Morphological Investigation of Calcium Carbonate during Ammonification-Carbonization Process of Low Concentration Calcium Solution

Cheng, Hao; Zhang, Xiaoxi; Song, Huiping

doi:10.1155/2014/503696

Cited by 27 publications

(15 citation statements)

References 21 publications

(19 reference statements)

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“…The SEM images given in Fig. 3 showed that calcium carbonate particles obtained by the conversion of calcium-containing solids generally had a rhombohedral morphology, as also observed for the calcium carbonate precipitates of calcite polymorph in different literature studies (Kralj et al, 2004;Cheng et al, 2014;Liu et al, 2014), but the particles obtained from Ca(OH)2 were more rounded, agglomerated and smaller than the particles obtained from CaSO4•2H2O.…”

Section: Resultssupporting

confidence: 70%

Direct conversion of alkaline earth metal hydroxides and sulfates to carbonates in ammonia solutions

Ehsani¹,

Ehsani²,

Üçyıldız³

et al. 2021

Physicochem. Probl. Miner. Process.

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In this study, the direct conversion behaviors of different alkaline earth metal solids (the hydroxides and the sulfates of alkaline earth metals Ca, Sr, Ba and Mg) to their corresponding carbonates in dissolved carbonate-containing pregnant solutions obtained by direct leaching of a smithsonite (ZnCO3) ore sample in aqueous ammonia solutions having different concentrations (4 M, 8 M and 13.3 M NH3) were investigated by using X-ray diffraction analyses at alkaline earth metal to dissolved carbonate mole ratios of 1:1 and 1:2, for revealing the conversion possibilities of dissolved carbonate in the pregnant solutions to solid carbonate by-products. The results of direct conversion experiments showed that Ca(OH)2, CaSO4•2H2O, Sr(OH)2•8H2O and Ba(OH)2•8H2O converted to their corresponding carbonates, SrSO4 partially converted to SrCO3 as observed by the presence of unreacted SrSO4 peaks in X-ray diffraction patterns of the converted solids, and BaSO4 did not convert to BaCO3 because of its lower solubility with respect to BaCO3. On the other hand, it was observed that Mg(OH)2 did not convert to MgCO3, but MgSO4•7H2O converted dominantly to an uncommon phase, which was tentatively identified as Mg5Zn3(CO3)2(OH)12•H2O. In the study, a complete discussion on the conversion behaviors of alkaline earth metal solids to their corresponding carbonates was given considering the differences between their solubility product constants and the changes in the free energies of the theoretical conversion reactions. In addition, infrared spectra and scanning electron microscope images of some of the converted solids were also presented for characterization purposes.

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Section: Resultssupporting

confidence: 70%

Direct conversion of alkaline earth metal hydroxides and sulfates to carbonates in ammonia solutions

Ehsani¹,

Ehsani²,

Üçyıldız³

et al. 2021

Physicochem. Probl. Miner. Process.

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“…(a) Distribution of CO 2 uptake among crystalline and amorphous calcium- and magnesium-carbonates for the different types of slags: EAF, BOF, ac-BF, SS, and LS. (b) Micrograph of the carbonated SS slag showing prismatic crystals characteristic of calcium carbonate produced from solutions containing impurities. , (c) XRD patterns for the non-carbonated (blue) and carbonated (red) SS slag. The phases are marked as follows: 0melilite ((Ca,Na) 2 SiO 7 ), 1monticellite (CaMgSiO 4 ), 2perovskite (CaTiO 3 ), 3enstatite (MgSiO 3 ), 4strontiowhitlockite (Sr 9 Mg(PO 4 ) 6 (PO 3 OH)), 5carboborite (Ca 2 Mg(CO 3 ) 2 B 2 (OH) 8 ·4(H 2 O)), 6ilmenite (FeTiO 3 ), 7bernalite (Fe(OH) 3 ), 8brucite (Mg(OH) 2 ), and 9mayenite (Ca 12 Al 14 O 33 ).…”

Section: Resultsmentioning

confidence: 99%

Controls on CO₂ Mineralization Using Natural and Industrial Alkaline Solids under Ambient Conditions

Plante

Mehdipour

Shortt

et al. 2021

ACS Sustainable Chem. Eng.

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The extent to which carbon dioxide (CO 2 ) mineralization ("carbonation") using alkaline solids can reduce atmospheric CO 2 concentrations is dictated by the rate of divalent alkaline metal release from such solids. These solids have distinct reactivities, that is, bulk dissolution rates, which dictate their rates of carbonation. To assess the feasibility of utilizing alkaline solids to mitigate CO 2 emissions at scale, assessments of practical carbonation potentials under ambient conditions, which are often distinct from their stoichiometric carbonation potential as described by their bulk chemical composition, are needed. Therefore, the carbonation (or "CO 2 mineralization") potentials of 16 naturally occurring (mafic and ultramafic) rocks and industrial alkaline solids (fly ashes and slags) were quantified. In general, the extent of carbonation for the pulverized and as-received solids which is achievable under ambient conditions [25 °C, 1 bar]in the presence of excess CO 2 and waterthat is, the carbonation potential, is correlated with the CaO and MgO content and varies inversely with the SiO 2 content. Particularly, the carbonation efficiency (i.e., the ratio of the measured to the stoichiometric carbonation potential) is controlled by the atomic topology (network connectivity) of the solid reactant suggesting that network rupture is the rate-controlling step of dissolution and, hence, carbonation. Based on our data, we offer estimates of CO 2 removal that can be achieved under ambient exposure conditions to assess the controls and capacity of ambient CO 2 mineralization as a carbon dioxide removal strategy.

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“…In the literature [ 4 , 24 ], following the reaction between CaCl 2 + Na 2 CO 3 at different temperatures, the calcite form was obtained at 25 °C.…”

Section: Resultsmentioning

confidence: 99%

Calcium Carbonate–Carboxymethyl Chitosan Hybrid Materials

Fortună¹,

Ungureanu

Jitareanu

2021

Materials

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In the present work, precipitated calcium carbonate (PCC) and carboxymethyl chitosan (CMC) were prepared to obtain new hybrid materials used in papermaking. In the first step, occurred the precipitation of CaCO3 in solution containing CMC at different levels (0.5%, 1%, and 1.5%). In the second step, PCC–CMC hybrid material (25%) was added to pulp suspension, and the sheets were made. The effect of PCC–CMC on paper properties (mechanical and optical) was systematically investigated. Breaking length, the brightness and opacity of the sheets obtained with the PCC–CMC material were better than the sheets fabricated with the unmodified PCC at similar levels of content.

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Morphological Investigation of Calcium Carbonate during Ammonification-Carbonization Process of Low Concentration Calcium Solution

Cited by 27 publications

References 21 publications

Direct conversion of alkaline earth metal hydroxides and sulfates to carbonates in ammonia solutions

Direct conversion of alkaline earth metal hydroxides and sulfates to carbonates in ammonia solutions

Controls on CO₂ Mineralization Using Natural and Industrial Alkaline Solids under Ambient Conditions

Calcium Carbonate–Carboxymethyl Chitosan Hybrid Materials

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Morphological Investigation of Calcium Carbonate during Ammonification-Carbonization Process of Low Concentration Calcium Solution

Cited by 27 publications

References 21 publications

Direct conversion of alkaline earth metal hydroxides and sulfates to carbonates in ammonia solutions

Direct conversion of alkaline earth metal hydroxides and sulfates to carbonates in ammonia solutions

Controls on CO2 Mineralization Using Natural and Industrial Alkaline Solids under Ambient Conditions

Calcium Carbonate–Carboxymethyl Chitosan Hybrid Materials

Contact Info

Product

Resources

About

Controls on CO₂ Mineralization Using Natural and Industrial Alkaline Solids under Ambient Conditions