Flotation separation of quartz from collophane using an amine collector and its adsorption mechanisms

2020

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Surface roughness has an important influence on the wettability of particles. This paper is an innovative exploration to control the surface wettability of apatite and dolomite from the perspective of roughness in the background of phosphate flotation. Roughness characteristics of apatite and dolomite particles and its effects on wettability were investigated with surface roughness, contact angle measurements, and SEM analysis. The relationship between surface energy and wettability of different roughness surfaces was also discussed. The results indicated that the influence of roughness on apatite and dolomite particles showed the same regularity, and wettability increased with the increasing roughness for hydrophilic surfaces, while the wettability decreased for hydrophobic surfaces. The influence of roughness on wettability can be well explained by Wenzel and Cassie models, and the surface energy of different rough surfaces had a strong correlation with their wettability. When sodium oleate was added after acid treatment, the apatite was hydrophilic, while the dolomite was hydrophobic; the difference in wettability between them became greater as surface roughness increased. Thus, it can be predicted that the selective separation of dolomite and apatite under acid reverse flotation conditions can be strengthened by increasing the mineral surface roughness during comminution.

Section: Surface Tension Measurementsmentioning

confidence: 99%

Insight into the Influence of Surface Roughness on the Wettability of Apatite and Dolomite

2020

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“…The surface structures and characteristics of quartz crystal have been investigated extensively using traditional means of analysis technologies, such as X-ray diffraction [10], scanning electron microscope [11], and photoelectron spectrum [12], but these studies have failed to offer more detailed surface structural and electronic properties at the level of electron and atom due to the limited resolution or accuracies of the above analysis methods. Even though atomic force microscopy can provide an overall characterization of the surface topography of a quartz (001) surface on a nanometer scale [13] and offer images of synthetically grown-quartz (0001) surfaces [14], it still fails to further determine the detailed microstructure of the exposing atoms on surface.…”

Section: Introductionmentioning

confidence: 99%

Structural and Electronic Properties of Different Terminations for Quartz (001) Surfaces as Well as Water Molecule Adsorption on It: A First-Principles Study

et al. 2018

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Structural and electronic properties of Si termination, O-middle termination, and O-rich terminations of a quartz (001) surface as well as water molecule adsorption on it were simulated by means of density functional theory (DFT). Calculated results show that the O-middle termination exposing a single oxygen atom on the surface is the most stable model of quartz (001) surface, with the lowest surface energy at 1.969 J·m −2 , followed by the O-rich termination and Si termination at 2.892 J·m −2 and 2.896 J·m −2 , respectively. The surface properties of different terminations mainly depend on the surface-exposed silicon and oxygen atoms, as almost all the contributions to the Fermi level (E F ) in density of states (DOS) are offered by the surface-exposed atoms, especially the O2p state. In the molecular adsorption model, H 2 O prefers to adsorb on the surface Si and O atoms, mainly via O 1 -H 1 bond at 1.259 Å and Si 1 -O w at 1.970 Å by Van der Waals force and weak hydrogen bond with an adsorption energy of −57.89 kJ·mol −1 . In the dissociative adsorption model, the O-middle termination is hydroxylated after adsorption, generating two new Si-OH silanol groups on the surface and forming the O w H 2 ···O 4 hydrogen bond at a length of 2.690 Å, along with a large adsorption energy of −99.37 kJ·mol −1 . These variations in the presence of H 2 O may have a great influence on the subsequent interfacial reactions on the quartz surface.

“…Furthermore, SIROQUANT software (V3, Sietronics) was carried out to quantify the mineralogical composition. The software used the full-profile Rietveld method to refine the shape of calculated XRD pattern against the profile of a measured pattern [21].…”

Section: X-ray Diffraction (Xrd) Analysismentioning

confidence: 99%

Geochemical Characteristics of Dolomitic Phosphorite Containing Rare Earth Elements and Its Weathered Ore

et al. 2019

In order to provide a good theoretical guidance for the development and utilization of weathered phosphorite resources, we investigated the geochemical and mineralogical characteristics of primary and weathered phosphorites. The analysis of trace elements showed that the primary ore has hydrothermal sedimentation effect in the later stage, the weathered ore has obvious residual enrichment and the phosphate ore belongs to clastic lithologic phosphate rock. In addition, through leaching test method, it was shown that rare earth elements are present in fluorapatite in the form of isomorphic substitution, and the proportion of rare earth elements adsorbed on clay and other minerals was likely to be between 2% and 3%. The light rare earth elements are relatively enriched in both primary and weathered phosphorite, and Ce and Eu have obvious negative anomalies. The primary phosphorite is a dolomitic phosphorite containing rare earth elements, which are naturally enriched by weathering, and its weathered ore has obvious residual enrichment, while the deposit was characterized by normal marine sedimentation and hydrothermal action.