Controlled precipitation is a widely used method of obtaining zinc oxide, since it makes it possible
to obtain a product with repeatable properties. The method involves fast and spontaneous reduction of
a solution of zinc salt using a reducing agent, to limit the growth of particles with specified dimensions,
followed by precipitation of a precursor of ZnO from the solution. At the next stage this precursor
undergoes thermal treatment, followed by milling to remove impurities. It is very difficult to break down
the agglomerates that form, so the calcined powders have a high level of agglomeration of particles. The
process of precipitation is controlled by parameters such as pH, temperature and time of precipitation.