Dissolution behavior of partially calcined limestone with residual CO2 in converter slag

Tian, Yinbao; Liu, Yu; Li, Guangqiang; Li, Yongqian; Zhang, Zhan; Tan, Chuan Seng

doi:10.1016/j.jmrt.2022.01.163

Cited by 4 publications

(2 citation statements)

References 28 publications

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“…The schematic representation in Figure 14 elucidates the dissolution process of quicklime in a CaO-FeO-SiO 2 -MgO-based slag system at 1350 • C. Upon introducing rapidly calcined quicklime into the slag, the liquid slag envelops the lime particles. It infiltrates the interior of the lime through cracks and micropores formed during calcination, initiating the lime-slag interface reaction [9][10][11]. Due to the swift diffusion rate of FeO within the slag, it reacts with CaO to give rise to a CaO-FeO solid solution.…”

Section: Evolution Of the Reaction Interface Between Lime And Slag Du...mentioning

confidence: 99%

Dissolution Behavior of Lime with Different Properties into Converter Slag

Zhang,

Li,

Jia

et al. 2023

Materials

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China’s 2022 crude steel production soared to an impressive 1.018 billion tons, and steel slag constituted approximately 10% to 15% of this massive output. However, a notable hindrance to the comprehensive utilization of steel slag arises from the fact that it contains 10% to 20% of free calcium oxide (f-CaO), resulting in volume instability. To address this challenge, our study delved into the dynamic transformation of the interface between lime and slag, as well as the fluctuations in the dissolution rate of lime. An Electron Probe Micro Analyzer, equipped with an energy-dispersive spectrometer, was employed for the analysis. Our findings revealed that the configuration of the reaction interface between quicklime and slag underwent alterations throughout various phases of converter smelting. At a temperature of 1400 °C, several significant transformations occurred, including the formation of a CaO-FeO solid solution, (Ca, Mg, Fe) olivine, and low-melting point (Ca, Mg) silicate minerals. With the gradual reduction in FeO content, a robust and high-melting 2CaO·SiO2 layer emerged, generated through the interaction between CaO and (Ca, Mg, Fe) olivine. Furthermore, for lime with a particle size of 20 mm and a calcination rate of 0%, the thickest layer of 2CaO·SiO2 was observed after 120 s of dissolution in slag A2 at 1400 °C. Overall, the dissolution rates of lime with different particle sizes in slag A1 to A4 showed a gradual increase. On the other hand, the dissolution rates of lime with different calcination rates in slag A1 to A4 exhibited an initial increase, followed by a decrease, and then another increase. The formation of a high-melting point and continuous dense 2CaO·SiO2 layer during the dissolution process hindered the mass transfer between lime and slag.

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Section: Evolution Of the Reaction Interface Between Lime And Slag Du...mentioning

confidence: 99%

Dissolution Behavior of Lime with Different Properties into Converter Slag

Zhang,

Li,

Jia

et al. 2023

Materials

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“…When the calcined quicklime is added to the slag, the slag gradually enters the interior of the lime through the cracks and micropores generated during calcination. [9][10][11] At this point, an interface reaction occurs between the slag and the lime at the contact surface. Due to its fast diffusion rate, FeO in the slag diffuses into the interior of the lime and reacts with CaO to form a CaO-FeO solid solution.…”

Section: Analysis Of the Mechanism Of Lime Dissolution In Slagmentioning

confidence: 99%

Evolution of Interface Characteristic between Quicklime and CaO–SiO₂–Fe_tO–MgO Melt during Slag‐Forming Procedure in Converter under Different Times

Zhang

Jia

et al. 2023

steel research int.

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In 2022, China produced 1.018 billion tons of crude steel, with steel slag accounting for 10–15% of the output. The presence of 10–20% f‐CaO in steel slag causes volume instability, hindering comprehensive utilization. The generation of f‐CaO is closely associated with the dissolution of quicklime during the converter slag‐forming procedure. This study focuses on investigating the evolution of the lime–slag interface and the variations in lime dissolution rate under different slag conditions using the electron probe microanalyzer and ImageJ. The results reveal that the formation of the CaO–FeO solid solution, (Ca, Mg, Fe) olivine, and low‐melting point (Ca, Mg) olivine at 1400 °C. As the FeO content decreases, a dense and high‐melting‐point 2CaO·SiO2 layer is formed. A maximum thickness of the 2CaO·SiO2 layer is precipitated at a dissolution time of 180 s. Additionally, the average dissolution rate of lime in different slags shows an initial increase followed by a subsequent decrease. Among the slag studied, the highest average dissolution rate is in slag A3 at 2.24 × 10−6 m s−1, while the lowest rate is in slag A4 at 1.49 × 10−6 m s−1. The presence of the 2CaO·SiO2 layer hinders the mass transfer, thereby further inhibiting the reaction.

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A Strategy for Partial Replacement of Lime by Limestone and Its Impact on Basic Oxygen Furnace Steelmaking

Gupta,

Sarkar,

Roy

2024

steel research int.

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Production of steel in a sustainable manner is gaining importance day by day. Optimizing fluxes in basic oxygen furnace (BOF) steelmaking, such as partial replacement of lime with limestone, can be a step toward this. The heat available in BOF can decompose the limestone which partially avoids the need for calcination in lime kiln. However, the size, quantity, and time of limestone addition in BOF are important parameters as they influence the decomposition behavior of limestone. The associated problems of slopping, presence of uncalcined limestone, fines generation, etc. are also influenced by these parameters. In the present study, laboratory experiments are conducted by changing the size, temperature, and time of exposure which help in understanding high‐temperature behavior of limestone. With these inputs, along with theoretical calculations, a trial is conducted in a 160 t BOF by limestone addition and replacing equivalent amount of lime. The study focusses on the benefits of limestone addition in BOF along with other aspects, that is, impact on blow profiles, slag condition, lining wear, etc. Characterization of slags help in explaining the improvement observed during this trial. The article presents the findings of laboratory studies and limestone addition trials and uniquely highlights its overall impact on BOF steelmaking.

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Dissolution behavior of partially calcined limestone with residual CO2 in converter slag

Cited by 4 publications

References 28 publications

Dissolution Behavior of Lime with Different Properties into Converter Slag

Dissolution Behavior of Lime with Different Properties into Converter Slag

Evolution of Interface Characteristic between Quicklime and CaO–SiO₂–Fe_tO–MgO Melt during Slag‐Forming Procedure in Converter under Different Times

A Strategy for Partial Replacement of Lime by Limestone and Its Impact on Basic Oxygen Furnace Steelmaking

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Dissolution behavior of partially calcined limestone with residual CO2 in converter slag

Cited by 4 publications

References 28 publications

Dissolution Behavior of Lime with Different Properties into Converter Slag

Dissolution Behavior of Lime with Different Properties into Converter Slag

Evolution of Interface Characteristic between Quicklime and CaO–SiO2–FetO–MgO Melt during Slag‐Forming Procedure in Converter under Different Times

A Strategy for Partial Replacement of Lime by Limestone and Its Impact on Basic Oxygen Furnace Steelmaking

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Evolution of Interface Characteristic between Quicklime and CaO–SiO₂–Fe_tO–MgO Melt during Slag‐Forming Procedure in Converter under Different Times