Application of physical methods to the estimation of sinter properties

Mazanek, E; Jasieńska, S.; Obuszko, Zdzislaw

doi:10.1007/bf03378776

Cited by 10 publications

(12 citation statements)

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“…The samples crumble while decomposing and the ferrite is formed. The most stable and the least reducible is Ca2Fe205 [8], which forms at higher temperatures than CaFe204. Both ferrites appear in the intergranular space of calciomagnetites and calciowustites obtained by reduction or synthesis [9,10].…”

Section: Methodsmentioning

confidence: 98%

Application of thermal analysis for the investigation of calcium ferrites

Orewczyk¹

1990

Journal of Thermal Analysis

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Investigations of metallurgical materials such as blast furnace sinters and pellets require the syntheses of the standard phases contained in these materials.Synthetic pure and calcium-doped iron oxides were studied Calcium ferrite phases originated in the intergranular space and strongly affected the reducibility of the sinter, besides haematite and magnetite.Studies of the formation and physicochemical properties of the synthetic calcium ferrites CaFe204 and Ca2Fe2Os, identified in polycrystalline calciomagnetite and caiciowustite samples, are described. ExperimentalThe calcioferrites CaFe204 and Ca2Fe205 have been obtained by thermal dissociation [1][2][3][4][5][6] and following the sintering of stoichiometric CaCO3-Fe203 mixtures at 1150 ~ in air [7]. The products were subjected to microscopic and diffractometric examination and also to microregion spectral analysis.In order to determine the conditions of ferrite formation, thermal analyses were carried out with a Q-15000 Paulik-Paulik-Erdey derivatograph. TG, DTG, DTA analyses were performed in air atmosphere, using 500 mg samples. The temperature was increased at a rate of 7.5 deg/min.As can be seen in Fig. 1, the TG and DTG analyses of a 1:1 molar mixture of in the temperature range 525-880 ~ indicate the complex character of the weight loss (16.4%) process. The process involving a slow increase in the weight loss rate between 325 and 825 ~ turns into the next step with an altered rate up to 880 ~ . The complexity of the weight loss process is confirmed by DTA. There are initially endothermic effects conJohn Wiley & Sons, Limited, Chichester Akadgmiai Kind6, Budapest

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Section: Methodsmentioning

confidence: 98%

Application of thermal analysis for the investigation of calcium ferrites

Orewczyk¹

1990

Journal of Thermal Analysis

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“…Figure 6 clearly describes that the reduction processes of C 2 F, CF, and CF 2 were presented as one-step, two-step, and three-step reactions. Therefore, the The reducibility of the three calcium ferrites was tested in several research, 10,11) all of which except Brunner's result concluded that CF 2 has the best reducibility and C 2 F the worst. The crystal structures [12][13][14] and reduction sequence [15][16][17] of C 2 F, CF, and CF 2 were investigated in previous studies, and the reduction kinetics of C 2 F, CF, and CF 2 were also fully studied in previous research, as shown in Table 2.…”

Section: Reduction Degree and Reduction Ratementioning

confidence: 99%

Reduction of CaO–Fe<sub>2</sub>O<sub>3</sub> Series Compounds by CO

Ding

et al. 2017

ISIJ International

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The isothermal reduction kinetics of C 2 F, CF, and CF 2 by 30% CO and 70% N 2 at 1 123 K (850°C), 1 173 K (900°C), and 1 223 K (950°C) were investigated by thermogravimetric analysis in this study. Results indicated that the maximum reduction degree increased and its corresponding reduction time decreased by the order of C 2 F, CF, and CF 2 . The reduction rate analysis by peak fitting based on the Gauss rule revealed that the C 2 F, CF, and CF 2 reductions were typical one-step, two-step, and three-step reactions, respectively. Fe 3 O 4 to FeO stage overlaps with the following FeO to Fe stage and tends to approach the previous Fe 2 O 3 to Fe 3 O 4 stage in reduction of CaO-Fe 2 O 3 system with an increase in Fe 2 O 3 content. The apparent activation energy of the sample C 2 F, CF, and CF 2 reductions were 51.74, 46.89, and 34.37 kJ/mol, respectively, indicating that reduction proceeds more easily for them. The ln-ln and Sharp analysis implied that the C 2 F reduction was described by the Avrami-Erofeev function, thus appeared as a 2D reaction during the whole reaction, whereas the CF and CF 2 reductions were expressed initially by a 2D reaction when α < 0.5 and subsequently by a 3D reaction when α > 0.5. In the new proposed reduction model, the Fe 2 O 3 content increases in the CaO-Fe 2 O 3 system from C 2 F to CF 2 and the gradual promotion of the reduction rate leads to the reduction process of the C 2 F, CF, and CF 2 samples occurring by a 2D tending to 3D reaction mechanism.

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“…In a detailed study the rate of solidification of the sulfide melt should be taken into account (21). Mazanek et al (22) carried out the measurement of magnetization with a magnetic balance to estimate the sintering properties. Equation (7) is also valid for an estimation of the amount of SO, gas liberated from the melt under reduced pressures.…”

Section: Emf and Magnetite Measurements In Connection With The Vacuummentioning

confidence: 99%