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›› 2008, Vol. 8 ›› Issue (6): 1148-1152.

• 过程与工艺 • 上一篇    下一篇

NaOH亚熔盐法处理拜尔法赤泥的铝硅行为

孙旺 郑诗礼 张亦飞 徐红彬 张懿   

  1. 中国科学院过程工程研究所绿色过程与工程院重点实验室 中国科学院过程工程研究所 中国科学院过程工程研究所 中国科学院过程工程研究所绿色过程与工程重点实验室 中国科学院过程工程研究所
  • 收稿日期:2008-08-01 修回日期:2008-10-06 出版日期:2008-12-20 发布日期:2008-12-20
  • 通讯作者: 郑诗礼

Behavior of Al and Si in Bayer Red Mud Processed by NaOH Sub-molten Salt

SUN Wang ZHENG Shi-li ZHANG Yi-fei XU Hong-bin ZHANG Yi   

  1. Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering,Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences
  • Received:2008-08-01 Revised:2008-10-06 Online:2008-12-20 Published:2008-12-20
  • Contact: ZHENG Shi-li

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摘要： 针对拜尔法赤泥铝/硅比偏高的问题，对NaOH亚熔盐法处理拜耳法赤泥过程中的Al, Si行为进行了研究. 考察了溶出温度、碱/泥比、添加CaO等主要因素对终赤泥化学成分和物相结构的影响. 结果表明，溶出温度高、碱/泥比大有利于Al2O3的回收，相应的终赤泥的铝/硅比较低. 在碱/泥比6、溶出温度230℃、时间2 h的条件下，氧化铝回收率可达79.22%，终赤泥的铝/硅比可降到0.39，终赤泥中的硅主要以NaCaHSiO4和Ca3(Fe0.87Al0.13)2(SiO4)1.65(OH)5.4形式存在. 在处理CaO/SiO2>1.2的拜尔法赤泥时继续添加CaO并不能继续提高Al2O3的回收率.

关键词: 亚熔盐, 拜耳法, 赤泥, 氧化铝, 铝, 硅

Abstract: Based on the problem of higher Al2O3/SiO2 (A/S) of Bayer red mud, the separation of Al and Si in red mud from Bayer process in digestion with NaOH sub-molten salt was investigated. The effects of digestion temperature, mass ratio of alkali to red mud from Bayer process and CaO addition on the behavior of red mud in the salt were experimentally investigated. The results show that high temperature and mass ratio of alkali to red mud lead to more alumina into the aqueous phase and the decrease of A/S in brown mud. The recovery rate of Al2O3 can reach 79.22% and A/S in the brown mud is decreased to 0.39 under the conditions of mass ratio of alkali to red mud at 6, digestion temperature at 230℃, and digestion time for 2 h. Further study shows that Si exists in the form of NaCaHSiO4 and Ca3(Al0.13Fe0.87)2(SiO4)1.65(OH)5.4. The recovery rate can not be further raised under the condition of CaO addition in sub-molten salt process when the molar ratio of CaO to SiO2 over 1.2 in the original red mud.

Key words: sub-molten salt, Bayer process, red mud, alumina, aluminium, silicon

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