Grinding Samples with Volatile Components
The new Planetary Ball Mill PM 100 CM allows for gentle size reduction with less temperature rise.
The new Planetary Ball Mill PM 100 CM offers all the performance and convenience of the classic PM 100. It pulverizes and mixes soft, medium-hard to extremely hard, brittle and fibrous materials and is used wherever the highest degree of fineness down to the submicron range is required. It is suitable for dry and wet grinding.
In contrast to the PM 100 the speed ratio of sun wheel to grinding jar is 1:-1, i.e. the mill operates in centrifugal mode. This results in a different ball movement so that the sample is not so much crushed by impact effects but more gently ground by pressure and friction which allows for a lower temperature rise in the grinding jar and less abrasion. The PM 100 CM offers an excellent alternative for all applications where size reduction must not necessarily be carried out with maximum energy input.
The figure shows the temperature curve measured inside the grinding jar of the PM 100 CM and a conventional planetary ball mill during grinding of sewage sludge with identical parameters. The measurements were carried out with PM GrindControl. It can be clearly seen that the temperature in the PM 100 CM is considerably lower, even after long grinding times.
Therefore, the PM 100 CM is particularly suitable for grinding temperature-sensitive materials or samples which are to be analyzed for volatile components. When processing plants, for example, it is important that the temperature rise in the jar is kept rather low. For the detection of volatile elements or connections (e.g. mercury in sewage sludge), the PM 100 CM provides neutral-to-analysis size reduction.
The lower energy input is also of advantage for samples which are not temperature-sensitive - caking of the material can be avoided in most cases while obtaining identical grind sizes.