摘要
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 Na2SiF6. 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 (R2 = 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.
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 Na2SiF6. 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 (R2 = 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.
