3870 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
shown in Figure 13. Unfortunately, the feed material of the
wet milling test was remarkably coarser. It is therefore not
surprising that lower throughputs were achieved. Figure 11
shows the results of the calculated circulation factor.
Because the mill throughput is set via the PLC, the cir-
culation factor has to behave oppositely to the feed mate-
rial throughput. Therefore, at a lower milling pressure the
circulation factor is the highest as well as at a lower mill-
ing table speed. At a milling table speed of 0.66 m/s, the
correlation between the circulation factor and the milling
pressure is nearly linear. The comparison shows, that the
dry process reaches an average circulation factor of 5.7
while the wet process reaches about 8.7. This result already
considers the moisture of the recirculated material, in terms
of only using the solid throughput. A higher circulation
factor could also indicate a poorer screen performance. This
would be reflected in the particle size distributions of the
coarse material by a higher content of fines, but as shown
in Figure 14 there isn’t a remarkable difference compared
to the dry milling tests. Thus, the higher circulation factor
Figure 11. Variation of the circulation factor as a function of milling pressure and milling table speed
Figure 12. Variation of the specific energy consumption as a function of milling pressure and milling table speed
shown in Figure 13. Unfortunately, the feed material of the
wet milling test was remarkably coarser. It is therefore not
surprising that lower throughputs were achieved. Figure 11
shows the results of the calculated circulation factor.
Because the mill throughput is set via the PLC, the cir-
culation factor has to behave oppositely to the feed mate-
rial throughput. Therefore, at a lower milling pressure the
circulation factor is the highest as well as at a lower mill-
ing table speed. At a milling table speed of 0.66 m/s, the
correlation between the circulation factor and the milling
pressure is nearly linear. The comparison shows, that the
dry process reaches an average circulation factor of 5.7
while the wet process reaches about 8.7. This result already
considers the moisture of the recirculated material, in terms
of only using the solid throughput. A higher circulation
factor could also indicate a poorer screen performance. This
would be reflected in the particle size distributions of the
coarse material by a higher content of fines, but as shown
in Figure 14 there isn’t a remarkable difference compared
to the dry milling tests. Thus, the higher circulation factor
Figure 11. Variation of the circulation factor as a function of milling pressure and milling table speed
Figure 12. Variation of the specific energy consumption as a function of milling pressure and milling table speed