Synthesis of Ca(OH)2 and Na2CO3 through anion exchange between CaCO3 and NaOH: effect of reaction temperature

Simoni, Marco; Hanein, Theodore; Woo, Chun Long; Nyberg, Magnus; Tyrer, Mark; Provis, John L.; Kinoshita, Hajime

doi:10.1039/d2ra05827h

Cited by 7 publications

(4 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In those studies, alkaline solutions such as NaOH and KOH tended to have higher concentrations. 9–12 Kojima et al concluded that a suitable amount of alkaline reagent for obtaining Ca(OH) 2 from gypsum was a OH/Ca ratio greater than 2.6. 12 In the present study, we focused on recovering unused alkaline wastewater at lower concentrations and on establishing the optimal pH for obtaining Ca(OH) 2 from gypsum.…”

Section: Resultsmentioning

confidence: 99%

“…This technique does not generate CO 2 gas, yielding sodium carbonate as a useful chemical instead. [9][10][11] Another approach for obtaining Ca(OH) 2 is the treatment of gypsum with aqueous NaOH or potassium hydroxide (KOH). [12][13][14] These techniques exploit the different solubilities of CaCO 3 , gypsum, and Ca(OH) 2 and proceed in accordance with reactions (2)-( 4):…”

Section: Introductionmentioning

confidence: 99%

“…This technique does not generate CO 2 gas, yielding sodium carbonate as a useful chemical instead. 9–11 Another approach for obtaining Ca(OH) 2 is the treatment of gypsum with aqueous NaOH or potassium hydroxide (KOH). 12–14 These techniques exploit the different solubilities of CaCO 3 , gypsum, and Ca(OH) 2 and proceed in accordance with reactions (2)–(4):CaCO 3 + 2NaOH → Na 2 CO 3 + Ca(OH) 2 CaSO 4 ·2H 2 O + 2NaOH → Na 2 SO 4 + Ca(OH) 2 + 2H 2 OCaSO 4 ·2H 2 O + 2KOH → K 2 SO 4 + Ca(OH) 2 + 2H 2 OHowever, these methods require a high concentration of NaOH.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Environmentally responsible production of lime from recycled gypsum and weakly alkaline wastewater

Tafu,

Suzuki,

Nakamura

et al. 2024

New J. Chem.

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Environmentally responsible production of lime from recycled gypsum and weakly alkaline wastewater

Tafu,

Suzuki,

Nakamura

et al. 2024

New J. Chem.

View full text Add to dashboard Cite

show abstract

“…This reaction is an example of a double displacement reaction, also known as a metathesis reaction. In this type of reaction, the cations and anions switch between two reactants to form new products (Simoni et al 2022).…”

Section: Effect Of Alkaline Pretreatmentmentioning

confidence: 99%

Robust pretreatment in combination with ultrasound-assisted surfactant to improve the enzymatic hydrolysis of Eucalyptus pellita

Zhand,

Yang,

Kang

et al. 2024

BioRes

View full text Add to dashboard Cite

Alkaline pretreatment stands out as a valuable strategy in biomass conversion to overcome the recalcitrance of biomass by removing lignin and a part of hemicellulose. This enhances enzyme accessibility and promotes saccharification. However, increasing the alkaline concentration to enhance the delignification and improve glucose yield together presents inherent limitations. In this experiment the amount of delignification and glucose yield resulting from surfactant associated with sonication during mild alkaline pretreatment of Eucalyptus pellita was investigated. Also, the effect of various factors (sonication temperature and surfactant immersion time) on delignification and glucose yield were examined. The results demonstrated that surfactant associated with sonication pretreatment could overcome the limitation of alkaline pretreatment and could increase the amount of delignification alongside enzymatic hydrolysis glucose yield of Eucalyptus pellita wood by around 90%. The findings indicated that surfactant-assisted with sonication during mild alkaline pretreatment of Eucalyptus pellita (i.e., hardwood) could be recommended as a supporting pretreatment method for the production of monomeric sugars.

show abstract

Comparison of thermogravimetry response of alkali-activated slag and Portland cement pastes after stopping their hydration using solvent exchange method

Bílek,

Švec,

Másilko

et al. 2024

J Therm Anal Calorim

View full text Add to dashboard Cite

The critical step for any subsequent instrumental analysis of cementitious binders is to stop their hydration reactions, i.e., to remove free water. One of the most available techniques is a solvent exchange method. However, the solvents are known to be strongly bound in ordinary Portland cement (OPC) paste and alter the results of thermogravimetric analysis (TGA) and sensitive hydrates, while their effect on TGA response of alkali-activated slag (AAS) has not been comprehensively investigated. Therefore, the objective of this paper is to track the effects of fundamental aspects of the solvent exchange on the TGA response of AAS with different sodium activators (hydroxide, carbonate, waterglass) and to support these results by X-ray diffraction and effluent gas analysis. All solvents used (acetone, diethyl ether, isopropyl alcohol, ethanol, and methanol) affected the TGA response of all tested pastes, and their effect was enhanced by prolonged immersion time. All solvents induced an additional mass loss at around 800 °C and, especially for OPC paste, increased in situ carbonation, even in an inert atmosphere. Methanol and ethanol had a detrimental effect on ettringite and decreased the basal distance of the C–(A)–S–H gel, while they only marginally affected gaylussite. For AAS, hydration stoppage by washing out the alkali-rich pore solution with water was also investigated and can usually be recommended (except for its detrimental effect on gaylussite), as it is more efficient than organic solvents, which lack solubility for activators. Methanol and ethanol are the most suitable alternatives, particularly for NaOH.

show abstract

Synthesis of Ca(OH)₂ and Na₂CO₃ through anion exchange between CaCO₃ and NaOH: effect of reaction temperature

Abstract: The chemical decarbonisation of CaCO3 was successfully tested in a range of mild temperatures simulating those oscillations occurring within processes, and the kinetic parameters were gained.

Cited by 7 publications

References 45 publications

Environmentally responsible production of lime from recycled gypsum and weakly alkaline wastewater

Environmentally responsible production of lime from recycled gypsum and weakly alkaline wastewater

Robust pretreatment in combination with ultrasound-assisted surfactant to improve the enzymatic hydrolysis of Eucalyptus pellita

Comparison of thermogravimetry response of alkali-activated slag and Portland cement pastes after stopping their hydration using solvent exchange method

Contact Info

Product

Resources

About