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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～ 5mm ,焦粉用量 3.4% ,混合料水分 7.5% ,950℃点火 1min ,80 0℃保温 2min ,点火负压 3kPa ,焙烧负压 7kPa。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Al2 O3的溶出率比原矿高。
Baking test of bauxite roasting was carried out in the simulated cup-roaster on the sintering cup. The results show that it is feasible to roast bauxite with a belt roaster. The obtained roasting conditions were as follows: the ore size was 0-5 mm, the coke powder content was 3.4%, the mixture moisture content was 7.5%, 950 ℃ ignition 1min, 800 ℃ insulation 2min, ignition negative pressure 3kPa, roasting negative pressure 7kPa. Using caustic stripping and desilication, the desilication rate of calcined ore can reach 43.45%, concentrate A / S = 8.31. X-ray diffraction analysis shows that amorphous SiO2 produced by thermal decomposition of kaolinite during calcination is dissolved in NaOH and removed by alkali treatment. High-pressure dissolution test showed that the dissolution rate of Al 2 O 3 in desiliconized aluminum concentrate is higher than that of ore.