Separation And Extraction Of Associated Rare Earth From Phosphate Rock By Liquid Membrane Separation Method

Emulsion liquid membrane?ELM? technology has several key advantages in use such as: high efficiency, high selectivity, lowcost and energy saving. Based on these advantages, ELM technology was used for extracting rare earth ions(RE³⁺) from phosphate leach solution in our research. The rare earths was extracted from the solution by the way of W/O/W emulsion liquid membrane technique which contains the flow carrier. Various factors of this process were examined during extraction of the rare earths. It was determined that the efficient liquid membrane and technological conditions continually increased the extraction efficiency. The research of the ELM stability using the AZLC system emulsion with T154 as the surfactant and AZLC as carrier.Various emulsion system with P204?P507?P204-C?P204-A?P507-C?P507-A and AZLC as carriers respectively were used for extracting rare earth from the rare earth solution. By studying the effect of different acidity of the external phase and different R_ew?the volume ratio of emulsion phase to external phase? on extraction rate of RE³⁺, and choosing AZLC as carrier was applied to extract the RE³⁺ from phosphate leach solution.Emulsion liquid membrane method was used to make AZLC system emulsion.The effect of different parameters such as type and concentration of surfactant and the concentration of carrier, hydrochloric acid concentration, organic to internal phase volume ratio(R_oi), emulsion to external phase volume ratio(R_ew) on extraction of RE³⁺ has been investigated on the phosphate leach solution with high acidity(p H^-1.66) as external phase, and the optimum emulsion system were determined to be: 6%?V/V? AZLC, 4% T154, 90% sulfonated kerosene as organic phase, the internal phase is 6 mol L^-1 HCl, the volume ratio of organic to internal phase is 1:1, stirring speed of making emulsion is 4000r/min, stirring time of making emulsion is 20 min. When extracting, the emulsion to external phase volume ratio is 1:10, and the extraction rate of RE³⁺ from phosphate leach solution can reach 93.53% then. In addition, the emulsion to external phase volume ratio is 1:100, and the extraction rate of RE³⁺ fromphosphate leach solution can still reach 87.47%.Method of combining the effect of the stability of emulsion and extracting of liquid membrane was used to make emulsion. By studying the effect of the concentration of surfactant and internal phase, organic to internal phase volume ratio on the stability of the emulsion membrane, the condition of making emulsion under the AZLC emulsion membrane system were determined to be: 4%?V/V? T154, the volume ratio of organic to internal phase is 1:1, the internal phase is 6 mol L^-1 HCl.The stability of different type of carrier of emulsion liquid membrane was investigated, and the results showed that: Amine extractants > Neutral phosphonic extractants > Phosphine acid extractants.