Introduction of Calcine bauxite rotary kiln 

Bauxite rotary kiln, also called alumina rotary kiln is a kind of rotary kiln, we can see from the name, the rotary kiln is mainly for in development of alumina rotary kiln, which is mainly composed of a rotary part, supporting part, transmission device, kiln hood, kiln head tail sealing, burning device and etc. composition. Kiln supporting board and a kiln tail material returning scoop the block casting, convenient installation, with high heat resistance and corrosion resistance, wear resistance, kiln head cold air sleeve through air cooling, can, to the mouth of the kiln kiln shell and guard plate of uniform cooling the safer and more reliable. The kiln head cover adopts a large volume method, and the structure of the kiln door is opened, so that the air flow is more stable. Kiln head, a kiln tail seal using radial friction maze, scales double sealing form, has the advantages of simple structure, convenient maintenance is at present domestic most advanced seal form. Swirl type four channel coal powder burner with fuel injection ignition device used in combustion device.

Features of Calcine bauxite rotary kiln

Calcine bauxite rotary kilnis used for calcinating high standard cement in cement factories, but also widely used in metallurgy, construction and chemical industry.

The rotary kiln produced by our factory has strong structure, smooth operation, and high quality products. Besides, we provide our customers with advanced and efficient shaft preheater and five stage cyclone preheater.

The rotary kiln calcination process of bauxite

The rotary kiln Calcined Bauxite changes can be divided into three sections: the decomposition stage, the two stage of mullite petrochemical  and crystallization sintering stage.

1. Decomposition stage：400 ℃ -1200 ℃ temperature range is bauxite decomposition stage.Diaspore and kaolinite in bauxite at 400℃ start dehydration, 450-600 ℃ intense reaction, 700-800 ℃ completed.Gibbsite under high temperature gradually transformed corundum, kaolinite and dehydrated into metakaolin, more than 950 ℃ into mullite and amorphous SiO2,which is converted to cristobalite at high temperatures.
2. Mullite petrochemical phase: Above 1200 ℃, corundum and SiO2 continue to react to form mullite, is known as the secondary mullite:
   3AI2O3 + 2SiO2 → (≥1200 ℃) → 3AI2O3 + 2SiO2 (secondary mullite)
   In the secondary mullite petrochemical, it occurs about 10% volume expansion,while below the 1300-1400 ℃,Fe2O3, TiO2 of bauxite, and other impurities with Al2O3, SiO2 can form reaction liquid,liquid phase formation is contributed to secondary mullite formation,but also makes preparation for the sintering of barite.
3. Barite sintering stage：With the completion of secondary mullite petrochemical,Barite sintering rapid action is beginning.Above 1400-1500 ℃,due to the liquid phase, corundum and mullite crystals is growing,when 1500 ℃ is about 10μm, 1700 ℃ respectively 60μm and 90μm.The main factors affecting the sintered bauxite are secondary mullite petrochemical phase,liquid and structure of bauxite.Global mined bauxite,with more than 85% by using rotary kiln to produce alumina,followed by the production of aluminum metal.10% is used in the production of alumina using non-metallic, and the remaining for non-metallurgical bauxite applications.

Model	Kiln size			Speed（r/min）	Power（kw）	Capacity（t/d）	Weight（t）	Note
	Diameter（m）	Length（m）	Slope（%）
1.5*36	1.5	36	3.5	0.3-3	22	15-20	48
1.8*45	1.8	45	3.5	0.3-3	30	20-30	83
2*50	2	50	3.5	0.3-3	37	30-50	118
2.2*55	2.2	55	3.5	0.3-3	45	50-70	143
2.5*60	2.5	60	3.5	0.3-3	55	70-100	199
2.5*48	2.5	48	3.5	0.3-3	45	130-150	159	4 pusher device preheat
3*70	3	70	3.5	0.3-3	90	200-250	341
3.2*52	3.2	52	3.5	0.3-3	125	280-300	295	6 pusher device preheat
3.3*90	3.3	90	3.5	0.3-3	220	300-330	549
3.6*55	3.6	55	3.5	0.3-3	315	350-400	409	8 pusher device preheat
4*90	4	90	3.5	0.3-3	420	450-500	798
4*60	4	60	3.5	0.3-3	380	560-600	532	10 pusher device preheat
4.8*70	4.8	70	3.5	0.3-3	630	900-1000	944	12 pusher device preheat