Three-zone approach for precipitation of barium sulphate

The three-zone approach, introduced by Gosele and Kind [1] [Chem. Ing. Tech. 63 (1991) 59], has been used to investigate BaSO4 precipitation. Experimental relations for the growth and nucleation of BaSO4 are found that show good agreement with those of Angerhofer [2][Thesis, TU Munchen, 1994] and Van der Leeden [3][Thesis, TU Delft, 1991]. The parameters studied in the three-zone approach are the feed concentration, circulation time and volume of the zones. Preliminary results show that the model used correctly predicts the influence of the above-mentioned parameters on the mean particle size and the conversion. Experiments conducted at various mixing conditions in the 3 zones show that the influence of the parameters becomes stronger when the mixing in the 3 zones becomes less intensive. This influence cannot be explained by the present model, which assumes that the zones are ideally mixed.