Intensification of precipitation process by means of ultrasound-assisted methods and the selection of reactor type

The presented study is focused on the possibilities of precipitation process intensification by means of processing conditions and the selection of a crystallizer construction. The main goal was to consciously intensify the precipitation and to obtain crystals with the defined characteristics. The research took into account the CaF₂ precipitation. The process was carried out in a tank reactor placed in an ultrasonic bath to increase the turbulence intensity (P_US = 150 W, f = 40 kHz). The results were compared with the previous tests, provided in silent conditions in a stirred tank reactor, Koflo, and Kenics static mixers. For the comparison of measurement data obtained under different operating conditions, a new method was proposed. The method correlates with the results very well. It has been also shown that the use of ultrasounds does not contribute to the increase of the precipitation efficiency but allows to obtain a product with a decreased particle size together with a significant reduction of agglomerates number. Moreover, the advantages and disadvantages of the studied equipment and methods have been explained. The general guidance for the selection of the proper working equipment and operating conditions to consciously stimulate the process has been presented as well.