Jian-guang Lu, Chen-chen Lan, Qing Lyu, Shu-hui Zhang, and Jian-ning Sun, Effects of SiO2 on the preparation and metallurgical properties of acid oxidized pellets, Int. J. Miner. Metall. Mater., 28(2021), No. 4, pp.629-636. https://dx.doi.org/10.1007/s12613-020-2236-4
Cite this article as:
Jian-guang Lu, Chen-chen Lan, Qing Lyu, Shu-hui Zhang, and Jian-ning Sun, Effects of SiO2 on the preparation and metallurgical properties of acid oxidized pellets, Int. J. Miner. Metall. Mater., 28(2021), No. 4, pp.629-636. https://dx.doi.org/10.1007/s12613-020-2236-4
Jian-guang Lu, Chen-chen Lan, Qing Lyu, Shu-hui Zhang, and Jian-ning Sun, Effects of SiO2 on the preparation and metallurgical properties of acid oxidized pellets, Int. J. Miner. Metall. Mater., 28(2021), No. 4, pp.629-636. https://dx.doi.org/10.1007/s12613-020-2236-4
Cite this article as:
Jian-guang Lu, Chen-chen Lan, Qing Lyu, Shu-hui Zhang, and Jian-ning Sun, Effects of SiO2 on the preparation and metallurgical properties of acid oxidized pellets, Int. J. Miner. Metall. Mater., 28(2021), No. 4, pp.629-636. https://dx.doi.org/10.1007/s12613-020-2236-4
School of Metallurgy, Northeastern University, Shenyang 110819, China
2)
College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, China
3)
HBIS Group Hansteel Company, Handan 05600, China
Funds: This work was financially supported by the Key Program of the National Natural Science Foundation of China (No. U1360205) and the Natural Science Foundation of Hebei Province of China (No. E2019209424)
The effects of SiO2 content on the preparation process and metallurgical properties of acid oxidized pellets, including compressive strength, reduction, and softening–melting behaviors, were systematically investigated. Mineralogical structures, elemental distribution, and pore size distribution were varied to analyze the mechanism of the effects. The results show that with an increase in SiO2 content from 3.51wt% to 7.18wt%, compressive strength decreases from 3150 N/pellet to 2100 N/pellet and reducibility decreases from 76.5% to 71.4%. The microstructure showed that pellets with high SiO2 content contained more magnetite in the mineralogical structures. Additionally, some liquid phases appeared, which hindered the continuous crystallization of hematite. Also, the softening–melting properties of the pellets clearly deteriorated as the SiO2 content increased. With increasing SiO2 content, the temperature range of the softening–melting zone decreased, and the maximum differential pressure and the comprehensive permeability index increased significantly. When acid oxidized pellets are used as the raw materials for blast furnace smelting, it should be combined with high basicity sinters to improve the softening–melting behaviors of the comprehensive charge.
Increasing awareness of the need to protect the environment has increased the demand for environmental protection in iron and steel enterprises, especially in the ironmaking processes, for which low pollution and low energy consumption technologies are desired. In the ironmaking process, sintering production is usually classified as a process with high energy consumption and pollutant emission. A large number of harmful substances such as SO2, NOx, dioxin, and dust are generated during the sintering process [1–6]. By comparison, the energy consumption in the pelletizing process is only 50% of that in the sintering process, and with reduced energy consumption, pollution emission is also greatly reduced, which is great advantage of the pelletizing process [7–8]. The iron grade of pellets is 6% to 7% higher than that of sinters, resulting in a lower slag : iron ratio and a lower fuel ratio in the blast furnace (BF) when pellets are used as the charge. In general, when the grade of iron ore charged into BF increases by 1%, the fuel ratio decreases by 1.5%, the hot metal production increases by 2.5%, and the slag ratio decreases by 1.5% [9–10]. Therefore, increasing pellet utilization plays an important role in energy savings and the reduction of pollutant emissions in ironmaking systems.
Currently, increasing effects have been recorded in pellet production, specifically, through improvement of the MgO content and the basicity of the pellets. Some researches [11–15] reported that adding a certain amount of MgO to pellets inhibits the oxidation of Fe3O4 to Fe2O3. This results in incomplete oxidation of Fe3O4 and hinders the recrystallization of Fe2O3, which is not conducive to the densification of the pellets. It also leads to incomplete consolidation of pellets during roasting. Gao et al. [16–17] studied the effect of MgO additives on the properties of pellets, and they found that an increase in MgO content in pellets could improve reducibility, reduction–swelling properties, low-temperature reduction degradation, and strength after reduction. When the MgO content was increased from 0wt% to 2.0wt%, the compressive strength of the pellets decreased as the porosity and pore size increased, and the oxidation of Fe3O4 was inhibited. Volume shrinkage of the pellets decreased, densification was incomplete, and porosity increased. With an increase in the pellets' basicity, CaO content increased continuously, which promoted the growth of hematite crystals [18–21]. During the pellet roasting process, CaO reacted with Fe2O3 to form low-melting-point calcium ferrite compounds (Cao·Fe2O3). These compounds could accelerate the diffusion and enhance the migration of Mg2+, and increase the mineralization of MgO. However, with a continuous increase in CaO content, liquid phase calcium ferrite further increased, which hindered the crystallization of Fe2O3 grains and reduced the strength of the pellets [22–23].
SiO2 has an important effect on the metallurgical properties of pellets. Therefore, it influences the BF operation. In China, pellets are generally acidic, and the SiO2 content is generally higher than 3.5wt%. Currently, the effect of SiO2 on the metallurgical properties of pellets is prevalent in magnesium-based and fluxed pellets. For example, Li et al. [24] studied the effect of SiO2 content on the compressive strength of magnesia acid pellets, and they found that the compressive strength of the pellets decreased with an increase in the SiO2 content, decreasing by 22.72 N/pellet with a 0.1% increase in SiO2 content. Based on this, the mechanism by which SiO2 affects the metallurgical properties of acid magnetite pellets during consolidation was studied under the conditions of natural basicity and natural MgO content.
In this study, the effects of SiO2 content on the compressive strength, reducibility, reduction degradation, reduction–swelling, and softening–melting property of acid oxide pellets were systematically investigated. The mechanism of the effects was analyzed via scanning electron microscopy–energy-dispersive spectrometry (SEM–EDS). These investigations would provide theoretical guidance for the control of SiO2 content in the production of acid magnetite pellets.
2.
Experimental
2.1
Raw materials
Pellets of different SiO2 contents were prepared with high- and low-silicon iron ore powders. Bentonite was used as the pelletizing binder, and its content was fixed at 2wt%. The pellets were prepared using a disk pelletizing machine. The rotating speed was maintained at 20 r/min with an inclination angle of 45°. The pelletizing water content was 8.0wt%, and the pelletizing time was 12 min. The green pellets were preheated and roasted in horizontal tube furnaces 600 mm in width and 50 mm in diameter. The obtained green balls were preheated at 900°C for 15 min and roasted at 1250°C for 20 min. During the preheating and roasting processes, air was pumped into the reaction system at a flow rate of 5 L/min. The ore-blending scheme and green quality of the pellets of differing SiO2 content are listed in Table 1. The theoretical chemical compositions of the various pellets are listed in Table 2. The proximate analysis of coke used in this paper is listed in Table 3.
Table
1.
Ore-blending scheme and green quality of pellets of differing SiO2 content
Pellet
Ore-blending scheme / wt%
Green pellet quality
Low-silicon iron ore powder
High silicon iron ore powder
Bentonite
Drop strength
Compressive strength / (N per pellet)
P1
78
20
2
5.2
12.37
P2
57
41
2
4.9
11.9
P3
36
62
2
5
11.14
P4
14
84
2
5.6
10.85
P5
0
98
2
5.1
11.29
Note: Drop strength represents as the number of times by free-dropping from a height of 0.5 m until the pellet is broken.
According to the standard of “Iron-ore pellets for BF and direct reduction feedstocks-determination of the crushing strength” (GB/T 14201-2018), an automatic pellet compressive strength tester was used to measure the compressive strength of the pellets. Each group of data measured 20 pellets (particle size of 10.0–12.5 mm) after roasting and cooling. The minimum and maximum values of the group of data were discarded, and the average value of the remaining data was recorded as the compressive strength of the pellets.
2.2.2
Reduction index
According to the “Iron ores determination of reducibility” standard (GB/T 13241-2017), the reduction property of the pellets was tested. 500-g pellet samples with particle sizes of 10.0–12.5 mm were reduced at a constant temperature in a medium-temperature furnace. The reduction tests were carried out using a CO–H2 mixed gas at a flow rate of 15 L/min, and the reaction temperature was maintained at 900°C for 3 h. The reduction index (RI) was calculated using the equation:
RI=(0.11W10.43W2+m0−mtm0×0.43W2)×100%
(1)
where m0 is the mass of the sample before reduction; mt the mass of the sample after reduction for t min; W1 and W2 are the contents of FeO and total iron in the sample before the experiment, respectively.
2.2.3
Low temperature reduction degradation index
According to the standard of “Iron ores-low-temperature degradation test method using cold tumbling after static reduction” (GB/T 13242-91), we performed a low-temperature reduction degradation experiment for the pellets. 500-g pellet samples with particle sizes of 10.0–12.5 mm were reduced at a constant temperature of 500°C for 1 h. The reduction gas was a mixture of CO2, CO, and N2 with a volume ratio of 1:1:3. When the reduction experiment was completed, the sample was cooled to room temperature under a pure N2 atmosphere. After weighing, it was loaded into a drum of dimensions ϕ130 mm × 200 mm. The drum turned to 300 r at a speed of 10 r/min. Thereafter, the sample was taken out and then screened and separated using a 3.15-mm-square hole sieve. The mass fraction of the sample larger than 3.15 mm was expressed as RDI+3.15:
RDI+3.15=m3m2×100%
(2)
where m2 is the mass of the sample after reduction but before loading into the drum and m3 is the mass of the sample left on the sieve.
2.2.4
Reduction–swelling index
According to the standard of “Iron-ore pellets determination of relative free-swelling index” (GB/T 13240-91), we determined the reductive swelling property of the pellets. Eighteen seamless pellets (10.0–12.5 mm) were randomly selected, and six pellets in each layer were placed in a container for the reduction test. The test was performed at 900°C for 1 h. The reduction gas was a mixture of CO and N2 (volume ratio of CO : N2 = 3:7) and was pumped at 15 L/min. After reduction, the pellets were cooled under an N2 atmosphere and taken out of the reaction tube to determine their volume. The reduction–swelling index (RSI) was calculated thusly:
RSI=V0−V1V0×100%
(3)
where V0 and V1 are the volumes of the pellets before and after reduction, respectively.
2.2.5
Softening–melting properties
Coke and the pellets were separately packed into a crucible and stacked thusly: 20 mm coke, 50 mm pellets, and 20 mm coke. According to the standard of “Iron ores-method for determination of iron reduction softening dripping performance under loads” (GB/T 34211-2017), the heating rate was 10°C/min at temperatures below 900°C and 2°C/min at 900–1100°C. Above 1100°C, a heating rate of 5°C/min was employed until the burden dripped. The entire heating process was completed under an N2–CO atmosphere (5 L/min), with a CO : N2 volume ratio of 3:7. During the experiment, the pressure difference between the upper and the lower burden layers was recorded in real time. The larger the comprehensive permeability index (S), the worse the softening–melting properties of the pellets.
S=∫TdTs(ΔPT−ΔPS)dT
(4)
where ΔPT is the pressure difference at temperature T, ΔPS is the pressure difference at the temperature Ts, Ts is softening temperature, and Td deformation temperature.
3.
Results and discussion
3.1
Effect of SiO2 content on the metallurgical properties of the pellets
The effects of SiO2 content on the compressive strength, reducibility, reduction degradation, and reduction–swelling of the pellets are shown in Fig. 1. As the SiO2 content increased, the compressive strength decreased gradually. When SiO2 content is 3.51wt%, the compressive strength is 3125 N/pellet. When SiO2 content is 7.18wt%, the compressive strength decreases to 2059 N/pellet, with a large decreasing range of 1066 N/pellet. The main reason is that with the increase in SiO2 content, silicate minerals in the pellets increase, and the excessive liquid phase can destroy the compressive strength of the pellets. Due to the sufficient oxidation of the pellets, the appropriate liquid phase plays an important role in the consolidation of the pellet when the roasting temperature is not high. When the preheat oxidation is sufficient, the pellet strength is mainly influenced by the solid crystal, and the liquid phase amount and pellet strength are inversely related. In addition, too much silicate mineral hinders the crystallization and recrystallization of Fe2O3 grains in pellets, also reducing the compressive strength of the pellets. The compressive strength of the various samples met the quality requirement for pellets for BF. Meanwhile, with increasing SiO2 content, the RI value of the various samples decreased gradually. When SiO2 content was 3.51wt%, the RI value was 76.42%, and as SiO2 content increased to 7.18wt%, the RI value decreased to 71.14%, a 5.28% decrease. A higher reduction performance of the pellets improves the indirect reduction of BF, which could reduce fuel consumption in the ironmaking process. With increasing SiO2 content of the pellets, RDI+3.15 increased. When SiO2 content was in the range of 3.5wt%–7.18wt%, RDI+3.15 remained >95%, indicating that the pellets were insignificantly reduced at low temperatures and the strength remained constant. This would improve the permeability of the block zone in BF operations. The improvement in RDI+3.15 with increasing SiO2 content is mainly due to an increase in SiO2 content promoting the formation of the silicate liquid phase, such as olivine, and a large amount of the formed liquid phase permeating along the grain boundaries to include the Fe2O3 grains. This reduces the expansion rate of the pellets during the reduction process and thus, improves the reduction degradation performance. With increasing SiO2 content, the RSI decreased gradually. When SiO2 content was 3.51wt%, RSI was 19.73%, decreasing to 13.81% (an approximate 5.92% decrease) as SiO2 content increased to 7.18wt%. The main reason for this is that, with an increase in SiO2 content, the connection between the slag phases is strengthened, preventing excessive expansion of Fe2O3 as it is reduced to Fe3O4 and reducing the reduction expansion index of the pellets. When SiO2 content was in the range of 3.5wt%–7.18wt%, RSI was <20%, which had little effect on the stability and smooth running of BF.
Fig.
1.
Effect of w(SiO2) on CS, RI, RDI+3.15, and RSI. CS—Compressive strength; RI—Reduction index; RDI+3.15— Low temperature reduction degradation index; RSI—Reduction–swelling index.
Fig. 2 shows the variation in the softening–melting temperature range (ΔT) for the pellets of differing SiO2 content. As SiO2 content increased in pellets, the initial softening temperature (T10%) of the pellets (i.e., the temperature at the burden shrinkage of 10%) varied little, whereas the temperature at which the burden begins to drip (Td) decreased greatly, which caused the ΔT of the pellets to decrease. When SiO2 content increased from 3.51wt% to 7.18wt%, Td decreased from 1402 to 1317°C and ΔT decreased by 88°C (from 207 to 119°C). The main reason is that an increase in SiO2 content leads to a proportional increase in the low-melting-point materials in the primary slag, reducing the melting temperature of the primary slag, thereby decreasing the dropping temperature.
Fig.
2.
Effect of w(SiO2) on the softening–melting temperature of pellets.
Fig. 3 shows the maximum pressure difference (ΔPmax) and comprehensive permeability index (S) of the pellets of differing SiO2 content during the softening–melting process. As SiO2 content increased, the ΔPmax and S of the pellets increased significantly. When SiO2 content increased from 3.51wt% to 7.18wt%, ΔPmax increased by 15.95 kPa (from 4.05 to 20.00 kPa) and S increased by 443.18 kPa·°C (from 233.53 to 676.71 kPa·°C). These show that with an increase in SiO2 content, the permeability of the burden decreases significantly, thus increasing the amount of primary slag, which worsens the permeability of the softening–melting zone [25].
Fig.
3.
Effect of SiO2 content on the pressure difference (ΔPmax) and S of pellets
The consolidation process for oxidized magnetite pellets mainly depends on the crystal bridge connection. When magnetite pellets are calcined and consolidated in an oxidizing atmosphere, Fe3O4 in the pellets gradually oxidizes and Fe2O3 microcrystals are formed. The newly formed Fe2O3 microcrystals have high dispersion ability, which causes them grow and connect with other adjacent microcrystals. With an increase in the oxidation temperature, all Fe3O4 in the magnetite pellets oxidizes into Fe2O3, causing the separated microcrystals to gradually connect into a piece of hematite crystal. The quality of the crystal bridge connection directly affects the compressive strength of the pellets [26–28]. The mineralogical structures of the pellets of differing SiO2 content are shown in Fig. 4.
Image-Pro Plus software was used to put forward and process the color of the mineral facies graphics. According to statistical analysis of the different color areas on the graphics, when the SiO2 content was 3.51wt%, the areas corresponding to hematite and magnetite were 52.25% and 2.11%, respectively. When SiO2 content increased to 5.49wt%, the area corresponding to hematite decreased to 49.55% and that of magnetite increased to 7.40%. When SiO2 content increased to 7.18wt%, the hematite and magnetite areas further decreased to 38.12% and increased to 12.27%, respectively. These indicate that an increase in SiO2 content in pellets hinders the oxidation of magnetite and the continuous crystallization of hematite, reducing the compressive strength and reducibility of the pellets. With an increase in silicon oxide content, the production of olivine gradually increases, but the strength and reduction of olivine are relatively low, which leads to a decrease in the strength and reducibility of the pellets. Meanwhile, FeO reacts with SiO2 to form 2FeO·SiO2 with a melting point of 1205°C. This can further react with FeO and SiO2 to form compounds with lower melting points, such as 2FeO·SiO2–Fe3O4, 2FeO·SiO2–FeO, and 2FeO·SiO2–SiO2, having melting points of 1142, 1177, and 1178°C, respectively. If there is a large amount of SiO2 in the pellets, the amount of liquid phase would increase and strength would decrease.
Fig.
4.
Mineralogical structures of pellets with different SiO2 contents: (a) 3.51wt%; (b) 5.49wt%; (c) 7.18wt%; (d–f) color extraction from different mineralogical structures of (a–c). H—Hematite; M—Magnetite; P—Pores; L—Liquid.
The microstructure and elemental distribution of the pellets with different SiO2 contents are shown in Fig. 5 and Table 4. The presence of SiO2 hindered the continuous crystallization of iron-bearing phases, and a portion of SiO2 and iron oxide formed liquid phases and agglomerates, which further hindered the continuous crystal consolidation of the pellets. With an increase in SiO2 content, the blocking effect of SiO2 on the intergranular consolidation of the pellets also increased.
Fig.
5.
SEM and elemental distribution diagrams of pellets under different SiO2 contents: (a) 3.51wt%; (b) 5.49wt%; (c) 7.18wt%.
The pore size distribution and porosity of the pellets with different SiO2 content are shown in Fig. 6. When the SiO2 content was 3.51wt%, the pore size of the pellets was mainly 2–6 μm; there were only a few pores with diameters >6 μm. The overall porosity of the pellets was 18.48%. As SiO2 content increased to 5.49%, pores with diameters of 2–4 μm decreased greatly, whereas those of 4–6 μm changed little. The overall porosity of the pellets also decreased to 15.25% (a 3.23% decrease). This is attributed to the increase in SiO2 content, which promotes the formation of a liquid phase in pellets. The liquid phase fills into the pores, forming closed pores, and the degree of densification of the pellets increases [29]. This phenomenon deteriorates the dynamic conditions of the reduction process of pellets as well as their reducibility. The densification of pellets is beneficial to the compressive strength; however, the liquid produced by the pellets has a great blocking effect on the continuous crystallization of Fe2O3. Under comprehensive loading, the compressive strength of the pellets still decreases. Due to the increase in the degree of densification, the amount of reducing gas diffused into the pellets decreases and the resistance to the formation of iron whiskers increases, which reduces the reduction−swelling rate of the pellets.
Fig.
6.
Pore size distribution of pellets with SiO2 contents of (a) 3.51wt%, (b) 5.49wt% and (c) 7.18wt%; (d) relationship between porosity of pellets and SiO2 content.
When SiO2 content increased from 5.49wt% to 7.18wt%, pores with sizes of 2–4 μm increased greatly and those of 4–6 μm decreased, while pores larger than 6 μm increased to a certain extent. The pore size distribution of the pellets was uneven, and the overall porosity of the pellets increased to 17.20%, which is a 1.95% increase relative to those pellets at 5.49wt% SiO2 content. The micro-pore inside the pellet decreases and the macro-pore and penetration pore structures increase significantly. The main reason is that, with an increase in SiO2 content, the shapes of the pores become irregular, and an increase in free SiO2 leads to an increase in porosity. Meanwhile, silicate minerals exist as flocs, and the cracks between silicates increase, resulting in a significant decrease in compressive strength [29]. Due to the increase in the FeO·SiO2 content of the liquid phase, the reducibility of the composite decreases and the reduction–swelling property improves.
4.
Conclusions
In this study, the effect of SiO2 content on the preparation process and properties of magnate pellets has been studied. From the results, the following conclusions could be drawn.
(1) With an increase in SiO2 content from 3.51wt% to 7.18wt%, the compressive strength decreases from 3150 N/pellet to 2100 N/pellet, and the reducibility decreases from 76.5% to 71.4%. The reduction degradation property changes slightly, but the reduction–swelling property of pellets is improved.
(2) SiO2 content has a clear effect on the softening–melting properties of pellets. The starting drop temperature is reduced from 1402 to 1317°C, and the temperature range of the softening–melting zone of pellets decreases from 207 to 119°C with an increase in SiO2 content from 3.51wt% to 7.18wt%. Both the maximum pressure difference and the comprehensive permeability index of the softening–melting zone increase significantly.
(3) The presence of silicate minerals in pellets hinders the continuous crystallization of hematite, and a liquid phase gradually appears in the mineralogical structures as SiO2 content increases. This has a major effect on the metallurgical properties of acid oxidized pellets.
Acknowledgements
This work was financially supported by the Key Program of the National Natural Science Foundation of China (No. U1360205) and the Natural Science Foundation of Hebei Province of China (No. E2019209424).
Y.G. Chen, Z.C. Guo, and Z. Wang, Influence of CeO2 on NOx emission during iron ore sintering, Fuel Process. Technol., 90(2009), No. 7-8, p. 933. DOI: 10.1016/j.fuproc.2009.03.021
C.C. Yang, D.Q. Zhu, and J. Pan, Some basic properties of granules from ore blends consisting of ultrafine magnetite and hematite ores, Int. J. Miner. Metall. Mater., 26(2019), No. 8, p. 953. DOI: 10.1007/s12613-019-1824-7
H. Zhou, M.X. Zhou, Z.H. Liu, M. Cheng, and J.Z. Chen, Modeling NOx emission of coke combustion in ore sintering process and its experimental validation, Fuel, 179(2016), p. 322. DOI: 10.1016/j.fuel.2016.03.098
H. Zhou, Z.H. Liu, M. Cheng, M.X. Zhou, and R.P. Liu, Influence of coke combustion on NOx emission during iron ore sintering, Energy Fuels, 29(2015), No. 2, p. 974. DOI: 10.1021/ef502524y
A.B. Kotta, A. Patra, M. Kumar, and S.K. Karak, Effect of molasses binder on the physical and mechanical properties of iron ore pellets, Int. J. Miner. Metall. Mater., 26(2019), No. 1, p. 41. DOI: 10.1007/s12613-019-1708-x
T.C. Ooi, D. Thompson, D.R. Anderson, R. Fisher, T. Fray, and M. Zandi, The effect of charcoal combustion on iron-ore sintering performance and emission of persistent organic pollutants, Combust. Flame, 158(2011), No. 5, p. 979. DOI: 10.1016/j.combustflame.2011.01.020
W. Lv, Z.Q. Sun, and Z.J. Su, Life cycle energy consumption and greenhouse gas emissions of iron pelletizing process in China, a case study, J. Cleaner Prod., 233(2019), p. 1314. DOI: 10.1016/j.jclepro.2019.06.180
H.Q. Zhang and J.T. Fu, Oxidation behavior of artificial magnetite pellets, Int. J. Miner. Metall. Mater., 24(2017), No. 6, p. 603. DOI: 10.1007/s12613-017-1442-1
X.X. Huang, X.H. Fan, X.L. Chen, M. Gan, Z.Y. Ji, and R.Y. Zheng, A novel blending principle and optimization model for low-carbon and low-cost sintering in ironmaking process, Powder Technol., 355(2019), p. 629. DOI: 10.1016/j.powtec.2019.07.085
T.J. Yang, J.L. Zhang, and H.W. Guo, Realizing low carbon ironmaking with low consumption, low emission and high efficiency under the guidance of scientific development concept, Ironmaking, 31(2012), No. 4, p. 1.
Q.J. Gao, X. Jiang, G. Wei, and F.M. Shen, Effects of MgO on densification and consolidation of oxidized pellets, J. Cent. South Univ., 21(2014), p. 877. DOI: 10.1007/s11771-014-2013-5
Q.J. Gao, F.M. Shen, G. Wei, X. Jiang, and H.Y. Zheng, Effects of MgO containing additive on low-temperature metallurgical properties of oxidized pellet, J. Iron Steel Res. Int., 20(2013), No. 7, p. 25. DOI: 10.1016/S1006-706X(13)60121-1
Q.J. Gao, Y.S. Shen, X. Jiang, H.Y. Zheng, F.M. Shen, and C.S. Liu, Effect of MgO on oxidation process of Fe3O4 in pellets, J. Iron Steel Res. Int., 23(2016), No. 10, p. 1007. DOI: 10.1016/S1006-706X(16)30151-0
Z.C. Huang, Z.G. Han, J.W. Zhou, T. Jiang and X.P. Yang, Influence of MgO on microstructure of fine magnetite concentrate based sinter, Iron Steel, 40(2005), No. 9, p. 16.
D.Q. Zhu, Z.F. Gao, J. Pan, T.J. Chun, and C.C. Yang, Influence of pellet basicity and MgO content on roasting and metallurgical properties of pellets, J. Cent. South Univ. Sci. Technol., 44(2013), No. 10, p. 3963.
Q.J. Gao, G. Wei, Y.B. He, and F.M. Shen, Effect of MgO on compressive strength of pellet, J. Northeast. Univ. Nat. Sci., 34(2013), No. 1, p. 103.
Q.J. Gao, F.M. Shen, X. Jiang, G. Wei, and H.Y. Zheng, Gas-solid reduction kinetic model of MgO-fluxed pellets, Int. J. Miner. Metall. Mater., 21(2014), No. 1, p. 12. DOI: 10.1007/s12613-014-0859-z
T. Umadevi, P. Kumar, N.F. Lobo, M. Prabhu, P.C. Mahapatra, and M. Ranjan, Influence of pellet basicity (CaO/SiO2) on iron ore pellet properties and microstructure, ISIJ Int., 51(2011), No. 1, p. 14. DOI: 10.2355/isijinternational.51.14
D.Q. Zhu, T.J. Chun, J. Pan, and J.L. Zhang, Influence of basicity and MgO content on metallurgical performances of Brazilian specularite pellets, Int. J. Miner. Process., 125(2013), p. 51. DOI: 10.1016/j.minpro.2013.09.008
X.H. Fan, L.B. Xie, M. Gan, X.L. Chen, and L.S. Yuan, Roasting characteristics of magnesium pellets and mechanism of strengthening concretion, J. Cent. South Univ. Sci. Technol., 44(2013), No. 2, p. 449.
X.H. Fan, M. Gan, T. Jiang, L.S. Yuan, and X.L. Chen, Influence of flux additives on iron ore oxidized pellets, J. Cent. South Univ., 17(2010), No. 4, p. 732. DOI: 10.1007/s11771-010-0548-7
X.F. Cai and T.L. Tian, Effect of basicity on strength high magnesia basicity pellet, Multipurpose Util. Miner. Resour., 4(2014), p. 48.
S. Dwarapudi, T.K. Ghosh, A. Shankar, V. Tathavadkar V, D. Bhattacharjee, and R. Venugopal, Effect of pellet basicity and MgO content on the quality and microstructure of hematite pellets, Int. J. Miner. Process., 99(2011), No. 1-4, p. 43. DOI: 10.1016/j.minpro.2011.03.004
J. Li, C.C Han, A.M. Yang, W.X. Liu, Y.Z. Zhang, and L.J. Liu, Effect of SiO2 on quality of magnesian acid pellets, J. Iron Steel Res., 29(2017), No. 11, p. 872.
C.C. Lan, S.H. Zhang, X.J. Liu, Q. Lyu, and M.F. Jiang, Change and mechanism analysis of the softening-melting behavior of the iron-bearing burden in a hydrogen-rich blast furnace, Int. J. Hydrogen Energy, 45(2020), No. 28, p. 14255. DOI: 10.1016/j.ijhydene.2020.03.143
J. Tang, M.S. Chu, C. Feng, F. Li, and Z.G. Liu, Phases transition and consolidation mechanism of high chromium vanadium-titanium magnetite pellet by oxidation process, High Temp. Mater. Processes, 35(2016), No. 7, p. 729. DOI: 10.1515/htmp-2015-0067
H. Papacek, Quality aspects in pellettising of iron ores, Steel Technol. Int., 25(1993), No. 7, p. 227.
Y.M. Chen and J. Li, Crystal rule of Fe2O3 in oxidized pellet, J. Cent. South Univ. Sci. Technol., 38(2007), No. 1, p. 70.
Y.P. Zhang, J.Y. Fu, T. Jiang, and Y.B. Yang, The Influence of gangue contents on properties of pellet, Sintering Pelletizing, 27(2002), No. 4, p. 11.
Haoyu Cai, Jianliang Zhang, Zhengjian Liu, et al. Study on the Effects of Mg–Si Gangue Compositions within Magnetite on Iron Oxide Crystallization during Pellet Roasting. steel research international, 2025.
DOI:10.1002/srin.202401069
2.
Bohua Li, Deqing Zhu, Zhengqi Guo, et al. Impact of SiO2 Content on the Hydrogen-Based Direct Reduction of Acidic High-Grade Fired Hematite Pellets. Journal of Sustainable Metallurgy, 2025.
DOI:10.1007/s40831-025-01026-1
3.
Qingyue Chen, Jian Pan, Zhengqi Guo, et al. Optimization of four-component furnace burdens with hydrogen-reduced metallized pellets based on blast furnace performance. International Journal of Hydrogen Energy, 2025, 100: 596.
DOI:10.1016/j.ijhydene.2024.12.218
4.
Yufeng Guo, Jinlai Zhang, Shuai Wang, et al. Diffusion and reaction mechanism of limestone and quartz in fluxed iron ore pellet roasting process. International Journal of Minerals, Metallurgy and Materials, 2024, 31(3): 485.
DOI:10.1007/s12613-023-2739-x
5.
Zheng-jian Liu, Li-ming Ma, Jian-liang Zhang, et al. Study of slag formation behavior in iron ore pellets based on thermodynamic calculations and experiments. Calphad, 2024, 87: 102729.
DOI:10.1016/j.calphad.2024.102729
6.
Yao-zu Wang, Jian-liang Zhang, Qiang Cheng, et al. Interface interaction between SiO2 and magnetite under high temperature: particle migration and inhibition mechanism. Journal of Iron and Steel Research International, 2024, 31(3): 561.
DOI:10.1007/s42243-023-01078-1
7.
Jian Pan, Chen-mei Tang, Cong-cong Yang, et al. Effect of alumina occurrence form on metallurgical properties of hematite and magnetite pellets. Journal of Iron and Steel Research International, 2024, 31(4): 797.
DOI:10.1007/s42243-023-01066-5
8.
Liming Ma, Jianliang Zhang, Huiqing Jiang, et al. Inhibiting the Accretion in the Coal-Fired Rotary Kiln of High-Silica Iron Ore Pellets Application by Reducing Fines Generation and Liquid Phase Formation. JOM, 2024, 76(8): 4431.
DOI:10.1007/s11837-024-06616-0
9.
Xinyu Jin, Tielei Tian, Huanlong Chen, et al. Effect of SiO2 content in magnesia flux pellets on softening-melting and dripping behavior of comprehensive burden structure. Powder Technology, 2024, 444: 120021.
DOI:10.1016/j.powtec.2024.120021
10.
Yan-biao Chen, Wen-guo Liu, Hao Guo, et al. Exploring a new path of green and efficient utilization of sinter return fine to produce composite pellets. Journal of Iron and Steel Research International, 2024, 31(7): 1610.
DOI:10.1007/s42243-023-01171-5
11.
Kaikai Bai, Weidong Chen, Yuzhu Pan. Consolidation Behaviors of Magnesium Acid Pellet Produced by Serpentine and High-Silicon Iron Ore Concentrate. JOM, 2023, 75(5): 1450.
DOI:10.1007/s11837-022-05506-7
12.
Jinge Feng, Jue Tang, Mansheng Chu, et al. Effect of Cr2O3 on the Kinetics Mechanism and Microstructure of Pellet During Oxidation Roasting Process. steel research international, 2023, 94(5)
DOI:10.1002/srin.202200735
13.
Liming Ma, Jianliang Zhang, Yaozu Wang, et al. Consolidation behavior of magnesium-containing pellets prepared by high-silica coarse particle magnetite concentrates. Powder Technology, 2023, 427: 118740.
DOI:10.1016/j.powtec.2023.118740
14.
Zhen Li, Jianliang Zhang, Yaozu Wang, et al. Reinforcement of Pellet Consolidation Strength Based on Iron Filings: Microstructural Evolution and Mechanism. steel research international, 2022, 93(10)
DOI:10.1002/srin.202200084
15.
Liming Ma, Jianliang Zhang, Yaozu Wang, et al. Mixed burden softening-melting property optimization based on high-silica fluxed pellets. Powder Technology, 2022, 412: 117979.
DOI:10.1016/j.powtec.2022.117979
16.
Jiwei Bao, Mansheng Chu, Zhenggen Liu, et al. Effect of Iron Carbon Agglomerates on Isothermal Reduction of Pellets with Different Reducibility. steel research international, 2022, 93(4)
DOI:10.1002/srin.202100345
17.
Meng-Bo Dai, Bao-Shu Gu, Zhi-Yong Ruan, et al. Influence of Specific Surface Area on the Strength of Iron Oxidized Pellets. Minerals, 2022, 12(8): 921.
DOI:10.3390/min12080921
18.
Lian-Da Zhao, Hong-Su, Qing-Guo Xue, et al. Characterization of Minerals, Metals, and Materials 2022. The Minerals, Metals & Materials Series,
DOI:10.1007/978-3-030-92373-0_14
Search
DownLoad:
