(中南工业大学 矿物工程系， 长沙 410083)
摘 要: 在烧结杯上模拟带式焙烧机进行了铝土矿的焙烧脱硅试验。结果表明： 采用带式焙烧机焙烧铝土矿是可行的。 获得的焙烧工艺条件为： 矿石粒度0～5 mm， 焦粉用量3.4%， 混合料水分7.5%， 950 ℃点火1 min， 800 ℃保温2 min， 点火负压3 kPa， 焙烧负压7 kPa。 采用苛性碱溶出脱硅， 焙烧矿脱硅率可达43.45%， 精矿A/S＝8.31。X射线衍射分析表明： 焙烧过程中高岭石发生热分解产生的非晶态SiO2，经碱处理后溶于NaOH而被脱除。 高压溶出试验表明： 脱硅铝精矿中Al2O3的溶出率比原矿高。
关键字: 一水硬铝石型铝土矿； 化学选矿； 脱硅
（Department of Mineral Engineering， Central South University of Technology，Changsha 410083， P.R.China）
Abstract:The roasting process of the desilication from diasporic bauxite was studied on sintering cup simulating grate machine. It is shown that using grate machine as the roasting apparatus of bauxite is practicable. The optimum roasting parameters for grate machine are: size of ore 0～5 mm, coke (size <1 mm and coated on mixer surface) consumption 3.4%, ignition temperature 950 ℃, ignition time 1 min, thermal insulation at 800 ℃ for 2 min, water content 7.5%, negative pressure of ignition 3 kPa, negative pressure of roasting 7 kPa, dosage of F additive 0.6%. By alkalileaching, rate of desilication 43.45% and A/S of the concentrate 8.31, were obtained. By means of Xray diffraction analysis, the following conclusions can be made: only Si existing in kaolinite can be changed into noncrystalline SiO2, during the digestion, this kind of SiO2 is dissolved in NaOH solution, but α SiO2 does not dissolve, so it is not contributive to desilication. The digestion of the concentrate by Bayer process also shows that the digestion ratio of Al2O3 of the concentrate is higher than that of the raw ore.
Key words: diasporic bauxite； chemical processing； desilication
