Abstract: A carbonating tower for the production of sodium bicarbonate magma has a hollow casing accommodating perforated plates arranged one above another which divide the inner space of the casing into a separation compartment and reaction compartments communicating with one another via overflow pipes. Each reaction compartment has an annular baffle coaxial therewith arranged adjacent to the upper end of the overflow pipe, the baffle being adapted to define a zone for accumulation of solid crystalline phase in the magma. There are also provided means for removing said magma from one reaction compartment into the next compartment. The provision of the accumulation zone and the means for removal of magma contributes to the reduction of supersaturation of the solution with sodium bicarbonate, whereby crystals of uniform shape and size are obtained.