Micronization
Under micronization refers to the significant reduction in average particle size. The micronized powders produced in this way are used in a wide variety of industries. In the field of technical powders as well as for flours and fruit powders, the usual grain sizes between 100 µm and 1000 µm are reduced to a range of 2 µm to 200 µm.
In individual applications, a narrow grain size distribution is required and can be achieved through micronization. In order to avoid a perception on the skin, grain sizes below 70 µm are aimed for and grain sizes below 40 µm in order to avoid a mouthfeel .
Micronization should not be confused with micronization of grain (sudden heating in an infrared oven ).
advantages
One advantage of such reduced particles is u. a. the enlarged surface, which is an important parameter for many interrelationships with the environment (e.g. diffusion processes , dispersing properties ).
Methods
A classic method for producing such fine particles is grinding ( jet mill , cold grinding ), another simple process is the melt dispersion process , furthermore the desired reduction in size is achieved through atomization ( spray cooling , PGSS process ) → spray drying , as well as through bead polymerization .
In the atomization or melt dispersion process, spherical, regular particles with a small surface are predominantly obtained, while in the grinding processes broken, irregular particles with a large surface are obtained. Pearl-shaped particles are obtained in bead polymerization.
With the PGSS process, however, different particle shapes can be produced. Spherical particles can be produced which have a compact shape and a small relative surface area. However, thread-like particles with a very large relative surface can also be produced. Intermediate shapes such as hollow spheres, porous particles or microsponges can also be produced.
Web links
- Materials management: Micronization at hu-berlin.de, accessed on March 31, 2017.
- Toni Gradl: From micronization to the quantum dot (PDF; 423 kB), at herbs-hi-tech.com, accessed on March 31, 2017.
- Milling and Micronization of Pharmaceutical Powders , on coperion.com, accessed March 31, 2017.
Individual evidence
- ↑ Micronize on merriam-webster.com, accessed March 31, 2017.
- ↑ Micronizing and fine grinding down to 2 µm ( Memento of the original from April 1, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. at acu-pharma.com, accessed March 31, 2017.
- ↑ Advantages of the grain reduction ( memento of the original from March 23, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. at lohmann-chemischem.de, accessed on March 31, 2017.
- ↑ Nanosuspensions ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (MS Powerpoint file)
- ↑ Entry on micronized waxes. In: Römpp Online . Georg Thieme Verlag, accessed on March 30, 2017.
- ↑ Sebastian Pörschke: Production of powdered organic waxes and possible applications. Dissertation, Ruhr-Universität Bochum, 2014, urn : nbn: de: hbz: 294-40781 , (PDF; 4.82 MB), pp. 8-12.
