The growing industrial application of rare earth metals led to great interest in the new technologies for the recycling and recovery of REEs from diverse sources. This work reviews the various methods for the recycling of spent fluorescent lamps. The spent fluorescent lamps are potential source of important rare earth elements (REEs) such as: yttrium, terbium, europium, lanthanum and cerium. The characteristics of REEs properties and construction of typical fl uorescent lamps is described. The work compares also current technologies which can be utilized for an efficient recovery of REEs from phosphors powders coming from spent fluorescent lamps. The work is especially focused on the hydrometallurgical and pyrometallurgical processes. It was concluded that hydrometallurgical processes are especially useful for the recovery of REEs from spent fluorescent lamps. Moreover, the methods used for recycling of REEs are identical or very similar to those utilized for the raw ores processing.
Results of pervaporation (PV) of sucrose and calcium chloride spent solutions were presented. Additionally, osmotic membrane distillation (OMD) of sucrose solutions was investigated. It was found that the regeneration of spent sucrose solution for the reuse is possible by using PV or OMD processes. However, OMD process produces another spent stream i.e. CaCl2. Pervaporation membranes showed fluxes in the range of 0.5 - 0.9 kg m-2 h-1 in contact with 40° Brix sucrose solution, whereas OMD water permeate fluxes were in the range of 4 - 5 kg m-2 h-1 for the same feed concentration.Two different hybrid processes were suggested: i) pretreatment followed by OMD reconcentration of spent sucrose solution and independently PV for CaCl2 regeneration; ii) membrane pretreatment (MP) followed by PV of sucrose solution. Based on the experimental results, the membrane areas for both systems were calculated and compared. MP-PV system seems to be a better solution for the spent mixtures management.
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