| Sinte-roasting between coal and Alumina or coal and bauxite were researched in detail in this paper. This is one part of the process study of preparation Aluminium from bauxite direct reduction by halide at the condition of vacuum, the subject study is patronized by nature fund of YunNan province.By consulting and indexing related data, and carrying through generalization analysis, the feasibility process was confirmed, this technics probably made cost reduction of Aluminium; but, at the process of the experiment found that material eject so badly that the reaction degree can not be observed, therefore, the paper pay more attention to sinter-roasting of materials, and get experimental feeds that meet the challenge at last, providing fundamental basis and experiment for further studies on the assay. The experiment material are : coal (in order to provide carbon which needed in the reduction process), Alumina and Bauxite. At first, the process of sinter-roasting between coal and Alumina was studied, through series of experiment found that optimally condition of sinter-roasting between coal and Alumina is : the mass ration of coal with Alumina is 8:3;the sinter temperature should control at about 450C; holding time is 30 minutes, the addition of water is about 1/(9~10) of total mass, only in this way, can assure that material both commendably press forming and keep mechanical strength, if water content exceed, material's mechanical strength become more weak. Afterwards, according to the optimally condition of sinter-roasting between coal and Alumina, emphasis on sinter-roasting process between coal and Bauxite, from reaction coefficient and fixed carbon content in coal and Oxidate content in Bauxite, figure out that coal and Bauxite's mixture ratio which needed in the reaction was 71.85:100, however, at the experiment can found that if to the theoretical calculation result make up the charge, the coal and Bauxite basically can not close-burning. Thereby, adjust the addition of coal at the material, by adding coal content found that when the mass ratio at coal and Bauxite up to( 1 ~ 1.5): 1, can get preferable close-burning efficiency sintered material; at the mean time, excessive coal in the material can assure that oxide were completely reduced at the reduction reaction, the reaction will be exhaustive completion. The sinter temperature should control at about 600C; holding time is 30 minutes, at aboveconditions, the sinter-roasting of material's mechanical strength is preferable. Another casecan also found at the experiment, when the addition of water is about 1/(9~10) of total mass is adequate. The volatile component at the cause of Bauxite and coal sinter-roasting volatile rate's alteration differ from that of Alumina and Coal, when heat up to 20 minutes and temperature is about 200C, the material's volatile rate is maximal, with the temperature increasing the volatile rate also changed, till heating time maintain about 60 minutes, and temperature up to 600C, volatile component have completely volatilized, the residual pressure at vacuum firing furnace keep unchangeably, at the same time, the water in the material also volatilized completely , material's percent of void is at the most, and mechanical strength is preferable.This paper began with theoretics of metallurgy of aluminium, retrospect the history of metallurgy of aluminium, intensive introduce manufacturing methods of alumina from Bauxite, such as, Bayer process, sintering method, tandem process, multiple process and mixing process, aluminium is made from Alumina electrolysis process also introduced in detail; theoretics of metallurgy of aluminium and material sinter-roasting were expounded in this paper, through experiment, high mechanical strength, high percent of void and excessive fixed carbon content material have got. |
PDF Full Text Request