Particle size analysis
The particle size analysis is a branch of the mechanical process technology and closely coupled to the materials science . It deals with the characterization of disperse systems with regard to particle size. This material property is usually statistically distributed and, in some systems, time-dependent. The primary goal of particle size analysis is usually to determine the prevailing particle size distribution , whereby the term particle can be understood as a solid particle (grain), liquid particle (droplet) or a gas bubble. Other terms for particle size analysis are: dispersity , grain size , droplet size , bubble size and particle size analysis as well as granulometry , the latter comprising a much more comprehensive characterization of disperse systems beyond the particle size (see particle measurement technology ).
The particle size analysis has a high importance in the industrial sector, as particle properties have a decisive effect on the properties of a product. For example, the particle size plays an important role when assessing the flow behavior of bulk material or the stability of heaps . In contrast, particle size analysis does not include the field of elementary particle physics.
introduction
In the field of mechanical process engineering, a material conversion means above all a change in the state of dispersity , i.e. the fineness of a disperse system . Comminution and agglomeration processes change the physical properties of the products produced through their particle size distribution . Among other things, the breaking strength, the permeability and many other properties are influenced.
target
According to Rumpf, the relationships outlined above lead to the following description of the scope of the particle size analysis:
The product properties depend on the dispersity properties, i.e. that is, a product property is a function of the dispersity property.
This relationship, known as the property function, shows that, in addition to measuring the product properties such as the permeability, their dependence on the dispersity properties must also be examined. Particle size analysis is thus a sub-area of particle measurement technology that focuses specifically on the measurement of dispersity properties.
application areas
General areas of application
The particle size analysis is used u. a. in process characterization (e.g. shredding , agglomeration ), in product quality assurance (e.g. filters , pigments ) and in monitoring the environment (e.g. fine dust ), technical systems (e.g. E.g .: clean rooms ) and system parts (e.g .: filters, centrifugal separators ). In research and development , particle size analysis is used to determine product property functions and for process optimization .
Product property function
The quality of chocolate , which is a complex-disperse system of heterogeneously distributed components, depends u. a. on the fineness of the cocoa powder and the sugar crystals in the cocoa butter. If the dispersed constituents in the chocolate exceed a corresponding particle size, they are unpleasant to feel on the tongue .
The duration of the release in the human body of medicinal substances or the carrier substances is fundamentally determined by the fineness of these.
Procedure
Measurement methods for particle size analysis are primarily based on the different physical properties of the particle systems to be analyzed. Depending on the particle size, the prevailing continuous phase and the particle concentration, different measurement methods are used.
| Size range | Concentration range | Procedure | |
|---|---|---|---|
| Aerosol | 0.3 µm to 40 µm | Photo sedimentation | |
| Aerosol | 0.005 µm to 1 µm | ≤ 50,000 cm −3 duct −1 | electric mobility analysis |
| Aerosol | 0.005 µm to 3 µm and larger | ≤ 50,000 cm −3 | Condensation nucleus count |
| Aerosol | Impact separation | ||
| Aerosol | 0.3 µm to 3 mm | Laser diffraction | |
| emulsion | Sound attenuation spectroscopy | ||
| Bulk material | Sieve analysis | ||
| Bulk material | ≥ 1 µm | Light microscopy | |
| suspension | 0.3 µm to 3 mm | Laser diffraction | |
| suspension | dynamic light scattering | ||
| suspension | ≥ 1 µm | Light microscopy | |
| suspension | Photo sedimentation | ||
| suspension | Ultrasonic attenuation spectroscopy |
See also
literature
- Matthias Stieß: Mechanical Process Engineering - Particle Technology 1st 3rd edition, Springer-Verlag, Berlin / Heidelberg 2009, ISBN 978-3-540-32551-2 .
- Kurt Dialer, Kurt Leschonski, Ulfert Onken: Basics of process engineering and reaction technology . Hanser reference book, Munich 1986, ISBN 3-446-14560-5
- Kurt Leschonski: Fundamentals and modern methods of particle measurement technology . Institute for Mechanical Process Engineering and Environmental Process Engineering, Clausthal University of Technology, 1988
- Hans Rumpf, Kurt Leschonski: Lectures of the 1st European Symposium "Particle Measurement" in Nuremberg 17. – 19. September 1975. (= DECHEMA Monographien. Volume 79) Verlag Chemie, 1976.
Individual evidence
- ↑ Matthias Stiess: Mechanical process engineering - Particle technology 1. 3. completely revised. Ed., Springer, 2009, ISBN 978-3-540-32551-2 ., P. XII.
- ↑ Hans Rumpf: About the properties of utility dust. In: Dust - keeping the air clean. 27, No. 1, 1967, pp. 3-13.
- ↑ a b Skoog, DA; Holler, FJ; Crouch, SR: Instrumental Analytics. , 6th edition, Springer , Berlin / Heidelberg, 2013, ISBN 978-3-642-38169-0 , pp. 931-934.
- ↑ Frank Babick: Schallspektroskopische characterization of submicron emulsions. Dissertation, Technical University of Dresden, 2005 ( PDF ).
- ↑ Andreas Richter: Ultrasonic damping spectroscopy of coarsely dispersed systems. Dissertation, Technical University of Dresden, 2008 ( PDF ).