Phosphogypsum (PG) derived from the dissolution of phosphate ore in H2SO4 has been characterized by using chemical and thermogravimetric analyses, X-ray diffraction and infrared spectrum to give an idea about the future utilization of this waste material. The PG under the investigation was free from the radioactive elements and Cd and contained about 141×10-6 rare earth elements in total, which favors the utilization of this material. PG was formed mainly of gypsum, little anhydrite and quartz and rare kaolinite. It exhibited two large endothermic peaks corresponding to the dehydration of the sample and a small one which may be attributed to the liberation of the residual water that may be found in the soluble anhydrite. Also, an exothermic peak was observed which may be related to the transformation of soluble (γ-anhydrite) to insoluble β-anhydrite. PG exhibited the same absorption bands as that observed for chemical CaSO4.2H2O and natural gypsum samples besides the appearance of a weak band at 840 cm-1 which characterizes the vibration of H2PO4- group.
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