本研究以批次式反應器處理電子業含磷廢水，在不同濃度的磷酸下(1,000~20,000 mg/L)，以氯化鈣作為沉澱劑，產生高純度磷灰石(Ca5(PO4)3OH)。當鈣對磷酸的莫耳比為5:3，酸鹼值為8時，可移除94~99%的磷酸。實驗系統的平衡計算是由電腦軟體PHREEQC所模擬，且模擬與實驗結果作比較。我們證明在適當的莫耳比與酸鹼值可以生成磷灰石沉澱，利用X光繞射分析與濕式化學分析，證明固體沉澱物為磷灰石。我們也設計尺寸放大10公升的模型反應器，結果顯示，移除率與結晶性質與瓶杯實驗的結果相符，後續也針對沉澱時間、濁度與產率進行分析，在高濃度磷酸條件下，磷灰石因顆粒小導致不易沉澱，因此在實驗中也加入適量的聚電解質幫助減少沉澱時間。我們也討論兩階段串聯系統，第一階段為生成磷酸氨鎂;第二階段添加鈣鹽生成磷灰石，結果顯示可以順利形成磷灰石沉澱且磷酸達到放流水標準。由於電子業廢水成份單純、濃度高，因此磷酸加入鈣鹽回收成磷灰石，不只可以減少汙泥的排放，在成本亦具有相對優勢。

The current study aims to develop a treatment technology for phosphate-containing wastewater from electronics industries to produce high-purity hydroxyapatite (HAP). Calcium chloride (CaCl2) was used as precipitation reagent. When at molar ratio ([Ca]:[PO4]) of 5:3 and pH 8, total of 94~99 % of phosphate was removed at different initial phosphate concentration (1,000~20,000 mg/L). Theoretical equilibria were modeled with PHREEQC and compared with experimental results. Characterization of solid precipitates using X-ray diffraction (XRD) and wet chemical analysis confirmed the presence of HAP. A pilot scale system consisting of a 10-dm3 reactor was used as well. The results of phosphate removal efficiency and the property of solid were similar with those from bench scale reactor. Settling time, turbidity and yield of HAP were evaluated. It is difficult for HAP to settle via gravity when at high initial phosphate concentration since the particles were small. Therefore, flocculant was added to improve solid-liquid separation. Compared with conventional phosphate treatment in electronic industry, recovery as HAP could decrease the treatment cost of sludge and recycle and reuse phosphorus as resource. Considering that the composition of semiconductor wastewater is simple and with high concentration, the technology has a tremendous potential to become commercialized.

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