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Proceedings Paper

A novel method for determination of particle size distribution in-process
Author(s): Tiberiu A Salaoru; Mingzhong Li; Derek Wilkinson
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Paper Abstract

The pharmaceutical and fine chemicals industries are strongly concerned with the manufacture of high value-added speciality products, often in solid form. On-line measurement of solid particle size is vital for reliable control of product properties. The established techniques, such as laser diffraction or spectral extinction, require dilution of the process suspension when measuring from typical manufacturing streams because of their high concentration. Dilution to facilitate measurement can result in changes of both size and form of particles, especially during production processes such as crystallisation. In spectral extinction, the degree of light scattering and absorption by a suspension is measured. However, for concentrated suspensions the interpretation of light extinction measurements is difficult because of multiple scattering and inter-particle interaction effects and at higher concentrations extinction is essentially total so the technique can no longer be applied. At the same time, scattering by a dispersion also causes a change of phase which affects the real component of the suspension's effective refractive index which is a function of particle size and particle and dispersant refractive indices. In this work, a novel prototype instrument has been developed to measure particle size distribution in concentrated suspensions in-process by measuring suspension refractive index at incidence angles near the onset of total internal reflection. Using this technique, the light beam does not pass through the suspension being measured so suspension turbidity does not impair the measurement.

Paper Details

Date Published: 24 August 2009
PDF: 6 pages
Proc. SPIE 7381, International Symposium on Photoelectronic Detection and Imaging 2009: Material and Device Technology for Sensors, 73811A (24 August 2009); doi: 10.1117/12.835099
Show Author Affiliations
Tiberiu A Salaoru, De Montfort Univ. (United Kingdom)
Mingzhong Li, De Montfort Univ. (United Kingdom)
Derek Wilkinson, Heriot-Watt Univ. (United Kingdom)

Published in SPIE Proceedings Vol. 7381:
International Symposium on Photoelectronic Detection and Imaging 2009: Material and Device Technology for Sensors
Xu-yuan Chen; Yue-lin Wang; Zhi-ping Zhou; Qing-kang Wang, Editor(s)

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