Performance of separating rare earth enrichment from aqueous solution by flat ceramic membrane process and pollution control strategy

Abstract

At present, in the mining process of ionic rare earths, the separation of rare earth element (REEt) from aqueous solution still relies on natural sedimentation, which has the disadvantage of low efficiency. Additionally, there will be a significant amount of rare earth ions (∼ 30 ppm) remaining in the supernatant. In this work, the use of flat ceramic membranes to separate REEt from aqueous solution is innovatively proposed. Firstly, the performance of REEt separation by flat ceramic membrane process was determined. It was found that the flat ceramic membrane process had good interception performance for REEt separation, and the concentration of rare earth ions in the supernatant was close to 0 ppm. Then, the impacts of different operating conditions (including operating time, backwash duration and concentration times) on the membrane fouling process were investigated. It was demonstrated that the shorter the operating time, the less the degree of membrane fouling. The operation of back washing was greatly beneficial to renew membrane flow. The change of reversible pollution resistance was calculated, the process of membrane pollution was analyzed by four pollution models, and the pollution mechanism was discussed in detail. Furthermore, the recovery of membrane flow after chemical cleaning and non-agent cleaning, and the changes in reversible fouling resistance under different concentration multiples were also studied. It is proved that the immersed flat ceramic membrane has the characteristics of low membrane fouling, high solid–liquid separation efficiency, and good stability for the separation and enrichment of rare earth particles, which shows great potential in industrial applications.