Experimental Study On New Process Of Appropriate Reduction-High Efficiency Dressing For High-iron Gibbsite

With the rapid development of steel and alumina industry, the lacking iron ore and aluminum source have been important bottlenecks of steel and alumina industry respectively. As a gibbsite being rich in iron, the high-iron gibbsite spreads over Guangxi, Fujian, Hainan and Taiwai and so on. The national reserve is more than1.5billion tons, only Guangxi has about more than200million tons. As for the comprehensive utilization of high-iron-gibbsite, many researches have been carried out, and several treatments have been presented successively including the flotation of Al and Fe, Al first then Fe and first Fe then Al. Owing to the disseminated agglutination and paragenesis of Fe and Al in high-iron gibbsite, dressing Fe or Al from high-iron gibbsite is extremely difficulty. So far, the high-iron-gibbsite still hasn’t been unutilized efficiently.Aiming at iron ore and aluminum source’s supply considering the current research situation, a new process of appropriate reduction-high efficiency dressing for high-iron gibbsite is given in this study. The chemical and phase composition, mineral distributing properties and roasting performance are investigated. Basing on characteristics analysis of raw material, the experimental study scheme of the appropriate reduction-high efficiency dressing technology is established. Through this study, the influence rule of the processing parameters, including the magnetic field strength, temperature and time of reduction, carbon ratio, particle size of bauxite, on process indexes are all considered. Several conclusions are obtained as follows:(1) The high-iron-gibbsite is made up of gibbsite, goethite, hematite, pyrite and quartz, etc. Because of complicated dissemination in minerals, agglutination among iron, aluminum and silicium minerals, fine particles, it is difficult to realize Fe-Al separation by conventional methods. (2) The high efficient Fe-Al separation in high-iron-gibbsite can be achieved by this new technology of appropriate reduction-high efficiency dressing. When the carbon ratio is2.0, reduction temperature is1400℃, reduction time is controlled of180min, and the magnetic field strength is selected at40KA/m, the new process indexes are given as follows:the grade of dressing product is78.23%, the metallization is achieved97.56%, the yield of iron also reaches89.24%, besides the grade and yield of alumina is53.23%and86.09%separately in tailings.(3) The optimized parameters are given, such as the carbon ratio is at the range of from1.5to2.5, the temperature is set between1440℃and1450℃, the time is no less than120min, and the biggest particle of bauxite is between2.00mm and3.00mm.(3) The product of dressing is the iron powder with high metallization, through the further disposition, which can be used in steel production. The tailings of dressing are high grade sources containing alumina, which can be used as superior raw material in alumina industry.