FTIR analysis of water structure and its influence on the flotation of arcanite (K2SO4) and epsomite (MgSO4·7H2O)

Cheng, Fangqin; Cao, Qinbo; Guan, Yong; Cheng, Hao; Wang, Xuming

doi:10.1016/j.minpro.2013.04.007

Cited by 67 publications

(42 citation statements)

References 15 publications

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“…The raw lignin sample exhibited a strong broad peak at 3368 cm −1 ( Figure 2 a), which is attributed to the stretching vibrations of hydroxyl groups in phenolic and aliphatic side chains. The stronger hydroxyl peak might also have been partially contributed by the moisture trapped in tangled lignin chains [ 23 ]. Kraft lignin is recovered from black liquors through the acidity precipitation process, where the condensed lignin chains are twisted and entangled, forming a huge 3-D structure, and a portion of water molecules are held and trapped in the lignin particles during its isolating/extraction process.…”

Section: Resultsmentioning

confidence: 99%

Effect of Solvents on Fe–Lignin Precursors for Production Graphene-Based Nanostructures

Yan

Cai

2020

Molecules

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Kraft lignin was catalytically graphitized to graphene-based nanostructures at high temperature under non-oxidative atmospheres. To obtain the best catalytic performance, a uniform catalyst–lignin mixture must be made by bonding transitional metal (M) ions to oxygen (O), sulfur (S) or nitrogen (N)-containing functional groups in kraft lignin. One of the strategies is to dissolve or disperse kraft lignin in a suitable solvent, whereby the polymer chains in the condensed lignin molecules will be detangled and stretched out while the functional groups are solvated, and when mixing lignin solution with catalyst metal solution, the solvated metal ions in an aqueous solution can diffuse and migrate onto lignin chains to form M-O, M-S, or M-N bonds during the mixing process. Therefore, solvent effects are important in preparing M–lignin mixture for production of graphene-based nanostructures. Fe–lignin precursors were prepared by dissolving lignin with different solvents, including water, methanol, acetone, and tetrahydrofuran (THF). Solvent effects on the catalytic performance, size and morphology of graphene-based nanostructures were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HRTEM), and nitrogen sorption measurements. The sizes, morphologies, and catalytic properties of the products obtained from Fe–lignin precursors are greatly influenced by the solvents used. It was found that Fe–lignin (THF) had the highest iron dispersion and the smallest iron particle size. Furthermore, Fe–lignin (THF) exhibited the best catalytic performance for graphitization of kraft lignin while the graphitization degree decreased in the order: Fe–lignin(THF) > Fe–lignin(Acetone) > Fe–lignin(methanol) > Fe–lignin(water).

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Section: Resultsmentioning

confidence: 99%

Effect of Solvents on Fe–Lignin Precursors for Production Graphene-Based Nanostructures

Yan

Cai

2020

Molecules

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“…A notable positive change in the thermodynamic parameter in dispersion process is a driver of the absorption of flotation reagents on the surface of minerals [3]. According to [4] when MgSO4 and Na2SO4 are floated by means of anionic or cation collectors the best flotation effect is observed in MgSO4 salt that disrupts water structure on the power surface. Thus, the properties determined by structural organization of anionic and cation hydration water should be characterized as the internal size effect.…”

Section: Introductionmentioning

confidence: 99%

Influence of Size Effects on the Properties of Processed Iron Ore and Schungite Rock

Mirgorod¹,

Емельянов²,

Fedosjuk³

et al. 2016

J. Nano- Electron. Phys.

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Scanning electron microscopy, energy dispersion spectroscopy, X-ray diffractometry and magnetometry methods were used to investigate the structure and magnetic properties of iron ore and schungite rock. The results show the existence of external size effect in iron ore concentrate. It is related with the penetration of iron nanoparticles from equipment surfaces onto the powder surface, which increases specific magnetic saturation of the powder by 1.6 times compared with pure magnetite. As a result of internal size effect in schungite powder its reactivity decreases by 800 С and after heat treatment of the powder its specific magnetic saturation increases by seven times. Considering the application of size effects the investigated powders and waste natural mineral powders are recommended to be used in the production of composite materials.

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“…Different spectroscopic methods have been applied to understand interfacial water structure at mineral surfaces. For example, the interfacial water structure at soluble salt surfaces has been studied with Fourier transform infrared spectroscopy (FTIR) (Cao et al, 2011;Cheng et al, 2013;Yalamanchili et al, 1991). Also, vibrational sum-frequency generation spectroscopy (SFG) has been used to explore the structure of water molecules at oxide mineral surfaces (Ostroverkhov et al, 2005;Shen, 1994;Shen and Ostroverkhov, 2006;Yeganeh et al, 1999) and fluorite surfaces (Eftekhari-Bafrooei and Borguet, 2009;Zhang et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Effect of surface oxidation on interfacial water structure at a pyrite (100) surface as studied by molecular dynamics simulation

Jin

Miller

Dang

et al. 2015

International Journal of Mineral Processing

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In the first part of this paper, a SEM and contact angle study of a pyrite (100) surface is reported describing the relationship between surface oxidation and the hydrophilic surface state. In addition to these experimental results, the following simulated surface states were examined using molecular dynamics simulation (MDS): a fresh unoxidized (100) surface; polysulfide at the (100) surface; and elemental sulfur at the (100) surface. Crystal structures for the polysulfide and elemental sulfur at the (100) surface were simulated using density functional theory (DFT) quantum chemical calculations. The well known oxidation mechanism which involves formation of a metal deficient layer was also described with DFT. Our MDS results of the behavior of interfacial water at the fresh and oxidized pyrite (100) surfaces without/with the presence of ferric hydroxide include simulated contact angles, number density distribution for water, water dipole orientation, water residence time, and hydrogenbonding considerations. The significance of the formation of ferric hydroxide islands in accounting for the corresponding hydrophilic surface state is revealed not only from experimental contact angle measurements but also from simulated contact angle measurements using MDS. The hydrophilic surface state developed at oxidized pyrite surfaces has been described by MDS, on which basis the surface state is explained, based on interfacial water structure.

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FTIR analysis of water structure and its influence on the flotation of arcanite (K2SO4) and epsomite (MgSO4·7H2O)

Cited by 67 publications

References 15 publications

Effect of Solvents on Fe–Lignin Precursors for Production Graphene-Based Nanostructures

Effect of Solvents on Fe–Lignin Precursors for Production Graphene-Based Nanostructures

Influence of Size Effects on the Properties of Processed Iron Ore and Schungite Rock

Effect of surface oxidation on interfacial water structure at a pyrite (100) surface as studied by molecular dynamics simulation

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