富云母高岭石铝土矿拜耳法溶出性能研究

Digestion Performance of Mica-and-Kaolinite-Rich Bauxite by Bayer Process

富云母高岭石铝土矿具有铝高、硅高和铝硅比低的特点,为有效开发利用该类型铝土矿,了解拜耳法溶出氧化铝工艺的适应性,获得适宜的溶出条件并提高溶出率,采用高压盐浴溶出试验研究溶出温度、溶出时间、循环母液苛性碱浓度、石灰添加量、矿石粒度和配料分子比对氧化铝溶出性能的影响。结果表明:该铝土矿适合采用拜耳法溶出,适宜溶出条件为:溶出温度260~280℃、溶出时间60min以上、循环母液苛性碱浓度220~240g/L、石灰添加量9%、矿石粒度0.28mm、配料分子比1.35~1.45。在此条件下,氧化铝实际溶出率达72%以上,相对溶出率达96%~98%。

Mica-and-kaolinite-rich bauxite has characteristics of high alumina and silica content,and low alumina-silica ratio.In order to effectively develop and utilize this type of bauxite,understand adaptability of Bayer process for digesting alumina,obtain appropriate digestion conditions and improve digestion rate,high pressure salt-bath digestion experiments were conducted to study effects of temperature,time,caustic concentration of circulating mother liquor,lime addition,ore size and ingredient ratio on digestion properties of alumina.The results show that this type of bauxite is suitable for Bayer process;actual digestion rate of alumina is 72%above and relative digestion rate is 96%-98%under the digestion conditions including digestion temperature of 260-280℃,digestion time of 60 min above,caustic concentration of circulating mother liquor of 220-240 g?L,lime addition of 9%,ore size of 0.28 mm,and ingredient ratio of 1.35-1.45.