Investigation of Effects of SiO2 Content and Cooling Rate on Crystallization in Fe2O3-CaO-SiO2 System Using In Situ Confocal Laser Scanning Microscopy

Park, Tae Jun; Choi, Joon Sung; Min, Dong Joon

doi:10.1007/s11663-019-01518-y

Cited by 7 publications

(5 citation statements)

References 19 publications

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“…Finally, industrial typical pollutants, PG and desilication PG are chosen as the research objects to investigate their reaction characteristics under the optimized conditions (1100 °C, C/Ca = 1.75, CO 2 concentration 7.5%). Previous studies have shown that cooling rate has a significant impact on the activity of CaO 30 . Therefore, this study compared the effects of rapid cooling of phosphogypsum (PRC), slow cooling of phosphogypsum (PSC), and desilication phosphogypsum with rapid cooling (DPRC) on the yield of CaO.…”

Section: Resultsmentioning

confidence: 99%

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Experimental study on preparation of calcium oxide by coal reduction of calcium sulfate in carbon dioxide atmosphere

Wang

2023

J of Chemical Tech & Biotech

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BACKGROUND: Recent studies show that CaO is being produced from CaSO 4 by CO reduction using fixed-bed reactors. However, the product yield is low and the reaction time is long. Furthermore, the high cost of CO hinders its application in industrial processes. Therefore, a new process is proposed for preparing CaO by CaSO 4 decomposition using lignite under CO 2 . The influence of various process conditions on the production of CaO by CaSO 4 decomposition is investigated by combining kinetic and FactSage simulations. Finally, a typical industrial gypsumphosphogypsum (PG)is used for experimental verification.RESULTS: The study found that adding CO 2 during the coal reduction of CaSO 4 increases the CaO yield. The ideal conditions are 1.75 C/Ca molar ratio, 7.5% CO 2 concentration at 1100 °C with the maximum CaSO 4 decomposition rate and CaO yield of 99.63% and 99.28%, respectively. CaO generation is carried out using a two-step process. Initially, CaSO 4 is reduced to become CaS and CaO, and CaS interacts with CaSO 4 to produce CaO. Secondly, the reaction between CaS and CO 2 produces CaO. The nucleation and growth model with g(⊍) = −ln(1 − ⊍) is applicable to both processes. The experimental use of PG confirms the above conclusions, but SiO 2 in PG reacts with CaO to produce Ca 2 SiO 4 and affect the CaO yield.CONCLUSION: The addition of CO 2 promotes the conversion process of CaSO 4 to CaO. Increasing the temperature, C/Ca molar ratio and CO 2 concentration favor the decomposition of CaSO 4 into CaO. This study offers advice for using CaSO 4 products like PG as resources.

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Section: Resultsmentioning

confidence: 99%

“…Previous studies have shown that cooling rate has a significant impact on the activity of CaO. 30 Therefore, this study compared the effects of rapid cooling of phosphogypsum (PRC), slow cooling of phosphogypsum (PSC), and desilication phosphogypsum with rapid cooling (DPRC) on the yield of CaO. The findings are displayed in Fig.…”

Section: Dynamical Analysismentioning

confidence: 99%

Experimental study on preparation of calcium oxide by coal reduction of calcium sulfate in carbon dioxide atmosphere

Wang

2023

J of Chemical Tech & Biotech

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“…The mixed powders of each composition were homogenized by pre-melting in a muffle furnace at 1773 K for 12 h in a N 2 atmosphere. Previous studies suggest that the equilibrium state of the molten slag can be achieved by using a holding time of more than 2 h [26][27][28]. Therefore, having being subjected to holding times of 12 h at 1773 K, the premelted slags used in this study were at equilibrium.…”

Section: Methodsmentioning

confidence: 99%

Influence of Al2O3 Content and Cooling Rate on Crystallization in Fe2O3–CaO–SiO2–Al2O3 Systems

2021

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The behavior of silico-ferrite of calcium and aluminum (SFCA) phases and the influence of sintered ore quality were investigated using a confocal laser scanning microscope to understand how the Al 2 O 3 content of iron ore affects the sintered ore structure and the crystallization behavior of SFCA in a Fe 2 O 3 -CaO-Al 2 O 3 -SiO 2 pseudo-quaternary system. The experimental results were used to inform simulations of the heterogeneous dynamic behavior in response to the rapid temperature changes and various chemical compositions typically encountered in actual sintering processes. Increasing the Al 2 O 3 content in the Fe 2 O 3 -CaO-Al 2 O 3 -SiO 2 pseudo-quaternary system led to the hematite content decreasing, which affects the reducibility of the sintered ore. The correlation between the creation of SFCA and the cooling effect associated with varying the Al 2 O 3 is discussed in detail.

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“…[ 1–3 ] The typical properties of sintered ore mainly include the reducibility, mechanical strength, and reduction degradation, which are influenced most by its composition and structure of the bonding phases during heating and cooling in the sinter process. [ 4–10 ] Thus, improving the sintered ore quality should be fundamentally based on understanding the properties of raw materials, especially in terms of the mineralogical characteristics of iron ores. [ 11,12 ]…”

Section: Introductionmentioning

confidence: 99%

Effect of Bonding Area Formation During Sintering on the Reaction Characteristics of Iron Ores

Park

Kim

Sohn

2021

steel research int.

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This study aims to understand the effect of sintering at 1623 K on the reaction characteristics of iron ores. By investigating the reaction characteristics of nine different iron ores with disparate properties, new reactivity indices including the iron ore reactivity index (IRI) and iron ore blending reactivity index (IBRI) independent of the sample size are derived based on the melt penetration depth of preformed cubicalironore tablets. Furthermore, the effect of sintering on the reactivity of iron ore is also identified. Using a rapid heating/cooling infrared furnace equipment, duplicate iron ore reaction tests are conducted to increase the reproducibility of the results. The case of a high IBRI in the sintering process increases the product yield and average particle size of the sinter. When the IBRI increases by 0.1, the product yield increases by 0.4% and the average size of the sintered ore increases by 0.1 mm. The results show that the degree of reaction between iron ore and additives can be estimated during the iron ore blending step and be easily applied in managing commercial‐scale sinter production and quality.

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Investigation of Effects of SiO2 Content and Cooling Rate on Crystallization in Fe2O3-CaO-SiO2 System Using In Situ Confocal Laser Scanning Microscopy

Cited by 7 publications

References 19 publications

Experimental study on preparation of calcium oxide by coal reduction of calcium sulfate in carbon dioxide atmosphere

Experimental study on preparation of calcium oxide by coal reduction of calcium sulfate in carbon dioxide atmosphere

Influence of Al2O3 Content and Cooling Rate on Crystallization in Fe2O3–CaO–SiO2–Al2O3 Systems

Effect of Bonding Area Formation During Sintering on the Reaction Characteristics of Iron Ores

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