Issue 14, 2021, Issue in Progress

Effects of pH and metal composition on selective extraction of calcium from steel slag for Ca(OH)2 production

Abstract

This research article explains the effects of pH and metal composition on the selective calcium extraction from steel slag. The operating parameters including extraction solvent type, solvent concentration, metal composition of steel slag, substance type and pH were investigated. HCl, NH4Cl, NH4OH and NaOH were employed as solvents to extract Ca from steel slag. It has been shown that hydrochloric acid effectively extracts Ca. The high metal content in steel slag reacted sensitively to the solvent concentration, and a specific concentration was derived to selectively extract Ca. The optimal solvent for calcium extraction was 2 M HCl, which induced the extraction of 97% of Ca; 46% of Mg; 35% of Al; and 1% of Si from the steel slag. In order to separate Ca in the leaching solution from other metal ions, various acidic/basic substances were added to regulate the pH. The optimal pH level for removing the impurities without calcium was found to be 9.5. The precipitated impurities were removed by filtration, and the pH was adjusted to 13 or higher for Ca(OH)2(s) production. In conclusion, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) revealed that the Ca content produced through the process was more than 99%. It is expected that high-purity Precipitated Calcium Carbonate (PCC) will be achieved when the generated Ca(OH)2 is used as a source of calcium for mineral carbonation.

Graphical abstract: Effects of pH and metal composition on selective extraction of calcium from steel slag for Ca(OH)2 production

Article information

Article type
Paper
Submitted
06 Oct 2020
Accepted
04 Feb 2021
First published
22 Feb 2021
This article is Open Access
Creative Commons BY license

RSC Adv., 2021,11, 8306-8313

Effects of pH and metal composition on selective extraction of calcium from steel slag for Ca(OH)2 production

Y. H. Lee, H. Eom, S. M. Lee and S. S. Kim, RSC Adv., 2021, 11, 8306 DOI: 10.1039/D0RA08497B

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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