Views: 85 Author: Bella Publish Time: 2018-06-28 Origin: SEPPE Technologies
Calcined bauxite is produced by sintering/calcining of low iron, low alkali containing raw bauxites at temperatures of 1600 - 1800 degree Celsius. This removes moisture thereby increasing the alumina content. Compared to an alumina content of about 57 % to 58 % in raw Bauxite, Calcined Bauxite has an alumina content of 82 % to 86 %. The heating is carried out in rotary kilns.In this calcination process the high refractory mineral phases corundum and mullite are formed. Refractory grade bauxite has high refractoriness, good mechanical strength and moderate slag resistance. Therefore calcined bauxite is one of the most important raw materials for the production of shaped and unshaped refractories for the steel industry, foundries, glass and cement plants.
Refractory grade bauxites have a high alumina content and a very low alkali content with low impurities (iron oxide and titania specifically), ensuring stable temperature strength.Refractory applications remain the premiere non-metal market for calcined bauxite which is mixed with binders and pressed, extruded, cast and shaped into a variety of forms that are then dried and transfered to kilns for firing. The calcined refractory grade bauxite is also used in unfired monolithic refractories.