Calcium carbonate precipitation using new segmented flow tubular reactor

A new segmented flow tubular reactor for the continuous production of powde rs was used to synthesize calcium carbonate by precipitation. This new reac tor uses a nonmiscible phase (air in most cases) to create individual micro volumes of the reacting mixture or suspension ensuring that a plug-flow reg ime is maintained. In a microvolume, poor micromixing can be avoided and th e homogeneity in reaction conditions is increased better than in larger vol umes, leading to a better control of powder characteristics. Calcium carbon ate with controlled characteristics could be precipitated continuously usin g this new segmented flow tubular reactor. Pure calcite could be obtained i n the tubular reactor by segmenting a Ca2+ solution with a reactive CO2/NH3 gas mixture. This synthesis process is very promising for industrial produ ction since the scale-up should easily be achieved by multiplying the numbe r of tubes working in parallel.