Effects of organic additives on calcium hydroxide crystallisation during lime slaking

Pesce, Cecilia Calvo; Pesce, Giovanni; Molinari, Marco; Richardson, Alan

doi:10.1016/j.cemconres.2020.106254

Cited by 28 publications

(11 citation statements)

References 79 publications

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“…While the PNCs pathway has changed our understanding of the classical view of nucleation, it is noteworthy that the dynamic behavior of the liquid-like intermediate phase is quite different, even in the same system. The stability of a liquid-like intermediate phase is often influenced by (in)organic additives and solvents. − …”

Section: Nonclassical Nucleation Modelsmentioning

confidence: 99%

Recent Advances in Nonclassical Crystallization: Fundamentals, Applications, and Challenges

Gao

Zhang

et al. 2021

Crystal Growth & Design

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Ubiquitous crystals play an important role in our daily lives. Recent studies on the properties and formation of crystals have proven the attachment of particles ranging from ion pairs to well-crystallized nanocrystals for crystallization. Compared with the monomer-by-monomer (i.e., atoms, ions, or molecules) addition described in long-standing classical theories, so-called nonclassical crystallization pathways are more complex due to the influence of nonspecific interactions influenced by the variation in system free energy and reaction kinetics. In view of the fact that detailed insights into nonclassical crystallization pathways have broadened the scope of research across various disciplines such as geological events, biomineralization mechanisms, environmental remediation, and the development of functional materials, this paper reviews the current state of the art in nonclassical nucleation (the prenucleation clusters pathway, aggregation pathway, etc.) and growth pathways (oriented attachment and random attachment) based on several highlights. In addition, the observed specific phenomena on crystallization in the last 10 years as well as recent advancements and achievements on the synthesis of mesocrystals are also elucidated. With implications and perspectives of nonclassical crystallization research proposed in this paper, this review aims to summarize research advancements regarding crystallizing systems. Emphasis will be placed on novel insights into nonclassical crystallization of materials, which are expected to provide completely new perspectives on the underlying crystallization mechanisms.

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Section: Nonclassical Nucleation Modelsmentioning

confidence: 99%

Recent Advances in Nonclassical Crystallization: Fundamentals, Applications, and Challenges

Gao

Zhang

et al. 2021

Crystal Growth & Design

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“…The modification of the properties of the material can be obtained by different mechanical or chemical processes, such as activation with organic or inorganic materials, mixing with other adsorbents/absorbents (e.g., activated carbon), and modification of the surface or pore structures [17]. It is also possible to significantly enlarge the specific surface of calcium hydroxide by adding a mixture of organic solvents and water to the CaO slaking water [18]. Other factors, including the concentration of HCl in the flue gas, and the air velocity, also affect the reaction between the sorbent and HCl in addition.…”

Section: Calcium Hydroxidementioning

confidence: 99%

Evaluation of Ca-Based Sorbents for Gaseous HCl Emissions Adsorption

et al. 2023

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The problem of acid gas exhaust emissions treatment has not been fully resolved at present. Dry adsorption of acid gases with alkaline sorbents is currently being investigated, to improve solid sorbents. In this study, 5 types of hydrated lime were characterised and tested. The sorption capacities were measured by means of a system consisting of a feed line (HCl/N2), a thermostatic reactor and a water absorber. The physical characteristics of sorbent samples were also compared. Analyses conducted with scanning electronic microscopy revealed that sample C1 showed uniform particle distribution. Samples C2 and C3 showed the co-presence of fine and coarse particles. Sample C4 showed very fine particles with agglomeration phenomena. In sample C5, fibrous elements were found. Energy dispersive spectrometry (EDS) analyses showed a similar composition of the samples, with the exception of the presence of Mg in some of them. After 30 min of testing, the following differences in sorption capacities with respect to C1 (3.59 mg g−1) were found: C2, −20%; C3, −13%; C4, −17%; C5, −3%. Higher sorption capacities were associated with more uniform particle size distributions. Conversely, agglomeration of fine particles may have adversely affected the performance of sorbents.

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“…The digestion of lime is typically a non-catalytic solid-liquid reaction, and therefore the conversion of calcium oxide to calcium hydroxide during digestion is influenced by numerous factors, which exhibit particularly intricate characteristics in the wet process. [20][21][22][23] The mechanism underlying the decomposition of lime into calcium hydroxide can be described as follows: [22,[24][25][26] CaO + H 2 O → Ca(OH) 2 (Amorphous)…”

Section: Introductionmentioning

confidence: 99%

“…During the wet digestion process for producing calcium hydroxide, both process parameters and additives can significantly impact the conversion of calcium oxide into calcium hydroxide, thereby exerting a substantial influence on the particle size of calcium hydroxide. [27][28][29] However, current research efforts in China and abroad primarily focus on the precipitation methods for preparing calcium hydroxide with high specific surface area or nanoscale, [23,[30][31][32][33] while there is a lack of systematic investigation into the influence of wet digestion process parameters and additives on the particle size of calcium hydroxide. This phenomenon has hindered fundamental research and industrial development related to calcium hydroxide.…”

Section: Introductionmentioning

confidence: 99%

“…The digestion of lime is typically a non‐catalytic solid‐liquid reaction, and therefore the conversion of calcium oxide to calcium hydroxide during digestion is influenced by numerous factors, which exhibit particularly intricate characteristics in the wet process. [ 20–23 ] The mechanism underlying the decomposition of lime into calcium hydroxide can be described as follows: [ 22,24–26 ]

\begin{equation} \mathrm{CaO}+{\mathrm{H}}_{2}\mathrm{O}\to \mathrm{Ca}(\mathrm{OH})_{2}\hspace*{0.28em}(\mathrm{Amorphous}) \end{equation}

\begin{equation} \mathrm{Ca}(\mathrm{OH})_{2}\to {\mathrm{Ca}}^{2+}+{\mathrm{OH}}^{-}\, (\mathrm{Surface}\ \mathrm{Dissolving}) \end{equation}

\begin{equation} {\mathrm{Ca}}^{2+}+{\mathrm{OH}}^{-}\to {\mathrm{Ca}}^{2+}+{\mathrm{OH}}^{-}(\mathrm{Ion}\ \mathrm{Diffusion}) \end{equation}

\begin{equation} {\mathrm{Ca}}^{2+}+{\mathrm{OH}}^{-}\to \mathrm{Ca}(\mathrm{OH})_{2}\hspace*{0.28em}(\mathrm{Crystallization}) \end{equation}

…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Particle Size of Calcium Hydroxide Prepared by Wet Digestion: Influencing Factors and Mechanism

Wang,

Wei,

Liu

et al. 2024

Cryst. Res. Technol.

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The wet dissolution process of lime is an effective approach for synthesizing calcium hydroxide. Process parameters and additives exert influence on the product particle. Among the process parameters, lime particle size, reaction temperature, and time have a significant impact on product particle size, followed by liquid‐solid ratio and stirring speed. The experiment proved that reaction time affects product particle size by affecting the crystal growth, while other process parameters affect the particle size by affecting the ion diffusion behavior. In terms of inorganic additives, Ca(OH)2 has minimal effect on product particle size; however, NaOH and CaCl2 can significantly enhance it with a greater dose leading to a larger increase. The experiment proved that Ca(OH)2, NaOH, and CaCl2 influence particle size through their impact on ion diffusion behavior. Regarding organic additives, soluble starch exhibits the greatest effect on product size followed by triethanolamine and polyvinylpyrrolidone K30. The experiment proved that soluble starch, triethanolamine, and polyvinylpyrrolidone K30 affect product particle size by influencing its crystallization position. Finally, an ultrafine slurry of calcium hydroxide was prepared using the lime wet digestion method based on the aforementioned research, with particle size distribution characterized by D10, D50, and D90 values of 0.303, 1.750, and 4.534 µm respectively.

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Effects of organic additives on calcium hydroxide crystallisation during lime slaking

Cited by 28 publications

References 79 publications

Recent Advances in Nonclassical Crystallization: Fundamentals, Applications, and Challenges

Recent Advances in Nonclassical Crystallization: Fundamentals, Applications, and Challenges

Evaluation of Ca-Based Sorbents for Gaseous HCl Emissions Adsorption

Particle Size of Calcium Hydroxide Prepared by Wet Digestion: Influencing Factors and Mechanism

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