A novel method for surface wettability modification of talc through thermal treatment

Yi, Hao; Zhao, Yunliang; Liu, Yiping; Wang, Wei; Song, Shaoxian; Liu, Cheng; Li, Hongqiang; Zhan, Weiquan; Liu, Xin

doi:10.1016/j.clay.2019.04.023

Cited by 29 publications

(14 citation statements)

References 54 publications

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“…In the case of trioctahedral structures (talc), the degree of hydrophobicity can vary depending on the relative humidity (Michot et al, 1994;Rotenberg et al, 2011) or external pressure on the system (Wang et al, 2004;2005a). Thermal treatment (>900 o C) can also significantly affect the hydrophobicity of talc, due to the disordering of silica tetrahedron structures and formation of amorphous silica phases (Yi et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Intrinsic hydrophobicity of smectite basal surfaces quantitatively probed by molecular dynamics simulations

Szczerba

Kalinichev

Kowalik

2020

Applied Clay Science

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Section: Introductionmentioning

confidence: 99%

Intrinsic hydrophobicity of smectite basal surfaces quantitatively probed by molecular dynamics simulations

Szczerba

Kalinichev

Kowalik

2020

Applied Clay Science

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“…21 In any case, all studies conclude that the optimal catalyst for the Lebedev process must strike a delicate balance between acidic and base sites. 8,[13][14][15]17,18,[21][22][23][24] Even after more than 70 years, however, the fundamental details of how wet-kneading generates the active sites for butadiene formation and corresponding silica-magnesia phases have not been fully elucidated.…”

mentioning

confidence: 99%

Origin of active sites on silica–magnesia catalysts and control of reactive environment in the one-step ethanol-to-butadiene process

Chung

Shoinkhorova

et al. 2023

Nat Catal

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Wet-kneaded silica-magnesia is a benchmark catalyst for the one-step ethanol-to-butadiene Lebedev process. Magnesium silicates, formed during wet-kneading, have been proposed as active sites responsible for butadiene formation, and their catalytic performance has been mainly explained by the variations in the ratio of acid and base sites. While the Lebedev process was developed in the 1930s, However, a detailed insight into how the peculiar, yet essential wet-kneading synthesis leads to the generation, location, and catalytic role of magnesium silicates has not been fully established. Here, we demonstrate that magnesium silicates formation occurs via dissolution of Si and Mg subunits from SiO2 and Mg(OH)2 precursors, initiated by the alkaline pH of the aqueous wet-kneading medium, followed by cross-deposition of the dissolved species on the precursor surfaces. Building on these new insights, two individual model systems (Mg/SiO2 and Si/MgO) were synthesized, representative of the constituents of the wet-kneaded silica-magnesia catalyst, by selective dissolution/deposition induced by pH alteration of the aqueous wet-kneading medium. Using these model catalysts, we demonstrate that the location of the magnesium silicates (i.e., Mg on SiO2 or Si on MgO) governs not only their chemical nature but also the ethanol adsorption configuration, which ultimately cause the catalyst material to be selective mainly for ethylene or butadiene. We demonstrate close proximity at the particle level of the of acid and basic sites is a prerequisite to promote the butadiene formation. The insights gained from the new structure-performance relationships that correlate catalytic activity with types and nature of

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“…To address this, Yi et al (2019) applied thermal treatment (calcination at 960 • C) instead of surfactants that break the siloxane structure to amorphous silica. By thermal treatment, the surface wettability changed from 68.87 • to 55.34 • attributed to the transformation from the siloxane structure (hydrophobic) to amorphous silica (hydrophilic) [99,100].…”

Section: Pre-treatmentmentioning

confidence: 99%

Talc Flotation—An Overview

et al. 2021

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Talc is a naturally hydrophobic gangue mineral in most sulfide ores. However, talc has vast applications in the cosmetics, paper, and paint industries due to its high chemical stability, and its demand continues to grow. Since flotation is the most effective beneficiation technique for upgrading sulfides, the high hydrophobicity of talc has made its selective separation challenging. This paper explored the different properties of talc and the different factors that affect its flotation separation performance as a proven versatile beneficiation technique. Surface properties, zeta potential measurements, contact angles, and other factors affecting the talc flotation efficiency were discussed in detail. It was observed that the surface face/edge ratio (particle size) has a direct relationship with the level of talc hydrophobicity. Talc surfaces are negatively charged in a wide pH range (pH 2–12). Different depressants have already been studied; however, most of them showed low selectivity. The addition of ions such as Ca2+ could enhance talc depression. Pretreatment methods such as ultrasonic and thermal treatments were reported to decrease the talc floatability. It was demonstrated that the development of new selective depressants or pretreatment options for talc flotation requires attention in future investigations to improve its selective separation.

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A novel method for surface wettability modification of talc through thermal treatment

Cited by 29 publications

References 54 publications

Intrinsic hydrophobicity of smectite basal surfaces quantitatively probed by molecular dynamics simulations

Intrinsic hydrophobicity of smectite basal surfaces quantitatively probed by molecular dynamics simulations

Origin of active sites on silica–magnesia catalysts and control of reactive environment in the one-step ethanol-to-butadiene process

Talc Flotation—An Overview

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