Abstract
Fine grinding in a range of below 30 µm is an issue which has become more and more important over the past years. The reason behind is explained by the fact that deposits of high quality will become more rarely in future and those which complex intergrowth ratios will increase. Beside valuable ore content it is the degree of liberation which rates the value of a deposit.
Based on this market trend the Austrian company Cemtec together with Montanuniversitaet Leoben started the development of a new attrition mill which is now available to the market.
Attrition mills make use of the interaction between a vertical or horizontal rotating stirrer, grinding media and the material to be ground. The main operating grinding stresses are friction forces and therefore the shear rate between rotating and static elements within the mill should be maximized. The chosen approach was to perform extensive experimental test work in the lab of Cemtec on the one hand and in addition use the method of discrete elements simulation (DEM) to explore different kinds of stirrers, grinding media sizes and other geometrical features leading to increased power consumption at low stirrer speeds on the other hand. As friction is the dominant force wear rate of exposed materials are a significant criteria in operating the mills.
Based on mentioned extensive simulation work the chosen geometry is based on a vertical stirrer concept containing rotating and static pins. The simulations were verified and confirmed by test work on a prototype mill with 90 kW installed power. In the meantime the developing partners gained information on the operational behavior of the new mill based on various industrial minerals and ores. As the first mills are already in operation interesting facts on the optimized transfer size between up-stream ball mills and stirred media mills can be shared. Along going with the transfer size it is of interest to prove the actual gains in terms of specific grinding energy using a stirred media mill compared with traditional comminution technology like ball milling or vertical roller milling.
The presented paper will give an outline from development work, simulation, pilot test work up to so far collected operational experience with Cemtec’s attrition mills.
Based on this market trend the Austrian company Cemtec together with Montanuniversitaet Leoben started the development of a new attrition mill which is now available to the market.
Attrition mills make use of the interaction between a vertical or horizontal rotating stirrer, grinding media and the material to be ground. The main operating grinding stresses are friction forces and therefore the shear rate between rotating and static elements within the mill should be maximized. The chosen approach was to perform extensive experimental test work in the lab of Cemtec on the one hand and in addition use the method of discrete elements simulation (DEM) to explore different kinds of stirrers, grinding media sizes and other geometrical features leading to increased power consumption at low stirrer speeds on the other hand. As friction is the dominant force wear rate of exposed materials are a significant criteria in operating the mills.
Based on mentioned extensive simulation work the chosen geometry is based on a vertical stirrer concept containing rotating and static pins. The simulations were verified and confirmed by test work on a prototype mill with 90 kW installed power. In the meantime the developing partners gained information on the operational behavior of the new mill based on various industrial minerals and ores. As the first mills are already in operation interesting facts on the optimized transfer size between up-stream ball mills and stirred media mills can be shared. Along going with the transfer size it is of interest to prove the actual gains in terms of specific grinding energy using a stirred media mill compared with traditional comminution technology like ball milling or vertical roller milling.
The presented paper will give an outline from development work, simulation, pilot test work up to so far collected operational experience with Cemtec’s attrition mills.
| Original language | English |
|---|---|
| Title of host publication | Proceedings of the 14th European Symposium on Comminution and Classification |
| Place of Publication | Gothenburg |
| Pages | 218-221 |
| Number of pages | 4 |
| Volume | 14 |
| Publication status | Published - 2015 |
| Event | 14th European Symposium on Comminution and Classification - Chalmers University of Technology, Gothenburg, Sweden Duration: 7 Sept 2015 → 11 Sept 2015 |
Conference
| Conference | 14th European Symposium on Comminution and Classification |
|---|---|
| Country/Territory | Sweden |
| City | Gothenburg |
| Period | 7/09/15 → 11/09/15 |