29% P<sub>2</sub>O<sub>5</sub> Phosphoric Acid Desulphation: Improving the Performance of the Unit of Concentration

Abstract

Clogging in the heat exchangers of the phosphoric acid concentration unit is a phenomenon which hinders the proper functioning of the installation. It results in the accumulation of undesirable solid deposits on the pipes and consequently a decrease of its performance. This deposit is mainly anhydrous or hemihydrate gypsum in addition to Na 2 SiF 6. Phosphoric acid desulphation before its concentration step allows reducing this undesirable effect. Barium carbonate is used for the retention of sulphate ions using a simple experimental protocol which can easily be inserted into the phosphoric acid manufacturing. Four factors: quality of the phosphoric acid to be concentrated, amount of barium carbonate, temperature and time, were studied using design of experiment (DOE) methodology with two-level full factorial design strategy in order to assess their effects on desulphation. Only the first two factors have significant effects. Therefore, for effective sulphate removal, the validated statistical model (R 2 = 99.96%) allows to predict the amount of barium carbonate to be used, depending on quality of the phosphoric acid to be concentrated and using the available temperature and time in the industrial process.

Removal of Organic Matter from Tunisian Industrial Phosphoric Acid by Adsorption onto Purified Natural Illite/Kaolinite Clay: Kinetics, Isothermal and Thermodynamic Studies

“…The elemental composition is determined using an atomic absorption spectrophotometer coupled with inductively coupled mass spectrometry [ 32 ] at the Tunisian Chemical Group laboratories in Gabes.…”

Wet Process Phosphoric Acid Purification Using Functionalized Organic Nanofiltration Membrane

“…In order to maintain the high efficiency and to extend the lifetime of the modified membrane it is necessary to pretreat the industrial PA to avoid the clogging of the porous membrane. Numerous methods have been used to desulfate industrial PA, e.g., the utilization of BaCO3 [22], CaHPO4•2H2O [4] or natural material consisting mainly of calcite…”

“…In order to maintain the high efficiency and to extend the lifetime of the modified membrane it is necessary to pretreat the industrial PA to avoid the clogging of the porous membrane. Numerous methods have been used to desulfate industrial PA, e.g., the utilization of BaCO 3 [22], CaHPO 4 •2H 2 O [4] or natural material consisting mainly of calcite (Ca 0.97 Mg 0.03 CO 3 ), quartz (SiO 2 ) and a low clay fraction (illite) [23]. The dearsenification is carried out through arsenic precipitation as arsenic sulfide, arsenic removal by electrodeposition [24] or by a vertical zone melting technique [25].…”