Solid-Solid Separation of Fluorescent Powders by Liquid-Liquid Extraction Using Aqueous and Organic Phases

抄録

Two-step liquid-liquid extraction methods using aqueous and organic phases for separation of red (Y₂O₃: Eu³⁺), blue (BaMgAl₁₀O₁₇: Eu²⁺) and green (CeMgAl₁₀O₁₇: Tb³⁺) fine fluorescent powders were proposed in this paper. At first, the blue powder was extracted selectively into heptane phase using a chelating agent, 2-thenoyltrifluoroacetone (HTTA, CF₃COCH₂COC₄H₃S) under alkaline pH condition. Then, chloroform was used for extracting the green powder into the chloroform phase. The red powder separating from the green powder remained in aqueous phase with a depressant, potassium sodium tartrate tetrahydrate (PST, KNaC₄H₄O₆·4H₂O). The powders could be well separated in terms of their grade and recovery. The results suggested directions for future research into the recycling of fluorescent powders from fluorescent lights.