从稀土废水中回收制备氧化稀土试验研究

    Research on recycling rare earth concentration from rare earth wastewater

    • 摘要: 稀土冶炼废水中含有一定浓度的稀土元素,如不加以回收,会造成稀土资源的浪费。为使回收稀土废水中的稀土,试验采用化学沉淀-萃取反萃-草酸精制的工艺回收废水中的稀土。化学沉淀试验表明,以氢氧化钠为沉淀剂,废水中稀土的沉淀率可达97.51%;沉淀经酸溶,水解除铁后进行稀土萃取试验,萃取级数2级,稀土元素的萃取率为97.33%;萃取后的稀土富集有机相经3级反萃,草酸精制后获得氧化稀土产物。整个工艺流程中稀土总回收率为90.93%。

       

      Abstract: There are certain concentrations of rare earth elements in rare earth waste water, and it would be a waste of rare earth resources if the elements were not being recycled. In purpose of recycling rare earth in waste water, a process, which includes chemical precipitation, extraction and reextraction, oxalic acid refining, is used to recycle rare earth in waste water. Test results of chemical precipitation indicates that the precipitation ratio of rare earth in waste water can reach up to 97.51% when the pH value of waste water is 10 and the precipitation time is 15 minutes. Tests of rare earth extraction is carried out after the sediment were soluted by acid and removed ferric ion. The extraction ratio of rare earth is 97.33% on the comprehensive conditions of 50% of extraction agent concentration, 1:1 of phase ratio,20 minutes of extraction time and 2 extraction stages. Concentrations of rare earth oxides is acquired from concentrated organic phase of rare earth through 3 stages of reextraction and oxalic acid refining. The reextraction ratio is 96.94% while the rare earth recovery of oxalic acid refining process is 99.53%. The gross recovery of rare earth in the whole technological process is 90.93%

       

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