The Sintering Characteristics of Mixing SiO2 with Calcium Ferrite at 1473 K (1200 °C)

Ding, Xiang; Guo, Xing‐Min

doi:10.1007/s11663-015-0348-4

Cited by 24 publications

(10 citation statements)

References 22 publications

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“…Scarlett et al 19) and Webster et al 1) had reported that the presence of Al 2 O 3 can expand the stability range and lower the beginning temperature of the SFCA formation. One of authors [20][21][22] had investigated the effect of SiO 2 on formation of SFC (silico-ferrite of calcium), which is the precursor phase of SFCA, suggesting that Si 4 + can replace Fe 3 + located on octahedral layers of the binary calcium ferrite to form SFC. The reaction between CaFe 2 O 4 and the SFC depresses the melting temperature.…”

Section: O 7 )mentioning

confidence: 99%

Effect of MgO on Formation and Crystallization Behaviors of Calcium Ferrite during Heating and Cooling Processes

et al. 2018

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MgO is one of essential component in blast furnace slag for improving the fluidity and desulfurization. Generally it is added via sintering process. It has been also proved in practice that the addition of MgO affects the quality of sinter significantly. However, the effect of MgO on formation and crystallization behaviors of calcium ferrite in sintering had been scarcely discussed. In this work, the crystalline products in CaO-Fe 2 O 3 system with different content of MgO were identified by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). In order to follow the reactions during heating and cooling, differential scanning calorimetry (DSC) was also conducted. It was found that addition of MgO restrained the formation of CaFe 2 O 4 leading to the decrease in content of original melt during sintering process. The contents of Ca 2 Fe 2 O 5 and solid solution of magnetite (magnetite s.s) were increased and the crystallization of Ca 2 Fe 2 O 5 was also promoted with increasing MgO. Compared with forming Ca 2 Fe 2 O 5 , addition of MgO facilitated to form magnetite s.s. Content of initial liquid phase was decreased with increasing MgO, whereas new liquid phase was generated at 1 609 K when the content of MgO exceeded 7 mass%, due to the reaction between Ca 2 Fe 2 O 5 and magnetite.

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Section: O 7 )mentioning

confidence: 99%

Effect of MgO on Formation and Crystallization Behaviors of Calcium Ferrite during Heating and Cooling Processes

et al. 2018

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“…The melting point of the initial minerals in the sintering raw material is too high to melt at sintering temperature. However, the solid state reaction alone is not enough to give the sinter a proper bonding strength . So intensifying mass transfer between particles by producing low melting point minerals in solid state reactions is of great significance to improve the quality of sinter and conserve energy.…”

Section: Introductionmentioning

confidence: 99%

Effect of Alumina on Liquid Phase Formation in Sintering Process of Iron Ore Fines

Guo

2019

steel research int.

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The formation of liquid phase is of great significance for improving the quality of high basicity sinter which is widely used as raw materials in blast furnace ironmaking. As an important component of gangue in iron ore, alumina affects the amount of liquid phase by influencing the formation of calcium ferrites-bonding phase. In this work, the hematite solid solution with aluminum (H ss ) was prepared and sintered with CaO to investigate the effect of alumina on liquid phase formation in sintering process of iron ore fines. Three homogeneous phases of CaFe 2 O 4 (CF), Ca 2 Fe 15.57 O 25.56 (CF 3.9 ), and Ca 3.18 Fe 15.48 Al 1.34 O 28 (CFA) are prepared to determine the melting temperature by using DSC method. XRD, SEM-EDS, and optical microscope are used to characterize the change of mineral and microstructure of sintered samples. The results show that an Fe-rich calcium ferrite CF 3.9 is produced above 1200 C in Fe 2 O 3 -CaO binary system. The liquid phase formation temperature can be reduced to 1206 C when CF 3.9 and CF coexist. The ternary calcium ferrite CFA, which has a eutectic temperature of 1201 C with CF, is generated above 990 C in Fe 2 O 3 -CaO-Al 2 O 3 ternary system. The formation of liquid phase is promoted by adding alumina in moderation through changing the mass ratio of CF to CFA, and the largest amount of liquid phase is produced when the ratio is 8:2.

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“…Silica content influences the phase composition and bonding phase mass of SFCA because of their low melting point [3,4], high mechanical strength [5][6][7][8], and SFCA is an important part of the point of view of saving cost and energy from low temperature sinter. SiO 2 -Fe 2 O 3 -CaO (SFC) is believed to be the transition phase during the SFCA formation process and has been widely investigated [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Effect of SiO2 on the Mechanical Property and Reduction of Calcium Ferrite

Yang

Wang

et al. 2019

Metals

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SiO 2 -Fe 2 O 3 -CaO (SFC) is believed to be the transition phase during the SiO 2 -Fe 2 O 3 -CaO-Al 2 O 3 (SFCA) formation process. The effect of SiO 2 on the mechanical property and reduction of the CaO-Fe 2 O 3 -SiO 2 system was inspected in this study. Experiments were carried out under air at 1200 • C with different amounts of SiO 2 mixed with Fe 2 O 3 and CaO. The mechanical properties and reduction of samples were studied. Results indicate that the hardness of samples gradually increases with the increase of SFC content. That may be caused by SiO 2 solid solution in calcium ferrite. The larger the amount and smaller size of acicular calcium ferrites in samples, the greater the fracture toughness. The solid solution of SiO 2 in calcium ferrite is beneficial to decrease the initial reduction temperature. The apparent activation energy values of the samples with the different content of SiO 2 from 0% to 5% are 167. 23, 84.36, 87.90, 96.02, 92.44 and 107.83 kJ·mol −1 , respectively. The microstructure of lump samples after reduction consists of four phases, i.e., CF (CaFe 2 O 4 ), SFC, calcio-wüstite (CW) and Fe. It was not difficult to find the Fe in the samples reduced from CW. Scanning electron micrograph images have revealed that the acicular-like calcium ferrites are more easily reduced than the platy-like ones.

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The Sintering Characteristics of Mixing SiO2 with Calcium Ferrite at 1473 K (1200 °C)

Cited by 24 publications

References 22 publications

Effect of MgO on Formation and Crystallization Behaviors of Calcium Ferrite during Heating and Cooling Processes

Effect of MgO on Formation and Crystallization Behaviors of Calcium Ferrite during Heating and Cooling Processes

Effect of Alumina on Liquid Phase Formation in Sintering Process of Iron Ore Fines

Effect of SiO2 on the Mechanical Property and Reduction of Calcium Ferrite

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