Particle-size analysis

This article describes the determination of the size of particulate solids, where the meaning of the particle excludes those of subatomic particles, which belong to the field of particle physics.

Particle size analysis, particle size measurement, or simply particle sizing is the collective name of the technical procedures, or laboratory techniques which determines the size range, and/or the average, or mean size of the particles in a powder sample.

Particle size analysis is part of Particle Science, and its determination is carried out generally in particle technology laboratories.

The particle size can have considerable importance in a number of industries, but perhaps chiefly in the chemical industry, when one of the reactants is a powder, or when in a chemical reaction the catalyst is in a pulverised state, either in a fixed bed, or in a fluidised reactor.

"The Particle Technology Forum", an international and interdisciplinary forum, but also a division of the American Institute of Chemical Engineers says: «...particle technology -- that branch of science and engineering dealing with the production, handling, modification, and use of a wide variety of particulate materials, both wet or dry, in sizes ranging from nanometers to centimeters... spans a range of industries to include chemical, petrochemical, agricultural, food, pharmaceuticals, mineral processing, advanced materials, energy, and the environment»

There are a large number of methods for the determination of particle size, and it is important to state at the outset, that these different methods are not expected to give identical resülts: the size of a powder depends on the method used for its measurement, and it is important to chose that method for its determination which is relevant to its use.

A few examples, to be extended, and completed later are given here:
* sieving
* sedimentation
* elutriation
* microscope counting
* using a Coulter counter