Research on recycling rare earth concentration from rare earth wastewater

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%