A particle forming method includes feeding a first set of precursors to a first
energy application zone. Energy is applied to the first set of precursors in the
first energy application zone effective to react and form solid particles from
the first set of precursors. The application of any effective energy to the solid
particles is ceased, and the solid particles and a second set of precursors are
fed to a second energy application zone. Energy is applied to the second set of
precursors in the second energy application zone effective to react and form solid
material about the solid particles from the second set of precursors. At least
one precursor is fed to at least one of the first and second energy application
zones as a liquid. Other aspects are contemplated.