Purification of slag-derived leachate and selective carbonation for high-quality precipitated calcium carbonate synthesis

Crom, Koen De; Chiang, Yi Wai; Gerven, Tom Van

doi:10.1016/j.cherd.2015.07.029

Cited by 27 publications

(25 citation statements)

References 16 publications

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“…Si can retain metal ions, such as Fe, during its hydration (by forming silica gel), indicating that silica gel affects leaching selectivity. Preventing silica-gel formation by adjusting L/S adversely affects the purity of carbonate minerals, which is in agreement with the results reported by Crom et al [30]. Impurities retained in the silica gel phase, such as Fe, Mn, and Al, were removed by washing with deionized water, affording a high-purity (~99%) amorphous silica powder with a wide specific surface area (several hundred meter square per gram).…”

Section: Discussionsupporting

confidence: 80%

“…Huijgen et al [13] have reported that wollastonite (CaSiO 3 ) can be used as a metal Figure 1, JEOL-7800F, Jeol, Tokyo, Japan) used herein was obtained from a steel making company in South Korea; slag was milled, and powders with a mesh size of below 200 were collected. As reported in previous studies utilizing BFS [2,30], crystal phases of BFS were not observed by XRD analysis (Analytical X-ray B.V.X'pert-MPD, Philips, EA Almelo, The Netherlands; scanning range of 3 • -70 • (2θ) (CuKα) using a step size of 0.02 • (2θ) at 40 kV/40 mA). The concentrations of elements in oxide compounds were quantitatively measured by X-ray fluorescence (XRF; MXF-2400, Shimadzu, Kyoto, Japan, approximately 1 g of a sample was used to make a glass disc with 5.5 g of Li 2 B 4 O 7 as the flux) for the estimation of the leaching ratio (LCH.…”

Section: Introductionmentioning

confidence: 75%

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Leaching of Metal Ions from Blast Furnace Slag by Using Aqua Regia for CO2 Mineralization

et al. 2016

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Blast furnace slag (BFS) was selected as the source of Ca for CO 2 mineralization purposes to store CO 2 as CaCO 3 . BFS was dissolved using aqua regia (AR) for leaching metal ions for CO 2 mineralization and rejecting metal ions that were not useful to obtain pure CaCO 3 (as confirmed by XRD analysis). The AR concentration, as well as the weight of BFS in an AR solution, was varied. Increasing the AR concentration resulted in increased metal ion leaching efficiencies. An optimum concentration of 20% AR was required for completely leaching Ca and Mg for a chemical reaction with CO 2 and for suppressing the leaching of impurities for the production of high-purity carbonate minerals. Increasing the liquid-to-solid ratio (L/S) resulted in the increased leaching of all metal ions. An optimum L/S of 0.3/0.03 (=10) was required for completely leaching alkaline-earth metal ions for CO 2 mineralization and for retaining other metal ions in the filtered residue. Moreover, the filtrate obtained using 20% AR and an L/S of 0.3/0.03 was utilized as Ca sources for forming carbonate minerals by CO 2 mineralization, affording CaCO 3 . The results obtained herein demonstrated the feasibility of the use of AR, as well as increasing pH, for the storage of CO 2 as high-purity CaCO 3 .

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Section: Discussionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 75%

Leaching of Metal Ions from Blast Furnace Slag by Using Aqua Regia for CO2 Mineralization

et al. 2016

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“…The results of previous studies of the dissolution of slag using acetic acid [6,8,9] can be summarized as follows:…”

Section: Optimization Of Leaching Parametersmentioning

confidence: 99%

Effects of Experimental Parameters on the Extraction of Silica and Carbonation of Blast Furnace Slag at Atmospheric Pressure in Low-Concentration Acetic Acid

Song

Park

Kim

et al. 2017

Metals

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Blast furnace slag (BFS), a calcium-rich industrial byproduct, has been utilized since 2005 as a mineral carbonation feedstock for CO 2 sequestration, producing calcium carbonate precipitates. In this study, the conditions for the dissolution of Ca and Si in acetic acid, and subsequent carbonation, were elaborated. For this purpose, the retardation of the polymerization of silicon was attempted by varying the concentration of acetic acid, temperature, and leaching time. An inductively coupled plasma (ICP) analysis revealed that both the Ca and Si dissolved completely within 30 min in 5% acetic acid at room temperature. This high dissolution value can be attributed to the fact that Ca was bound to O rather than to Si, as determined by X-ray photoelectron spectroscopy (XPS). The use of CO 2 -absorbed monoethanolamine enabled the complete carbonation of BFS at ambient conditions without the need for a pH swing. The presence of dissolved silica was found to affect the polymorphs of the precipitated CaCO 3 . We believe that this process offers a simple method for manipulating the composites of products obtained by mineral carbonation diminishing the leaching residues.

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“…Ever since acetic acid (a weak acid with a pKa = 4.7) was shown to be effective for the extraction of Ca from natural calcium silicates in mineral carbonation reactions [4], it has been used as a mild extraction agent for the selective extracting of Ca from BFS [5][6][7][8][9][10]. Most studies regarding the mineral carbonation of BFS are dedicated to the production of relatively pure CaCO 3 following selective Ca dissolution.…”

Section: Introductionmentioning

confidence: 99%

“…Most studies regarding the mineral carbonation of BFS are dedicated to the production of relatively pure CaCO 3 following selective Ca dissolution. On the other hand, the other major element present in BFS, namely Si, is considered to be a target material to be extracted as silica gel, along with other impurities during acid dissolution processes [5,8,10]. Temperatures above 50 • C are recommended for the extraction of Ca and the removal of Si during the dissolution process [9].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Silica-Alumina Nanoparticles via Blast-Furnace Slag Dissolution in Low-Concentration Acetic Acid for Carbonation

et al. 2017

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Blast-furnace slag (BFS) has been used as a feedstock for CO 2 sequestration by indirect mineral carbonation to produce calcium carbonate precipitates and solid residues. The most-abundant elements in these residues, Si and Al, are usually considered to be impurities that need to be removed in acid-dissolution processes involving BFS. The co-production of value-added materials from these residues is an attractive option for strengthening the economic competitiveness of mineral carbonation methods. In view of this, we separated the Si and Al, as their hydrated forms, during the dissolution of BFS in acetic acid prior to carbonation. During the sol-gel processing of Si-Al nanoparticles, a catalyst is usually required during the hydrolysis and subsequent condensation processes. In this study, only condensation occurs because the low-concentrations of acetic acid used facilitate in-situ hydrolysis during the dissolution process. Aging was carried out not only to structurally arrange the Si and Al but also to oxidize the marginal Fe(II) to reddish Fe(III). Silica-alumina nanoparticles (78% Si and 22% Al) were prepared by a simple sol-gel route at ambient pressure. These nanoparticles were amorphous and below 20 nm in size. Fourier-transform infrared (FT-IR) studies reveal that the nanoparticles consist of Si-O-Si and Si-O-Al bonds. 27 Al nuclear magnetic resonance (NMR) spectroscopy reveals a significant resonance corresponding to tetra-coordinated Al inside the particle framework.

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Purification of slag-derived leachate and selective carbonation for high-quality precipitated calcium carbonate synthesis

Cited by 27 publications

References 16 publications

Leaching of Metal Ions from Blast Furnace Slag by Using Aqua Regia for CO2 Mineralization

Leaching of Metal Ions from Blast Furnace Slag by Using Aqua Regia for CO2 Mineralization

Effects of Experimental Parameters on the Extraction of Silica and Carbonation of Blast Furnace Slag at Atmospheric Pressure in Low-Concentration Acetic Acid

Preparation of Silica-Alumina Nanoparticles via Blast-Furnace Slag Dissolution in Low-Concentration Acetic Acid for Carbonation

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