胶质气体泡沫浮选法脱除磷酸二氢钠中Fe^(3+)研究

Study on removal of Fe^(3+) from sodium dihydrogen phosphate by colloidal gas aphrons

用湿法磷酸来生产工业级磷酸二氢钠(NaH_2PO_4)时,由于湿法磷酸中含有大量杂质,如金属阳离子Fe^(3+)、Mg^(2+)、Al^(3+)等,为了制备合格产品,必须采用适当的分离除杂手段除去这些离子。本文提出采用胶质气体泡沫(CGA)对其进行除Fe^(3+)杂质。以十二烷基苯磺酸钠(SDBS)作为表面活性剂,在5000r·min-1的转速下生成胶质气体泡沫(CGA)。然后,将其通入浮选柱中。静置一段时间之后,进行气浮分离。本文主要考察静置时间、Fe^(3+)浓度以及浮选时间对去除率的影响。实验结果表明,Fe^(3+)的去除率随Fe^(3+)的浓度以及静置时间的增大而降低,而随浮选时间的增大而增大。实验结果表明,在适宜工艺条件下,经过三级萃取Fe^(3+)去除率可达95%以上。

Wet-proeess phosphoric acid （WPA） is gradually paid attention to in recent years. However, there are some undesirable impurities （Fe^3＋ Al^3-, Mg2＋） in WPA, which will degrade the quality of sodium dihydrogen phosphate （NaH2PO4） products. To get the superior grade NaH2PO4, the WPA should be purified. In this paper, colloidal gas aphrons is applied to remove Fe^3＋, in this experiment, CGA is created by stirring sodium dodeeylbenzene sulfonate surfactant solution at a high speed of 5000r·min^-1. Then, CGA suspensions are injected in the flotation column. CGA suspensions and NaH2PO4 solution are separated by flotation after stewing a while. Meanwhile, to study the advantages of the CGA flotation process, the major influencing factors on the extraction efficiencies of Fe^3＋ is investigated, and the optimal influencing factors for removal of Fe^3＋ with CGAs is presented. The results show that the removal ratio of more than 95% can be obtained by three cross-flow flotation under appropriate conditions.