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›› 2007, Vol. 7 ›› Issue (5): 967-972.

• 过程与工艺 • 上一篇    下一篇

亚熔盐溶出一水硬铝石型铝土矿过程中赤泥的铝硅行为

王少娜,郑诗礼,张懿   

  1. 中国科学院过程工程研究所
  • 出版日期:2007-10-20 发布日期:2007-10-20

Behavior of Al and Si in Red Mud from Leaching Process of Diaspore Bauxite with NaOH Sub-molten Salt

WANG Shao-na,ZHENG Shi-li,ZHANG Yi   

  1. Institute of Process Engineering, Chinese Academy of Sciences
  • Online:2007-10-20 Published:2007-10-20

摘要: 对NaOH亚熔盐溶出一水硬铝石型铝土矿过程中赤泥的Al, Si行为进行了研究,通过实验研究了溶出过程的反应温度、碱矿比、添加CaO等主要因素对赤泥成分和物相结构的影响. 结果表明,在相同碱矿比下,温度越高越有利于Al2O3的溶出. 在碱矿比为2、反应温度为180℃、反应时间为2 h的条件下,一水硬铝石完全溶出,赤泥中硅主要以Na8Al6Si6O24(OH)2(H2O)2和Na9Al9Si15O48(H2O)27的钠铝硅酸盐形式存在. 亚熔盐溶出过程中添加CaO并不能抑制Si进入溶出液中,甚至会降低Al2O3的溶出率. 但添加CaO可以减少碱的损耗,适于处理中等品位的铝土矿.

关键词: 亚熔盐, 溶出, 一水硬铝石, 赤泥

Abstract: The behavior of Al and Si in red mud in the leaching process of diaspore bauxite with NaOH sub-molten salt was investigated. The effects of reaction temperature, mass ratio of alkali to ore and CaO addition on the behavior of diaspore bauxite in NaOH sub-molten salt were investigated by experiment. The results show that high temperature leads to the total leaching of diaspore bauxite. Silicon-containing ore is the most common impurity in bauxite. In the process of alumina production with NaOH sub-molten salt, almost all the Si in bauxite is transformed into aluminosilicate. AlOOH disappears in red mud under the conditions of the ratio of alkali to ore 2, leaching temperature 180℃ and leaching time 2 h. Al and Si coexist in the resulting red mud in the forms of Na8Al6Si6O24(OH)2(H2O)2 and Na9Al9Si15O48(H2O)27 after leaching. The addition of CaO in the leaching process does not prevent Si from entering liquid phase under the temperature of 180℃. The leaching rate of Al2O3 is reduced under the condition of CaO addition in the sub-molten salt process. But the addition of CaO can reduce the loss of NaOH, it is beneficial to the leaching of middle grade bauxite.

Key words: sub-molten salt, leaching, diaspore bauxite, red mud