教師資料查詢 | 類別: 期刊論文 | 教師: 李奇旺 Chi-Wang Li (瀏覽個人網頁)

標題:Fluoride recovery from spent fluoride etching solution through crystallization of Na3AlF6 (synthetic cryolite)
學年103
學期1
出版(發表)日期2014/11/24
作品名稱Fluoride recovery from spent fluoride etching solution through crystallization of Na3AlF6 (synthetic cryolite)
作品名稱(其他語言)
著者Chen, Jie-Yuan; Lin, Chih-Wei; Lin, Po-Han; Li, Chi-Wang; Liang, Yang-Min; Liu, Jhy-Chern; Chen,Shiao-Shing
單位水資源及環境工程學系暨研究所
出版者
著錄名稱、卷期、頁數Separation and Purification Technology 137, pp.53-58
摘要Fluoride removal by precipitation of calcium fluoride is the most common practice in Taiwan to treat fluoride-containing wastewater in semiconductor or optoelectronic industries. Due to very fine CaF2 precipitates (∼0.1 μm), coagulants/flocculants are needed to facilitate sedimentation of CaF2. In turn, large amount of sludge is produced by CaF2 precipitation/sedimentation process. In this study, removal of fluoride from spent fluoride etching solution by cryolite crystallization was investigated. Experimental and chemical equilibrium modeling results show that a good control of reaction pH and Al:F molar ratio is the key to form cryolite successfully. Formation of cryolite is exothermic reaction and formation of cryolite is less favor under elevated temperature. The highest residual fluoride concentration is found at reaction temperature of 90 °C while those at 20 and 55 °C are similar. Under Al/F molar ratios of 1:3 and 1:6 and pH of 5.5, the precipitates produced at room temperature are very similar to the commercial cryolite according to XRD, SEM, and EDX analysis. Particle size of cryolite precipitates ranges from 3 μm to 15 μm and is much larger than CaF2 precipitates of 0.1 μm, resulting in rapid sedimentation. Cryolite crystallization process produces much less sludge volume than does by CaF2 precipitation.
關鍵字Cryolite; Crystallization; Etching solution; Recovery
語言英文
ISSN1873-3794;1383-5866
期刊性質國外
收錄於SCI;EI;
產學合作
通訊作者Li, Chi-Wang
審稿制度
國別英國
公開徵稿
出版型式,電子版,紙本
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