SEMIBATCH PRECIPITATION ACCOMPANYING GAS-LIQUID REACTION

To obtain large particles of insoluble product by precipitation accompanying a gas-liquid reaction, a sparged stirred vessel was operated continuously for the gaseous and liquid reactants but batchwise for the product particles. Except at the beginning of run, most particles formed floes. With increasing concentration of product particles, the average size of floes increased for CaC0₃ but remained unchanged or decreased slightly for SrCO₃ and BaC0₃The effect of agitation on the floc size was significant for CaC03 but scarcely observed for SrC0₃ and BaC0₃ The mass per unit volume of sedimented floes of the three species increased with increasing concentration of product particles, and under the same conditions, they decreased in the following order: CaC0₃ SrC0₃ BaC0₃