Measuring size distribution of organic and inorganic crystals of different shapes using different technologies

Kumar Patchigolla

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The ultrasonic attenuation (UA) technique was developed to measure not only particle size distribution (PSD) but also concentration for on-line and off-line analysis of high concentration dispersions. Another significant characteristic along with particle size is particle shape. Particle shape influences the apparent particle size as measured by various instruments. Currently, acquiring particle size along with shape measurement is not readily achieved. Image analysis measures shape with size distribution but only for very small samples, not generally practical for the process industries. Shape factors have been calculated from microscopic images using conventional image analysis (IA) techniques. Particle sizing data measured by UA is more representative than by IA because much larger samples are used for analysis. In this paper, size distributions obtained by ultrasonic attenuation (UA), laser diffraction (LD), focused beam reflectance measurement (FBRM) and image analysis (IA) are compared and the influence of crystal shape on size measurements is investigated. Data obtained from UA has been combined with information on shape factor from imaging to obtain equivalent particle size distributions. Data obtained from LD have been converted with a shape factor (sphericity) from imaging to obtain true Crystal size distribution (CSD). In a previous study [1], the influence of shape on size measurement has been investigated using different sizing techniques for non-fragile materials. These particles showed significant variation in measured PSD with their different shapes. In this paper, the same phenomenon was observed with evolving polymorphs of L-glutamate crystals (a and (3 form) and non-polymorphic oxalic acid and copper sulphate.

Original languageEnglish
Title of host publicationAIChE Annual Meeting, Conference Proceedings
Subtitle of host publication2006 AIChE Spring National Meeting - 5th World Congress on Particle Technology; Orlando, FL; United States; 23 April 2006 through 27 April 2006
Publication statusPublished - 2006
Event2006 AIChE Spring National Meeting - 5th World Congress on Particle Technology - Orlando, FL, United States
Duration: 23 Apr 200627 Apr 2006

Conference

Conference2006 AIChE Spring National Meeting - 5th World Congress on Particle Technology
CountryUnited States
CityOrlando, FL
Period23/04/0627/04/06

Keywords

  • Crystal size and shape
  • Image analysis
  • Laser diffraction
  • Ultrasonic attenuation and focused beam reflectance measurement

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