铝土矿焙烧脱硅新工艺及机理研究

Study on New Technology of Banxite Desilication by Roasting and Its Mechanism

介绍了中、低铝硅比的一水硬铝石 -高岭石型铝土矿 ,回转窑焙烧脱硅试验的情况。其试验结果表明 ,在焙烧温度 10 5 0～ 110 0℃、焙烧时间 15～ 2 0min时 ,脱硅率达到 5 5 6 1% ,精矿铝硅比 9 92。X射线衍射分析结果表明 ,焙烧只能使高岭石中的硅发生热分解 ,产生非晶态的SiO2 ,而矿石中原来存在的α -石英会向非晶态转化 ;在焙烧矿碱浸溶出过程中 ,非晶态的SiO2 溶于碱液被脱除 ,而α -石英保持不变。

Tests on the desilication of monohydrate and kaolinite type bauxite ores that have medium and low ratios of aluminium to silicon (Al/Si) by roasting in rotary kiln are presented.The test results show that at a roasting temperature of 1050～1100℃ and a roasting time of 15～20min, the desilication rate can reach 55.61% and the Als ratio of the concentrate 9.92. XRD analysis results indicate that only the silica in kaolinite can be transferred into noncrystalline one by roasting while the α-silica originally existing in the ore won't. In the leaching of the roasted ore, the noncrystalline silica which can is dissolved in NaOH solution can be removed while α-silica can't be.