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Particle size analysis principles

21 January 2011 One Comment

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One of the reasons why Malvern Instruments has gained such a reputation for support and expertise throughout both industry and academia is the company’s open provision of such fundamentally solid learning materials. One of these is a paper on the “Basic Principles of Particle Size Analysis”.

As that paper’s author, it has been extremely gratifying to me to learn that it is the most downloaded document on the Malvern website, with over 7500 downloads during the past 3 years, and has no doubt been printed out and shared around many a laboratory. Readers tell me this document is a concise, but comprehensive, and helpful introduction to the field of materials characterization – particle size analysis pared down as it were!

Just a moment, what does Moment Mean actually mean?

It’s important to understand the basics of particle size analysis and “Basic Principles of Particle Size Analysis” sets out to answer such questions as:

  • How do you describe a 3D particle with a single number?
  • How do you calculate the volume equivalent spherical diameter of a cylinder?
  • How does your numerical result relate to actual particle properties?
  • What is the difference between number-surface, number-volume and number-weight mean?
  • What does D[4,3] mean?
  • Why do different techniques give different results?
  • How do different measuring techniques compare?

From a raised hand to the satisfaction of finding out you’re right…

As a naturally curious bunch, scientists and laboratory personnel all share a thirst for knowledge. My hope is that this document continues to provide the basics, both for those entering the field and others simply wishing to refresh their background knowledge.

Many of us relate to the memory of sitting at our desks at school, hand held so high that we reached off the chair, trying to get the teacher’s attention because we were SURE we knew the answer. Oh the joy and satisfaction felt when our understanding was confirmed as correct… It NEVER hurts to check the basics!

The particle size analysis challenge

Test your knowledge with the following:

1.       What does D[3,2] mean?

2.       Which type of sphere is Stoke’s Law valid for?

3.       Within which range is the sedimentation technique applicable for accurate particle size?

4.       In which decade, and for which application, was Electrozone sensing (Coulter Counter) developed?

5.       In laser diffraction, what is the relationship between diffraction angle and particle size?

6.       How many particles might you find in 1g of 10 micron particles. with density 2.5g/cm3?

If you get all five questions correct without checking out the answers in the “Basic Principles of Particle Size Analysis”, do get in touch, We might just wish to hire you!