ABSTRACT
This chapter discusses a number of particle sizing techniques ranging from direct and indirect imaging of particles to physical methods of separation by size. Direct imaging is an absolute method of particle size and morphology characterization because it is the only technique in which the instrument itself does not provide some interpretation of the data. Optical microscopy uses visible light to examine particles. The wavelength of light determines the fundamental limit of resolution for this method. Single-particle methods of indirect imaging consist of means of measuring the actions of a single particle at a time. The light-blockage technique of particle sizing is the optical equivalent of the electrical resistance method. Light scattering, or photon correlation spectroscopy, can be used for ensemble sizing of small particles. Sieving is a method of particle size analysis that can also provide size-segregated particles for use in processing. Filtration may be used either for particle size determination or for particle segregation for other purposes.
