Determination of phosphogypsum from Romania by SEM-EDAX

Phosphogypsum is a technogenic product remaining after the extraction of phosphoric acid from raw phosphate, mainly apatite. The phosphate rock mainly composed of apatite, and originating from Morocco, Russia, Syria, Jordan and India, is treated with concentrated sulfuric acid (96%), after fine crushing to supra colloidal size and passing into an aqueous solution of phosphoric acid. The morphology of crystals is influenced by the conditions of phosphoric acid manufacture. Most of the analyzed crystalline phases, especially gypsum, have micronic size, are very water absorbing and are detectable only at the level of crystalline individual through the scanning electron microscopy.