Cooling Air Velocity on Iron Ore Pellet Performance Based on Experiments and Simulations
<p>Schematic diagram of the cooling experiment for the iron ore pellets ((<b>a</b>) green pellet preparation; (<b>b</b>) drying of green pellets; (<b>c</b>) preheating and roasting; (<b>d</b>) cooling of iron ore pellets).</p> "> Figure 2
<p>Schematic diagram of cooling simulation of the iron ore pellets ((<b>a</b>) schematic diagram of pellet cooling equipment; (<b>b</b>) modelling of iron ore pellet cooling; (<b>c</b>) iron ore pellet cooling baseline model; (<b>d</b>) accuracy calibration of cooling models of iron ore pellet).</p> "> Figure 3
<p>Influence of cooling air velocity on pellet performance ((<b>a</b>) cooling time; (<b>b</b>) pellet strength).</p> "> Figure 4
<p>Light microscopic analysis of pellets at different cooling air velocities ((<b>a</b>–<b>d</b>) 2 m<sup>3</sup>/h; (<b>e</b>–<b>h</b>) 4 m<sup>3</sup>/h; (<b>i</b>–<b>l</b>) 6 m<sup>3</sup>/h).</p> "> Figure 5
<p>SEM-EDS analysis positions of pellets at different cooling air velocities ((<b>a</b>–<b>c</b>) 2 m<sup>3</sup>/h; (<b>d</b>–<b>f</b>) 4 m<sup>3</sup>/h; (<b>g</b>–<b>i</b>) 6 m<sup>3</sup>/h).</p> "> Figure 6
<p>Effect of cooling gas on gas–solid phase temperature ((<b>a</b>) gas temperature; (<b>b</b>) temperature of pellet).</p> "> Figure 7
<p>Effect of cooling air velocity on cooling rate and enthalpy ((<b>a</b>) cooling rate; (<b>b</b>) enthalpy).</p> "> Figure 8
<p>Effect of cooling air velocity on heat recovery.</p> "> Figure 9
<p>Softening–melting characteristics of pellets at different cooling air velocities.</p> ">
Abstract
:1. Introduction
2. Experimental and Simulation
2.1. Raw Materials
2.2. Experimental Procedures
2.3. Simulation Analysis
3. Results and Discussion
3.1. Effect of Varying Cooling Air Velocity on Pellet Solidification Properties
3.1.1. Effect of Varying Cooling Air Velocity on Cooling Time
3.1.2. Effect of Cooling Air Velocity on the Chemical Composition
3.1.3. Effect of Cooling Air Velocity on the Microstructure of Pellets
3.2. Simulation Analysis of Cooling Airflow on Cooling Performance
3.2.1. Effect of Cooling Air Velocity on Gas–Solid Phase Temperature
3.2.2. Effect of Cooling Air Velocity on Cooling Rate and Enthalpy
3.2.3. Effect of Cooling Air Velocity on Heat Recovery
3.3. Effect of Cooling Air Velocity on the Metallurgical Properties of Pellets
4. Conclusions
- (1)
- With the increase in cooling air velocity in the experiment, the cooling rate of the pellets gradually increased, and the unevenness of pellet quality also increased. At an air velocity of 2 m3/h, the average compressive strength of the pellets is 2189 N. When the cooling air velocity is higher, the content of garnet, fayalite, and other low melting point phases increases.
- (2)
- As the simulated air velocity increased, the gas temperature decreased by 41%, and the solid temperature decreased by 31% for a cooling time of 48 min. The cooling rate increases with increasing air velocity. The total enthalpy of the flue gas decreases and then increases with the rise of the air velocity in different annular cooling zones from high to low, which are C-1, C-2, and C-3, respectively. The heat recovery rate increases with increased air velocity, and the heat recovery rate rises to 94.04% with increased air velocity by 1.15 times.
- (3)
- The effect of cooling air velocity on the metallurgical properties of the pellet is mainly reflected in the impact on the formation of low-melting liquid phases such as FeO and iron olivine. With the gradual increase in cooling air velocity, the softening start temperature of the pellet decreased significantly. With the increase in air velocity from 2 m3/h to 6 m3/h, the melting droplet interval decreased from 193 °C to 105 °C, and the melting droplet interval gradually became narrower. With the increase in cooling air velocity, the S value gradually becomes smaller, and the permeability of the adhesion zone increases.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
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Raw Material | Chemical Composition/wt.% | LOI/% | Physical Property | ||||||
---|---|---|---|---|---|---|---|---|---|
TFe | FeO | SiO2 | Al2O3 | CaO | MgO | Below 74 μm Particle Size/% | Blaine Surface Area/(cm2·g−1) | ||
Concentrate-1 | 67.07 | 19.65 | 5.06 | 0.22 | 0.54 | 0.51 | −1.35 | 87.01 | 1837 |
Concentrate-2 | 65.43 | 29.05 | 7.84 | 0.14 | 0.25 | 0.29 | −3.40 | 97.78 | 2188 |
Bentonite | 3.58 | 0.52 | 55.00 | 14.18 | 3.92 | 3.02 | 12.66 | 100 | - |
Cooling Parameters | Cooling 1 Zone (C-1) | Cooling 2 Zone (C-2) | Cooling 3 Zone (C-3) | Cooling 4 Zone (C-4) |
---|---|---|---|---|
Temperature of outlet gas/°C | 1100 | 700 | 350 | 100 |
Cooling area/m2 | 46 | 30 | 46 | 28 |
Cooling times/min | 14.5 | 10 | 14.5 | 9 |
Cooling air velocity/(Nm3·h−1) | 198,000 | 180,000 | 180,000 | 180,000 |
Pellets | Air Velocity/(m3·h−1) | Chemical Composition/wt% | LOI/% | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
TFe | FeO | CaO | SiO2 | MgO | Al2O3 | TiO2 | K2O | Na2O | |||
Pellet-1 | 2 | 64.31 | 0.29 | 0.34 | 6.45 | 0.38 | 0.33 | 0.02 | 0.05 | 0.10 | <0.05 |
Pellet-2 | 4 | 63.75 | 0.46 | 0.33 | 7.31 | 0.38 | 0.36 | 0.02 | 0.03 | 0.07 | <0.05 |
Pellet-3 | 6 | 63.86 | 0.55 | 0.33 | 7.29 | 0.38 | 0.33 | 0.02 | 0.04 | 0.08 | <0.05 |
Spectrum | Chemical Composition/wt% | Mineral Phase | |||||||
---|---|---|---|---|---|---|---|---|---|
Fe | Ca | Si | Mg | Al | K | Na | O | ||
1 | 81.30 | - | - | - | - | - | - | 18.70 | Hematite |
2 | - | - | 62.42 | - | - | - | - | 37.58 | Quartz |
3 | 3.68 | 4.85 | 33.33 | 3.50 | 10.42 | 0.53 | 1.66 | 42.04 | Silicate |
4 | 17.69 | 2.22 | 15.31 | 8.43 | 14.34 | 0.75 | 2.50 | 38.76 | Garnet |
Material | Air Velocity/(m3·h−1) | Metallurgical Properties | |||||||
---|---|---|---|---|---|---|---|---|---|
RI/% | RSI/% | T10/°C | T40/°C | TS/°C | Td/°C | ΔP/kPa | S/kPa·°C | ||
Pellet-1 | 2 | 66.82 | 16.50 | 1123 | 1211 | 1330 | 1523 | 0.348 | 563.64 |
Pellet-2 | 4 | 63.00 | 10.68 | 1048 | 1187 | 1327 | 1522 | 0.370 | 611.52 |
Pellet-3 | 6 | 71.53 | 18.90 | 985 | 1194 | 1412 | 1517 | 0.236 | 191.39 |
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Ma, L.; Zhang, J.; Liu, Z.; Cai, Q.; Hao, L.; Lu, S.; Jiang, H.; Wang, Y. Cooling Air Velocity on Iron Ore Pellet Performance Based on Experiments and Simulations. Metals 2024, 14, 919. https://doi.org/10.3390/met14080919
Ma L, Zhang J, Liu Z, Cai Q, Hao L, Lu S, Jiang H, Wang Y. Cooling Air Velocity on Iron Ore Pellet Performance Based on Experiments and Simulations. Metals. 2024; 14(8):919. https://doi.org/10.3390/met14080919
Chicago/Turabian StyleMa, Liming, Jianliang Zhang, Zhengjian Liu, Qiuye Cai, Liangyuan Hao, Shaofeng Lu, Huiqing Jiang, and Yaozu Wang. 2024. "Cooling Air Velocity on Iron Ore Pellet Performance Based on Experiments and Simulations" Metals 14, no. 8: 919. https://doi.org/10.3390/met14080919