New synthesis of hydroxyapatite from local phosphogypsum

This present study relates a new process for direct synthesis of hydroxyapatite crystalline (hap) from anhydrite extracted from moroccan phosphogypsum (pg) waste. hap was performed by reacting hydrated anhydrite with phosphoric acid in the presence of naoh at low temperature in reactor elaborated in our laboratory. the proposed method leads to the obtaining of hap with a ca/p ratio equal to 1,667 which is close to 1,67 found in human bone and indicating stoichiometric hap with a high degree of crystallinity,purity and a high yield. the advantage of this new process is to produce a crystalline hap with particle size ranging from 0,1 to 0,4 μm and high free from al,p,f,si,fe,mg the most pollutant element that hinder the utilization of the pg waste. the provide hap can be used for the treatment of liquid and gaseous effluents. the structural characteristics of hap were determined by the x-ray diffraction (xrd),fourier transform infrared spectroscopy (ft-ir) and scanning electron microscopy-edx. © 2017,university of mohammed premier oujda morocco.