Industrial & Engineering Chemistry Research · 1997 · 27 citations · 4 references
Natural SciencesMaterials EngineeringMaterials ScienceCrystal StructureInorganic ChemistryMineral ProcessingCrystal Habit AnalysisCrystallization ProcessesGypsum MaterialsMineral GenesisPhosphate MineralogyPhosphate MineralsCrystal HabitCrystal Habit ObservationCrystal Habit PolymorphismCrystallization KineticsGypsum Crystal GrowthImpurity Effects On CrystallizationImpurity Effects On HabitPhosphoric Acid Production
There is a poor understanding of the effect of impurities in phosphate rock on the crystal habit of gypsum during wet-process phosphoric acid production. The present work studies the effects of Al 3+, SiF 6 2-, and F - on the habit of gypsum in an MSMPR crystallizer. It is found that the gypsum crystal shape changes little in the presence of Al 3+ alone. In the presence of both Al 3+ and F -, the shape of the gypsum crystal changes greatly and forms sphere-shaped aggregates instead of the elongated needles formed in the presence of Al 3+ . In the presence of F -, Al 3+, and SiF 6 2- ions, the gypsum crystal shape is similar to that in the presence of both F - and Al 3+ ions. In addition, the effects of Al 3+, SiF 6 2-, and F - on the crystallization kinetics of gypsum are also investigated.
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