A theoretical analysis of the processes proceeding during treatment of agglomerated particles in plasma flows is performed within the context of obtaining hollow microspherical powders from such particles. For the first time, approximate theoretical solutions were used to formulate the criteria to the plasma flow, and also the criteria to the particle material characteristics, whose realization is required for forming hollow microspheres with maximum possible diameter and minimum wall thickness of the particle shell. The study can prove useful for workers engaged in the development of processes for obtaining and application of powder materials.