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[May 2005]
Retsch Mill for Production of Nanoparticles
The production of nanoparticles is becoming more and more important in many areas, such as the development of new materials, given that they help to systematically change material properties due to their high reactivity and tendency to bond quickly and easily with surrounding materials.
When producing ultra-fine grinding material with a ball mill, certain stress mechanisms are necessary to ensure that the minute particles can be crushed at all. That is why ultra-fine grinding (colloidal grinding) through mechanical stress is mostly done in liquid media; moreover, it requires a high energy input and pressure and shearing forces which act upon the sample material.
The Planetary Ball Mill PM 100 from Retsch GmbH & Co KG (Haan, Germany) is said to meet these requirements. Thanks to the opposite rotation of sun wheel and grinding jar, the large effective sun wheel diameter and the high rotational speed of the sun wheel, the PM 100 possesses the required energy input for the production of nanoparticles.
Retsch says that ultimately the best possible combination of machine parameters and jar fillings determines the success of a colloidal grinding process. Above all, it is the selection of the grinding jar and the ball filling that has a substantial influence on the grinding results. Grinding jars and beads of zirconium oxide which have a high abrasive wear resistance are especially suitable for ultra-fine grinding. Tests with quartz have shown that with a speed of 500 rpm, a mean fineness of 0.99 microns is achieved after 30 min - after 90 min fineness is down to 0.74 microns.
The reported excellent mass compensation and the free-force compensation sockets of the PM 100 guarantee a smooth running and safe operation of the mill, even when heavy jar masses have to be moved. The operating safety, even for long-term grinding processes is an important feature of the PM 100. The mills are available with one, two or four grinding stations.
www.retsch.de
ENDS