| Summary: | 碩士 === 大葉大學 === 環境工程學系碩士班 === 101 === The purpose of this study is to develop a recovery method for the recycling of rare earth metals europium and yttrium from spent fluorescent phosphor. The main processes involved in this study include the collection of spent fluorescent phosphors, content analysis, leaching, pH adjustment, crystallization, precipitation, replacement and other methods for europium, yttrium and aluminum,. The content of Eu, Y and Al were 1,831 mg/kg, 27,502 mg/kg and 6,178 mg/kg respectively. In these samples the water content, ash content, combustible material and density was 0.01%, 99.99%, 0.01% and 2.58 g/cm3 respectively. The optimum leaching conditions for the leaching recovery of 100% Eu, 100% Y and 89.4% Al was determined to be 4N hydrochloric acid at 700C for one hour with an initial solid-liquid ratio of 3g/50ml of the impregnated solution. A pH adjustment to 1.2 using sodium hydroxide was determined to be the most efficient for impregnation. Precipitation was used to remove europium and yttrium from solution as a precipitate. This precipitation concentrated europium and yttrium 19 and 17 fold respectively. After the removal of these precipitates aluminum can be removed from the solution as aluminum hydroxide by pH adjustment to 7.
|
|---|
