(北京科技大学 冶金与生态工程学院，北京 100083)
摘 要: 基于已有热力学数据，对稀土除磷过程及沉淀产物的再生过程分别进行了热力学计算，绘制了25 ℃下 -pH图，为含磷废水中磷的资源化利用和无害化处置提供理论支撑。结果表明：采用稀土处理含磷废水时在pH 2.70~8.66范围内沉淀，可生成稳定的LaPO4(和CePO4)沉淀，实现磷的去除；再生过程pH在14.5~16.0范围内，LaPO4(和CePO4)可转变为La(OH)3(和Ce(OH)3)实现沉淀剂的再生与磷的回收。采用La(OH)3和Ce(OH)3处理30 mg/L的含磷溶液，磷沉淀率分别为99.72%和96.33%；采用4 mol/L的NaOH溶液分解沉淀产物，反应3 h后La(OH)3和Ce(OH)3的再生率分别为30.38%和63.38%。
关键字: 稀土；除磷；热力学；废水处理
（School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:Based on the available thermodynamic data, the thermodynamic calculation of the phosphorus removal process with rare earth and the regeneration process of precipitation products were carried out, respectively. And the -pH diagram at 25 ℃ was drawn to provide theoretical support for the resource utilization and harmless disposal of phosphorus in phosphorus-containing wastewater. The analysis shows that stable LaPO4 (and CePO4) precipitation can be generated within the pH range of 2.70-8.66 to remove phosphorus. During the regeneration process, LaPO4 (and CePO4) can be transformed into La(OH)3 (and Ce(OH)3) in the pH range of 14.5-16.0 to achieve precipitation regeneration and phosphorus recovery. The results show that when La(OH)3 and Ce(OH)3 were used to treat 30mg/L phosphorous solution, the phosphorus precipitation rates are 99.72% and 96.33%, respectively. After 3h reaction, the regeneration rates of La(OH)3 and Ce(OH)3 are 30.38% and 63.38%, respectively.
Key words: rare earth; phosphorus removal; thermodynamics; waste water treatment
