Density functional theory calculation of fracture surfaces of siderite and hematite

Yuan, Zhulin; Zhang, Chen; Li, Lixia; Xu, Xiaoguang; Wang, Xüming

doi:10.1016/j.powtec.2020.08.041

Cited by 5 publications

(4 citation statements)

References 33 publications

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“…For hematite, Gao et al believed that (012) and (104) were the major exposed surfaces, which is consistent with the report of Guo et al, who observed clear lattice fringes of hematite nanoparticles with a dihedral angle of 86° by a high-resolution transmission electron microscope (HR-TEM), thus confirming the dominant position of the hematite (012) surface. However, Yuan et al predicted that (110), (101), and (011) were the main fracture surfaces of hematite from the perspective of mechanical properties. In addition, it is reported that the Fe-terminated surface of the (001) plane is also considered a potential exposed surface. − …”

Section: Introductionmentioning

confidence: 99%

Insights into the Fracture Nature of Hematite from First Principles DFT Calculations

et al. 2023

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Hematite, as an important iron source, usually crystallizes in the structure of rhombohedral R3̅ c in nature. To date, reports on the major exposed surface of hematite are still inconclusive. Herein, the fracture nature of hematite is studied by the density functional theory (DFT) method. The fracture surface morphology analysis predicts the fracture dominance of the (012) plane structurally. Besides, the lowest surface broken bond density (D b ) and the surface energy among all of the investigated surfaces also establish the exposure priority of the (012) surface. In addition, the ( 110) and ( 104) surfaces also show a strong fracture potential. In our proposed partition model, the exposure priority of ( 110) and ( 104) surfaces in region 2 with a lower surface energy and surface broken bond density is second only to the (012) surface. The other surfaces, except for the (012), (110), and (104) surfaces, are divided into region 3; here, the exposure of the surfaces located in this region is considered to be uncompetitive.

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Section: Introductionmentioning

confidence: 99%

Insights into the Fracture Nature of Hematite from First Principles DFT Calculations

et al. 2023

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“…The crystal mechanical property of metal materials has been conducting numerous studies; meanwhile, the mechanical property of nonmetallic minerals on a crystal scale has become a hot-spot field gradually. Yuan et al 16 and Zhang et al 17 studied the mechanical properties and fracture surface of Siderite and hematite, which revealed that the defects did not affect the symmetry of the distribution of mechanical properties. Heyliger et al 18 measured the elastic constant of a natural quartz sphere via resonance-ultrasound spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

New Insight into Elastic Mechanical Properties and Anisotropies of Crystal Defect α-Quartz from DFT Calculation

Zhang,

Jiao,

Qin

et al. 2023

ACS Omega

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To reveal the cleavage mechanism of α-quartz in the grinding process of nonferrous metal ores, mechanical and charge properties of α-quartz crystals are investigated using the density functional theory. Based on the elastic constant matrix, the bulk and shear moduli were calculated before and after the α-quartz with oxygen atom defects. The results show that the ratios of bulk and shear moduli (B/G) were 0.87 and 0.95, respectively, which indicated that at the same stress level, it was easier to fracture without O-vacancy defects than with O-vacancy defects. The mapping surfaces indicated that the O-vacancy defect increased the bulk-, shear-, and Young's moduli, and Poisson ratio while decreasing the hardness. The anisotropy index (A L and A U ) was calculated which illustrated that the O-vacancy can result in an increased anisotropy; meanwhile, the bulk anisotropy index (A B ) increased strongly about two times. The anisotropy analysis shows the dominance crystal cleavage of the (011) plane in the shear stress and the dominance crystal cleavage of the (111) plane in the normal stress. The electron localization function α-quartz show that the O-vacancy defect can decrease the Si−Si length from 3.703 to 2.442 Å, which indicated that the O-vacancy formed the new covalent bonds between silicon atoms. Our work provided a systematic approach containing the mechanical, anisotropic, and electronic properties of mineral crystals to explain the cleavage behavior of crystals.

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“…La Figura 15 indica que la disposición antiferromagnética (+−−+) presenta la energía más baja, por lo cual es la configuración magnética más estable y en consecuencia es la configuración magnética que con mayor probabilidad se encuentra en la naturaleza. Estos resultados son consistentes con trabajos teóricos previos [72,89,98].…”

Section: Resultados Y Discusión Etapa 1 Estudio Del Materials Adsorbenteunclassified

“…defectos en los cristales afectan en gran medida sus propiedades termodinámicas, eléctricas, magnéticas y mecánicas [89].…”

Section: Adsorbenteunclassified

Rol de los planos cristalográficos {0001} y {0112} de la α-Fe₂O₃ en la remoción del arsénico

Pérez¹

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Ante la necesidad de desarrollar técnicas asequibles y eficientes para eliminar el arsénico (As) de cuerpos de agua y así proteger la salud humana, el presente trabajo es un estudio teórico que da continuidad a la investigación experimental realizada por Garay-Rodríguez en el año 2018, quien estudio la remoción de los iones As (III) y As (V) presentes en el agua para consumo humano por el proceso de adsorción, empleando como material adsorbente una zeolita natural tipo clinoptilolita del estado de Oaxaca modificada químicamente con óxidos de hierro (principalmente en su fase hematita, α-Fe₂O₃). Con el fin de crear un modelo representativo que pueda ser manipulado para mejorar la eficiencia en el proceso de remoción de contaminantes, específicamente compuestos de arsénico. La presente investigación implementa un enfoque basado en la química cuántica, donde la energía total de un sistema esta descrita como función de la densidad electrónica, para esto se utiliza la teoría de funcionales de la densidad —DFT por sus siglas en inglés— que ha demostrado ser una herramienta potente para el análisis y explicación de los resultados generados experimentalmente. La primera etapa de esta investigación abarco el estudio de las propiedades geométricas y electrónicas que surgen de la complejidad de los compuestos de óxido de hierro como material adsorbente. Resultando en que el estado magnético más estable de la α- Fe₂O₃ es el estado antiferromagnético (+ − − +) y, por lo tanto, el estado magnético de la α- Fe₂O₃ a condiciones estándar (1 atm de presión y 25 ˚C de temperatura). Por otro lado, se demostró que los planos [0001] y [0112] están presentes en el material en bulk debido a su baja diferencia energética. Finalmente, la segunda etapa consistió en un estudio de la fuerza de adsorción teórica de los iones As (III) (arsenito) y As (V) (arsenato) tanto en la superficie {0001} como la superficie {0112}, debido a que cada una de estas superficies presenta diferente reactividad en la remoción de estos contaminantes de los mantos acuíferos.

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Density functional theory calculation of fracture surfaces of siderite and hematite

Cited by 5 publications

References 33 publications

Insights into the Fracture Nature of Hematite from First Principles DFT Calculations

Insights into the Fracture Nature of Hematite from First Principles DFT Calculations

New Insight into Elastic Mechanical Properties and Anisotropies of Crystal Defect α-Quartz from DFT Calculation

Rol de los planos cristalográficos {0001} y {0112} de la α-Fe₂O₃ en la remoción del arsénico

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