purity spinel is added to the matrix, and an appropriate amount of binder and admixture (dispersant, water reducing agent) are added.
Anti stripping high alumina bricks are referred to as anti-stripping bricks or anti-stripping refractory bricks. Anti-stripping high-alumina bricks are widely used in my country's new dry process kiln, Libore kiln and wet process kiln, including kiln door cover, rising flue, cooling zone, decomposition zone, safety belt, transition zone, coolant rear Walls and side walls and beams with curved ceilings.
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Fireclay bricksis suitable for supporting hot blast stoves of large, medium and small blast furnaces