School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Molecules. 2023 Jun 1;28(11):4490. doi: 10.3390/molecules28114490.
For effective removal and utilization of fluorine resources from industrial wastewater, stepwise removal and recovery of fluorine were accomplished by seeding crystallization and flotation. The effects of seedings on the growth and morphology of CaF crystals were investigated by comparing the processes of chemical precipitation and seeding crystallization. The morphologies of the precipitates were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) measurements. The seed crystal, fluorite, helps improve the growth of perfect CaF crystals. The solution and interfacial behaviors of the ions were calculated by molecular simulations. The existing perfect surface of fluorite was proven to provide the active sites for ion adhesion and formed a more ordered attachment layer than the precipitation procedure. The precipitates were then floated to recover calcium fluoride. By stepwise seeding crystallization and flotation, the products with a CaF purity of 64.42% can be used to replace parts of metallurgical-grade fluorite. Both removal of fluorine from wastewater and the reutilization of the fluorine resource were realized.
为了有效去除和利用工业废水中的氟资源，采用种晶结晶和浮选分步去除和回收氟。通过比较化学沉淀和种晶结晶过程，研究了种晶对 CaF 晶体生长和形貌的影响。采用 X 射线衍射（XRD）和扫描电子显微镜（SEM）测量分析了沉淀物的形貌。晶种萤石有助于提高完美 CaF 晶体的生长。通过分子模拟计算了离子的溶液和界面行为。证明萤石的现有完美表面为离子附着提供了活性位点，并形成了比沉淀过程更有序的附着层。然后通过浮选回收氟化钙。通过分步种晶结晶和浮选，可得到 CaF 纯度为 64.42%的产品，可替代部分冶金级萤石。实现了废水除氟和氟资源再利用。
