1490 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
files in one MS Excel spreadsheet, allowing the fast access to
the results and easy distribution of the results.
RESULTS
Figure 1 shows the particle size distribution (PSD) of the
chromite concentrate. It is possible to noted that the d75 was
190 µm, indicating that the material needs further grinding
to prepare it to flotation. Figure 2 presents the PSD after
the milling tests results. In previous works the specific mass
for the chromite concentrate was measured as 3.26 g/cm3,
with an apparent density of 1.81. The Bond Work Index
(Wi) found was 14.67 kWh/t (Oliveira et al. 2023). This
result could help explain the difficult in the chromite con-
centrate milling. A d75 below 100 µm could not be achieve
in a single stage milling, even with the smallest mass (5 kg)
and the highest milling duration (30 min). This result can
lead to a high circulating load in the close circuit. However,
a wet milling could increase the mill performance. In this
work the dry milling was chosen to avoid drying the mate-
rial and agglomeration of the fine particles due the heat.
Another observation that can be draw is that the milling
regime adopted proved to be inadequate, and more tests
Figure 1. Particle size distribution of the chromite concentrate
Figure 2. PSD after 15 minutes (a) and 30 minutes (b) milling
files in one MS Excel spreadsheet, allowing the fast access to
the results and easy distribution of the results.
RESULTS
Figure 1 shows the particle size distribution (PSD) of the
chromite concentrate. It is possible to noted that the d75 was
190 µm, indicating that the material needs further grinding
to prepare it to flotation. Figure 2 presents the PSD after
the milling tests results. In previous works the specific mass
for the chromite concentrate was measured as 3.26 g/cm3,
with an apparent density of 1.81. The Bond Work Index
(Wi) found was 14.67 kWh/t (Oliveira et al. 2023). This
result could help explain the difficult in the chromite con-
centrate milling. A d75 below 100 µm could not be achieve
in a single stage milling, even with the smallest mass (5 kg)
and the highest milling duration (30 min). This result can
lead to a high circulating load in the close circuit. However,
a wet milling could increase the mill performance. In this
work the dry milling was chosen to avoid drying the mate-
rial and agglomeration of the fine particles due the heat.
Another observation that can be draw is that the milling
regime adopted proved to be inadequate, and more tests
Figure 1. Particle size distribution of the chromite concentrate
Figure 2. PSD after 15 minutes (a) and 30 minutes (b) milling