ABSTRACT
Making particles by gas phase chemical reactions is a fascinating process. It makes some of the most widely used fine particulate commodities and sophisticated nanomaterials. At the same time, this process is responsible for the generation of air pollutants with profound effects on human health and environment. Particles can be made by chemical reactions either in the gas-phase, the so-called gas-to-powder conversion route, or within suspended aerosol droplets in gases, the so-called droplet-to-powder conversion route. Sometimes precursors are fed as droplets that fully evaporate so particles are formed solely by gas-to-powder conversion. Typically precursor droplets flow through a high temperature chamber to drive the chemical reactions within the droplet components and/or the carrier gas. As particle growth takes place in high temperatures, the residence time there, the so-called high temperature particle residence time, is of importance. Besides average particle size, particle growth by rapid coagulation facilitates rapid attainment of their self-preserving size distribution.
