磷石膏氟化物的浸取动力学特性

Study on Leaching Kinetic Characteristic of Fluoride in Phosphogypsum

应用旋转圆盘法研究了三峡库区堆放的磷石膏中氟化物的浸取动力学特性。在 2 88～30 8K的温度区间 ,pH =5 .0～ 5 .5的酸度区间和 2 5 8～ 90 0r/min的圆盘转速区间下 ,使用氟离子选择性电极连续在线检测水相氟离子的瞬时浓度 ,得到了磷石膏中浸取氟化物的微分速率常数 ,计算了浸取过程的表观活化能为 19.6kJ/mol。根据微分速率常数特点判断 ,从磷石膏浸取氟化物的微观控制过程为外部扩散步骤 ,提高过程温度及旋转圆盘转速据可提高磷石膏中氟化物的浸取速率。

The leaching of fluoride in phosphogypsum piled up in three gorge reservoir area was conducted by rotating disk method. In the following experimental condition: temperature range: 288～308 k, PH value range: 5.0～5.5 and the rotate speed of disk range: 258～900 r/min, the differential rate constant of leaching fluoride in phosphogypsum was concluded by on-line detection of instantaneous concentration of fluorine ion in aqueous phase using fluorine ion-selective electrode. In addition, it was calculated that the apparent activation energy in the process of leaching is 19.6 KJ/mol. From the differential rate constant, it was found that the micromechanism for leaching fluoride from phosphogypsum is exterior diffusion control process and that the improvement of the experimental temperature and rotate speed of disk can get the improvement of the speed of leaching fluoride from phosphogypsum.