1：Experimental Design and Method Selection:

The study involved mechanical separation of phosphor powder from discarded CFLs, followed by characterization using XRF, XRD, and SEM/EDS. Leaching experiments were conducted with inorganic acids (HCl, HNO3, H2SO4) at controlled conditions, and precipitation of REEs was performed using oxalic acid. A Box-Behnken response-surface design was used for optimization of milling time, acid concentration, and leaching time.

2：Sample Selection and Data Sources:

End-of-life CFLs were procured from a local electric warehouse. The phosphor powder was separated by sieving below 53 μm size.

3：List of Experimental Equipment and Materials:

Equipment included a planetary ball mill (Retsch PM 100), X-ray fluorescence (XRF) spectrometer (Rigaku Supermini 200), X-ray diffractometer (XRD, Rigaku Smart Lab), scanning electron microscope with EDS (Fe-SEM, Zeiss EVO18), magnetic stirrer (C-Mag HS-7, IKA), pH meter (Cole-Parmer P100), and laboratory oven. Materials included tungsten carbide jars and balls, inorganic acids (HCl, HNO3, H2SO4), oxalic acid, and other chemicals for precipitation.

4：Experimental Procedures and Operational Workflow:

CFLs were shredded and components separated. Phosphor powder was milled in a planetary ball mill for specified times, then leached in acid solutions at 40°C with stirring. Leach residues were filtered and dried. REEs were precipitated from leach solutions using oxalic acid at controlled pH, and precipitates were calcined at 900°C to obtain rare earth oxides (REOs).

5：Data Analysis Methods:

Data were analyzed using statistical software (Design Expert-11) for optimization. Dissolution percentages were calculated based on XRF analysis, and phase identification was done via XRD and EDS.