选择性磷酸沉淀分离铬铁的新工艺

A new process for separation of chromium from iron by selective phosphate precipitation

  • 摘要: 针对酸性水溶液中铬铁分离难题,基于Fe3+还原预处理,提出选择性磷酸沉淀铬分离铬铁的方法。研究沉淀剂Na3PO4用量、溶液初始pH值、反应温度及保温时间等对铬铁分离的影响,所得较优工艺条件为:溶液初始pH值为2.0,按PO43-/Cr3+摩尔比0.375的量加入Na3PO4,90 ℃保温60 min。在上述条件下,铬沉淀率可达98.53%,铁沉淀率仅1.42%,分离效果理想。实验还证明,该方法适用于较宽的铁浓度范围,而且Cu2+、Zn2+、Ni2+及Cl-等杂质离子对选择性沉铬无明显干扰。该方法为含铬物料的铬分离提取提供了一条新的可选途径。

     

    Abstract: The selective phosphate precipitation process is proposed for the effective Cr/Fe separation in acidic solutions after the pretreatment of Fe3+ reduction. The effects of dosage of Na3PO4 as the precipitant, the initial pH, reaction temperature and time on Cr/Fe separation are experimentally studied. The optimal conditions are determined as follows: initial pH of 2.0, PO43-/Cr3+ molar ratio of 0.375, reaction temperature of 90 ℃, reaction time of 60 min. Under the above conditions, the precipitation of Cr is achieved as 98.53% while that of Fe is only 1.42%. This new process is proved to be applicable to a wide range of Fe concentration of the solutions and the impurities, such as Cu2+, Zn2+, Ni2+ and Cl- have no obvious effects on the selective precipitation of Cr, which provides a new alternative process for the separation and resourcelization of Cr from Cr-containing materials.

     

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