RECOVERY AND CHARACTERIZATION OF PHOSPHOR POWDERS FROM WASTE LINEAR TUBE FLUORESCENT LAMPS

Nowadays, recycling of rare earth elements (REEs) from end-of-life fluorescent lamps (FLs) is recommended, in order to secure these elements acquisition at reasonable prices and to limit their scarcity impact worldwide. In this work, a new method of pre-treatment of FLs is suggested, trying to develop an effective technique that allows the recovery of phosphor powders (PPs) covering the inner walls of a FL and containing the sought REEs. This experimental study presents tests performed on linear tube fluorescent lamps at the end of their life, in order to isolate luminescent powders through wet processing. The effects of the pretreatment method used on the physicochemical properties of the extracted PPs were investigated using multiple methods by scanning electron microscopy (SEM), particle size analysis, X-ray diffraction (XRD), X-ray fluorescence (XRF) and atomic absorption analyses. The last technique enabled to identify any contamination in toxic mercury of filtration waters obtained after recovery of the PPs. Indeed, the pretreatment technique used is a very green and economical alternative to the techniques described in detail in the state of the art. This was confirmed by obtaining a raw powder containing low silica explained by the presence of minimum debris of glasses. Thus, it has been shown through elementary analysis, the interest of this lamp type collection and pretreatment at the end of life before their discharges, while avoiding the release of mercury in the environment, and to have a powder ready for the extraction treatments allowing separating the individual REEs.