Preparation of Calcium Fluoride using Phosphogypsum by Orthogonal Experiment

Abstract

The resource utilization of phosphogypsum is confronted with great challenge. Of all the different methods for phosphogypsum resource utilization, using phosphocypsum to fabricate calcium fluoride (CaF2) is an effective resource utilization method. In this work, high-quality nano-calcium fluoride was successfully prepared in aqueous solution using calcined phosphogypsum by direct precipitation method. A series of orthogonal experiments were carried out in study. Here, the calcined phosphogypsum powder was mixed with NH4F to react at 40°C for 70 min according to the optimum molar ratio (Ca/F=0.4). Meanwhile, the residue obtained by separating the mixture reacted was dried at 120°C for 90min. After preparation, the nano-calcium fluoride was analyzed by X-ray diffraction and scanning electron microscope, results found that the average particle diameter of calcium fluoride was around 70 nm. This work could increase the industrial chain of phosphogypsum application and apply a method to solve the fluorite resource shortage.