# Ginding Kinetics Adjustment of Copper Ore Ginding in an Innovative Electromagnetic Mill
## 4 Conclusions  
The optimum particle size distribution should contain the smallest possible number of very fine and very coarse particles. Very fine and very coarse particles are considered as non-flotating, since they do not create stable particle-bubble aggregates (\"elephant curve\"). In the case of very fine particles (with the size below 0.005 mm), this is due to the low probability of collision and adhesion, while the coarse particles (ca. 0.3 mm for sulfides and ca. 1.0 mm for coal) are too big and heavy. Grinding and classification should ensure the optimum particle size for flotation while minimizing energy and grinding media consumption. This optimum particle size changes, and is dependent on the size and liberation of the copper-bearing minerals. In this situation, the optimization of the grinding process is a key issue. Flotation is going to be a subject of further studies, since many surface characteristics of the ore have changed after grinding. It requires maintaining certain conditions that guarantee obtaining high-quality flotation concentrates. The appropriate particle size distribution of the feed is achieved thanks to the use of mills in classification and fragmentation nodes. The results of laboratory tests on examined copper ore have shown that an electromagnetic mill enables obtaining the expected particle size of the feed directed to the flotation beneficiation nodes in processing plants. This factor forces communuting the feed to the grain size below 45 um, although in some cases, this limit decreases even to 10 um. Tests of grinding media dedicated to electromagnetic mills showed that the best results were achieved for 10 \(\times\) 1 mm stainless steel grinding media. Obtaining copper ore with a granulation between 0-0.045 mm was possible after almost 25 s of the grinding process. Upon extending the time of material grinding to 30 s in an electromagnetic mill, it was possible to obtain a relative increase in the 0-0.02 mm fraction of c.a. 80%. It can be concluded \begin{table}
\begin{tabular}{c c c} \hline \hline
**Grinding Time (s)** & **Energy Consumption (kWh)** & **Specific Energy (kWh/t)** \\ \hline
5 & 0.025 & 50 \\
10 & 0.05 & 100 \\
15 & 0.075 & 150 \\
20 & 0.1 & 200 \\
25 & 0.125 & 250 \\
30 & 0.15 & 300 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Specific energy consumption in comparison with grinding time. that the use of smaller size grinding media provided faster growth of the studied particle size fractions in grinding products. The relative increase makes it possible to assess the limits of the mill's potential in terms of the further growth of the analyzed particle size fraction. A comparison of the work of a mill loaded with specific grinding media through relative growth makes it easier to evaluate the efficiency of grinding; achieving 100% of the increment of the analyzed particle size fraction indicates the high efficiency of the mill in the grinding of a given particle size. An important element of the analysis is also the time at which the high increment values are achieved. It is also important to observe the state of saturation (no increment), which indicates the limit of the mill's ability to further commune the material in the case of increments with values lower than 100%. On the basis of the research, models based on the distribution of one-parameter exponential distribution were also prepared. The degree of their adjustment to the experimental data in most cases exceeded 90%, which is a solid basis for conducting project processes and further analysis of the phenomenon. [PERSON], [PERSON], [PERSON] conceived and designed the grinding and classification circuits, [PERSON], [PERSON], [PERSON] conceived and performed the batch experiments, [PERSON] and [PERSON] prepared samples and performed laboratory analysis, [PERSON], [PERSON], [PERSON] designed and solved grinding kinetics models, [PERSON] and [PERSON] wrote the paper. The research reported in this paper as well as the open access charge was co-financed by statutory activities AGH No.