The sulfur in high-sulfur bauxite not only pollutes the environment but also harms alumina production. This study investigated the removal of sulfur from high-sulfur bauxite by adding Zn or ZnO during the Bayer process. The results showed that the different valence sulfur (S2−, S2O32−, SO32−, and SO42−) in sodium aluminate solution can be effectively removed by adding Zn during the digestion process. Adding ZnO removes the S2− in liquor, but the other sulfur compounds (S2O32−, SO32−, and SO42−) are not affected. The mechanism of sulfur removal has been elucidated, where the S2O32−, SO32−, and SO42− are first reduced to S2−, and after adding Zn, the S2− enters into red mud in the form of ZnS. The ZnO then reacts with S2− to generate the ZnS that enters into red mud. Thus, this is a new and effective method of sulfur removal by adding Zn during the digestion process. The results shed light on the removal of sulfur from high-sulfur bauxite during alumina production.

中文翻译：

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高硫铝土矿的脱硫

高硫铝土矿中的硫不仅会污染环境，还会危害氧化铝的生产。本研究调查了在拜耳法过程中通过添加 Zn 或 ZnO 从高硫铝土矿中去除硫。结果表明，在消化过程中加入Zn可以有效去除铝酸钠溶液中不同价态的硫（S2-、S2O32-、SO32-和SO42-）。添加 ZnO 可去除溶液中的 S2-，但其他含硫化合物（S2O32-、SO32- 和 SO42-）不受影响。阐明了脱硫机理，其中S2O32-、SO32-和SO42-首先被还原为S2-，加入Zn后，S2-以ZnS的形式进入赤泥。然后 ZnO 与 S2− 反应生成进入赤泥的 ZnS。因此，这是一种在消化过程中添加锌的新的有效脱硫方法。结果揭示了在氧化铝生产过程中从高硫铝土矿中去除硫的问题。