Prediction and study of the industrial performances of phosphate rock before valorization to phosphoric acid

The reaction between apatite and sulfuric acid, which produces soluble phosphoric acid and insoluble phosphogypsum, is the main reaction taking place in a phosphoric acid plant. Nevertheless, there are side reactions’ involving some desirable and undesirable impurities. The present paper aimed to study and evaluate the performances and behavior of four grades of mineral phosphates coming from four different Moroccan mining sources (Khouribga, Youssoufia, Benguerir, and Bucraa) before their valorization to phosphoric acid via the wet dihydrate process. In the logic of preventing impurities’ impact and acting at source according to the first principle of green chemistry and using ratios established by different authors, the main effects of some impurities such as F − - ions, CO 2 , SiO 2 , SO 3 , Al 2 O 3 , Fe 2 O 3 , MgO, K 2 O, and Na 2 O on phosphoric acid process performances (reactivity, sulfuric acid-specific consumption, phosphoric acid viscosity, foam formation, filterability, fouling, and corrosion) were identified and extensively investigated through leaching tests. Additionally, a practical thermal balance was established and showed that impurities could contribute 32% of the total heat released during the attack of apatite and consume 33% of dedicated sulfuric acid.