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© 2015 iPAT Institut für Partikeltechnik

Increase of the energy efficiency by controlling the flow properties and minimizing the agglomeration in dry fine grinding processes

Contact Person: Paul Prziwara
Fine grinding of various mass products, such as feldspar or limestone, is often carried out in dry operated mills. By using dry instead of wet milling processes, an energy intensive drying step of the ground material becomes unnecessary. Regarding fine grinding processes of other mass products, such as cement clinker or slag sand, wet grinding processes are not even possible due to the high reactivity of the particles with water. The main challenge of dry fine grinding arises with the growing adhesion forces between the product particles with increasing product fineness. These forces induce agglomeration of the particles, adhesives on the grinding chamber, mill equipment or grinding media and a significant decline of the flow properties, which in total is reducing the energy efficiency of the grinding process. 
Fig.: Mechanism of action of grinding aid molecules
 Therefore, grinding additives are established in many industrial applications in order to reduce the particle-particle interactions. Unfortunately, the choice and dosage of the grindings aids is nowadays solely based on empirical knowledge.
The focus of this project is to develop an understanding of the mechanisms of action of the grinding aids. For this purpose, the influence of several additives on the surface as well as flow properties of different ground materials will be investigated. Then, the results will be correlated to the grinding performance in different laboratory mills. Additionally, the transport phenomena of the grinding aids to the particle surface will be regarded as well as the effect of mill parameters and dosage strategies..

Fig.: Process scheme of mill-classifier-circuit
 
In addition to that, new technical possibilities for efficient dry fine grinding processes are evaluated. Therefore, dry operated stirred media mills, which a promising and emerging option for those processes due to their high energy densities, are investigated in both (batch-wise) laboratory as well as (continuously operated) pilot scale.
Finally, the knowledge gained from the grinding aid study will be transferred to grinding processes in grinding-classifying-circuits using horizontal stirred ball mills and deflector wheel classifiers. Thereby, further issues like the impact of grinding aids on material transport and classifier efficiency are focused.the grinding aid study will be transferred to grinding processes in grinding-classifying-circuits using horizontal stirred ball mills and deflector wheel classifiers. Thereby, further issues like the impact of grinding aids on material transport and classifier efficiency are focused.
 
 
 
 

Fig.: Pilot plant with dry operated, horizontal stirred media mill


Team Members

Current Projects
Silicon Graphite goes Industry more

Ultra-fine grinding of multi-component systems in stirred media mills more

Increase of the energy efficiency by controlling the flow properties and minimizing the agglomeration in dry fine grinding processes more

Stress events in planetary ball mills and their application on scaling and mill-changing behaviour more

Nanogrinding of organic and inorganic materials more

Nanogrinding of pharmaceutical ingredients in stirred media mills more

Finished Projects

Presentations