(中南工業(yè)大學 礦物工程系， 長沙 410083)
摘 要: 在燒結杯上模擬帶式焙燒機進行了鋁土礦的焙燒脫硅試驗。結果表明： 采用帶式焙燒機焙燒鋁土礦是可行的。 獲得的焙燒工藝條件為： 礦石粒度0～5 mm， 焦粉用量3.4%， 混合料水分7.5%， 950 ℃點火1 min， 800 ℃保溫2 min， 點火負壓3 kPa， 焙燒負壓7 kPa。 采用苛性堿溶出脫硅， 焙燒礦脫硅率可達43.45%， 精礦A/S＝8.31。X射線衍射分析表明： 焙燒過程中高嶺石發(fā)生熱分解產(chǎn)生的非晶態(tài)SiO2，經(jīng)堿處理后溶于NaOH而被脫除。 高壓溶出試驗表明： 脫硅鋁精礦中Al2O3的溶出率比原礦高。
關鍵字: 一水硬鋁石型鋁土礦； 化學選礦； 脫硅
（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
