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Alumina bauxite

Alumina(aluminous soil; bauxite) also known as alumina and bauxite, main component is aluminum oxide, hydrated alumina system containing impurities, is a kind of clay mineral.
Description

Aluminum Bauxite Introduction


Alumina(aluminous soil; bauxite) also known as alumina and bauxite, main component is aluminum oxide, hydrated alumina system containing impurities, is a kind of clay mineral. White or grey white, due to iron and brownish yellow or light red. Density of 3.9 ~ 4g/cm3, hardness 1 ~ 3, opaque, crisp, very difficult to melt. Insoluble in water, soluble in sulfuric acid, sodium hydroxide solution, mainly used in aluminum smelting, making refractory materials.

Bauxiterefractories industry called usually refers to Al2O3>=48%, and Calcined Bauxite Containing Low Fe2O3, high alumina bauxite is calcined bauxite. Clinker as pale yellow and dark grey, it is mainly used for high aluminum refractory material, also can be used to fabricate fused brown corundum.


Alumina bauxite classification

1, raw bauxite, alumina raw ore (natural sedimentary rock class).

To have 2, calcined bauxite, alumina after high temperature calcination (1200 ~ 1700 ℃) is called the calcined bauxite.

High bauxite clinker is according to the content of AL2O3 and Fe2O3, TiO2, Ca + Mg O O, K2O + Na2O and other impurity content and clinker indicators such as volume density and bibulous to classification.

Calcined bauxite by calcining kiln divided into:

1, the SHAFT furnace calcined BAUXITE (SHAFT up BAUXITE);

2, converter calcined BAUXITE (ROTARY up BAUXITE);

3, down-draft KILN BAUXITE (ROUND up BAUXITE).

Calcined bauxite according to different purposes as:

1, refractory grade bauxite;

2, grinding grade bauxite;

3, welding grade bauxite.




Changes in physicochemical properties of bauxite after calcination



1,from the originalgray, dark gray appearance, gray yellow, gray, red, yellow and other colors, white, beige, into a brown red, blue, and blue as the aluminium content increased and deepened. The original earthy luster to corundum shiny or oily luster, sometimes appear on the surface of mild melt stone or crack;


2, alumina content was increased by 11 ~ 13%, other impurities increase the amount of micro;


3, volume 23%;


4, loss of about 14.5%;


5, by a water-based aluminum stone or a water al kaolinite type, into artificial corundum, mullite and a small amount of glass phase;


6, the hardness from the original 1 to 3 increased to more than 8;


7, the volume density from about 2.5g/cm3 increased to 2.8 ~ 3g/cm3 above;


8, the crystal water, water, water overflow structure attached;


9, the structure by the sparse, loose, soft into dense and hard;


10, water absorption decrease; alkaline slag resistance, resistance to enhance;


12, increase the intensity of;


13, permeability reduction;


14, the gasification rate reduction;


15, volatile component, easy combustion components, rustic flavor completely disappeared;


16, fire resistance up to 1780 ℃.



Alumina bauxite use


1, aluminium industry.Used for defense, aerospace, automotive, electrical, chemical industry, daily necessities, etc.

2, the precision casting.Alumina clinker made after mold precision casting processed into fine powder.Used in military industry, aerospace, communications, instrumentation, machinery and medical equipment department.

3, used for refractory products.High bauxite clinker as high as 1780 ℃ refractoriness, chemical stability strong, and good physical properties.

4, aluminum silicate refractory fiber.With light weight, high temperature resistance, good thermal stability, low thermal conductivity, heat capacity is small and the advantages of resistance to mechanical shock.Used in iron and steel, nonferrous metallurgy, oil, chemical space of atomic energy, defense and other industries.

5, magnesia and bauxite clinker as raw material, adding proper binder, used for pouring ladle whole ladle lining has particularly good effects.

6, manufacture alumina cement, abrasive materials, ceramic industry and the various compounds can be aluminum.