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Updated: Jul 13, 2025
11:14
Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
12.4K
Dissolution Behavior of Lime with Different Properties into Converter Slag
Mengxu Zhang1, Jianli Li1,2, Cao Jia1
1The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China.
Materials (Basel, Switzerland)
|October 14, 2023
Summary
Steel slag utilization is hindered by free calcium oxide (f-CaO). This study examines lime-slag interactions, revealing a 2CaO·SiO2 layer forms, impacting dissolution rates and mass transfer during steelmaking.
Area of Science:
- Materials Science
- Chemical Engineering
- Metallurgical Engineering
Background:
- China's vast crude steel production generates substantial steel slag, posing utilization challenges due to free calcium oxide (f-CaO) content.
- The presence of f-CaO in steel slag leads to volume instability, limiting its comprehensive application.
- Understanding lime-slag interactions is crucial for mitigating these issues and improving steel slag utilization.
Purpose of the Study:
- To investigate the dynamic transformation of the lime-slag interface during converter smelting.
- To analyze the dissolution rate of lime in steel slag under varying conditions.
- To elucidate the formation and impact of key mineral phases on mass transfer.
Main Methods:
- Utilized an Electron Probe Micro Analyzer (EPMA) with an energy-dispersive spectrometer for detailed interface analysis.
- Simulated converter smelting conditions at 1400 °C.
- Investigated the effect of lime particle size and calcination rate on dissolution behavior in different slag compositions (A1-A4).
Main Results:
- Observed significant interface transformations, including the formation of CaO-FeO solid solution, (Ca, Mg, Fe) olivine, and low-melting point silicates at 1400 °C.
- A robust 2CaO·SiO2 layer formed as FeO content decreased, generated from CaO and (Ca, Mg, Fe) olivine interactions.
- The thickest 2CaO·SiO2 layer formed on 20 mm lime (0% calcination) after 120s in slag A2; dissolution rates increased with lime particle size but showed complex behavior with calcination rates.
Conclusions:
- The formation of a continuous, high-melting point 2CaO·SiO2 layer significantly hinders mass transfer between lime and slag.
- Understanding these interfacial reactions is key to controlling steel slag properties and enhancing its utilization.
- The study provides critical insights into the mechanisms governing lime dissolution in steel slag, relevant for process optimization.
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