3668 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Pelletization Studies of the Siliceous Sample
Similar pelletization techniques, as described above for the
ferruginous sample, were also employed to understand the
pelletization performance of the siliceous overburden sam-
ple. Optimization of both the green balling and induration
parameters was conducted to get the recommended pellet
properties.
Table 3 presents the recommended values for various
balling tests, such as moisture, drop test, and compressive
strength. It is noteworthy that green pellets manufactured
at varying basicity levels have met the required parameters.
While moisture and green compressive strength were uni-
form throughout all basicity levels, the average drop num-
ber steadily rose with an increase in the basicity.
The induration study analyzed dried pellets with vary-
ing basicity levels, induration temperatures, and times
(Figure 14). CCS increased up to 0.25 basicity at 1200 °C
and 1250 °C and then remained constant. At 1300 °C,
CCS increased with basicity up to 375 kg/pellet at 0.35.
Pellets fired at 1200°C didn’t meet the recommended CCS
value of 150 kg/pellet. Porosity decreased with an increase
in basicity, with desirable levels of 18–25% in pellets with
basicity of 0.20 to 0.25.
The induration studies at 20 min also found that a
basicity of 0.25 and a temperature of 1250°C achieved the
desired CCS and porosity of pellets (Figure 15). Pellets fired
at 1250 °C with basicity of 0.35 demonstrated a significant
improvement in CCS, reaching a maximum of approxi-
mately 400 kg/pellet. However, porosity decreased as the
basicity increased from 0.05 to 0.35 at all temperatures.
From the previous section, it has been determined that
for obtaining the desired pellet characteristics, a tempera-
ture of 1250 °C, a time of 10 min, and a basicity of 0.25
are the most suitable conditions. To gain deeper insights
into the metallurgical properties of the pellets, tests were
conducted at this optimum condition. The detailed find-
ings are presented in Table 4, which shows that the pellets
have the recommended properties required for the subse-
quent direct reduction process. This information is crucial
for ensuring the quality and efficiency of the entire produc-
tion process.
Table 3. Physical properties of the developed green pellets
Properties Recommended
Basicity
0.05 0.10 0.15 0.20 0.25 0.30 0.35
Moisture (%)8–10 20.1 19.5 21.0 22.0 21.4 22.1 21.5
Average Drop Number 6.0 31.0 33.0 33.0 37.0 41.0 49.0 55.0
Green Compressive Strength (kg/pellet) 1 1.5 1.7 1.8 2.0 2.2 2.3 2.3
Figure 14. CCS (A) &Porosity (B) vs Basicity at 1200 °C, 1250 °C and 1300 °C (10 min)
Table 4. Metallurgical properties of the fired pellets under
optimum conditions
Parameters
Present
Study Recommended
CCS, kg/pellet 170–180 150, average
Porosity, %18–21 18–25
Tumbler Index, %97.5–98 92
Abrasion Index, %2–2.4 5
Reduction Degradation
Index, %
2.5–3 25
Reducibility Index, %75–80 60
Pelletization Studies of the Siliceous Sample
Similar pelletization techniques, as described above for the
ferruginous sample, were also employed to understand the
pelletization performance of the siliceous overburden sam-
ple. Optimization of both the green balling and induration
parameters was conducted to get the recommended pellet
properties.
Table 3 presents the recommended values for various
balling tests, such as moisture, drop test, and compressive
strength. It is noteworthy that green pellets manufactured
at varying basicity levels have met the required parameters.
While moisture and green compressive strength were uni-
form throughout all basicity levels, the average drop num-
ber steadily rose with an increase in the basicity.
The induration study analyzed dried pellets with vary-
ing basicity levels, induration temperatures, and times
(Figure 14). CCS increased up to 0.25 basicity at 1200 °C
and 1250 °C and then remained constant. At 1300 °C,
CCS increased with basicity up to 375 kg/pellet at 0.35.
Pellets fired at 1200°C didn’t meet the recommended CCS
value of 150 kg/pellet. Porosity decreased with an increase
in basicity, with desirable levels of 18–25% in pellets with
basicity of 0.20 to 0.25.
The induration studies at 20 min also found that a
basicity of 0.25 and a temperature of 1250°C achieved the
desired CCS and porosity of pellets (Figure 15). Pellets fired
at 1250 °C with basicity of 0.35 demonstrated a significant
improvement in CCS, reaching a maximum of approxi-
mately 400 kg/pellet. However, porosity decreased as the
basicity increased from 0.05 to 0.35 at all temperatures.
From the previous section, it has been determined that
for obtaining the desired pellet characteristics, a tempera-
ture of 1250 °C, a time of 10 min, and a basicity of 0.25
are the most suitable conditions. To gain deeper insights
into the metallurgical properties of the pellets, tests were
conducted at this optimum condition. The detailed find-
ings are presented in Table 4, which shows that the pellets
have the recommended properties required for the subse-
quent direct reduction process. This information is crucial
for ensuring the quality and efficiency of the entire produc-
tion process.
Table 3. Physical properties of the developed green pellets
Properties Recommended
Basicity
0.05 0.10 0.15 0.20 0.25 0.30 0.35
Moisture (%)8–10 20.1 19.5 21.0 22.0 21.4 22.1 21.5
Average Drop Number 6.0 31.0 33.0 33.0 37.0 41.0 49.0 55.0
Green Compressive Strength (kg/pellet) 1 1.5 1.7 1.8 2.0 2.2 2.3 2.3
Figure 14. CCS (A) &Porosity (B) vs Basicity at 1200 °C, 1250 °C and 1300 °C (10 min)
Table 4. Metallurgical properties of the fired pellets under
optimum conditions
Parameters
Present
Study Recommended
CCS, kg/pellet 170–180 150, average
Porosity, %18–21 18–25
Tumbler Index, %97.5–98 92
Abrasion Index, %2–2.4 5
Reduction Degradation
Index, %
2.5–3 25
Reducibility Index, %75–80 60