Characterization and purification of waste phosphogypsum to make it suitable for use in the plaster and the cement industry

摘要

The phosphoric acid production in Morocco generates a large amount of phosphogypsum (PG) which is a significant source of environmental contamination. In this work, PG has been characterized by different analysis techniques that allow to study the effect of the impurities on its physical and chemical properties. Thus, a method to purify the PG from phosphates and fluorides was proposed in order to improve its quality and to make it usable in plaster and cement. The purification process consists to sieve PG under 200 mu m and to treat it by sulfuric acid to dissolve the insoluble impurities. The obtained results show that the treatment of PG by sulfuric acid 20 and 50% at 60 degrees C for 2 h is sufficient to make it suitable for used in the plaster and the cement respectively.