Precipitation of Nanosized and Nanostructured Powders: Process Intensification and Scale-Out Using a Segmented Flow Tubular Reactor (SFTR)

The successful scale-out and process intensification using a segmented flow tubular reactor (SFTR) for ultrafine CaCO3, BaTiO3, and nanosized ZnO from optimized minibatch (20 mL) conditions is presented. The capacity of the SFTR in process intensification was demonstrated by producing ∼ 5 kg batches of BaTiO3 powders with excellent batch-to-batch reproducibility. The SFTR scale-out or numbering-up capacity was demonstrated for a nanostructured CaCO3 in 500 g batches by scaling-out from one to six segmented flow tubular reactors run in parallel (scale-out/-up ratio of 5000 compared to lab batch experiments). The SFTR was then used to demonstrate its potential for nanosized ZnO powders producing 50 g lots of these nanopowders in a continuous process, a scale-out/-up ratio of 250 compared to lab batch experiments without any loss of powder quality. The SFTR allows a precise control of precipitation conditions, leading to an excellent reproducibility in powder characteristics, and shows great promise as a simple production process of powders and advanced nanomaterials with highly controlled properties.