Occurrence Characteristics of Fine-Grained Pyrite in Coal and Its Scaling Effect on Flotation Desulfurization

Ma, Mengya; Wang, Wenfeng; Zhang, Kun

doi:10.1021/acsomega.2c05698

Cited by 6 publications

(3 citation statements)

References 42 publications

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“…Iron in coal is primarily present as pyrite (Fe 2 S 2 ) in coal. In presence of acid, pyrite typically gets fragmented into sulphate and iron oxyhydroxides (Ma et al 2022). Mineral acids (~ 0.5-1 M) are usually employed to study the chemical reactions of pyrite.…”

Section: Complex/carbonate Bound Elementsmentioning

confidence: 99%

Petrology and association of rare earth elements in magmatically altered high-ash coal of Indian origin

Banerjee,

Chakladar,

Kumar

et al. 2024

Int J Coal Sci Technol

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The extraction of valuables from waste has gained momentum. Thermal influence alters both the organic and inorganic components of coal. Insufficient knowledge on the association of rare earth elements (REEs) with the parent matrix of thermally altered high-ash coals (63% ash) limits the potential for such coals being utilized for isolation of valuables. In this study, we analyzed the distribution and occurrence modes of REEs within a magmatically altered high-ash coal via nine-step sequential extraction, combining Tessier and BCR methods. The total concentration of REEs in the coal sample, on whole coal basis, was found to be 820 ppm, which is significantly higher than the world average. Major mineral oxides were deduced to be those of Si, Fe, Al, Ca, Mg, and Ti. Sequential extraction confirmed that about 66% of HREE and 25% of LREE were included in the residual fraction. LREEs were concluded to be primarily in ionic form, whereas HREEs were speculated to be associated with the TiO2 phase. XRD analyses showed that thermal alteration affected the dolomite phase specifically, which selectively got removed where carbonate-bound elements were assessed. Petrographic analysis supported the magmatic influence and demonstrated the presence of mosaic structures and pores containing unfused vitrinite, with a reflectance value of 3.6. To summarize, the present study pertaining to delineation of association of valuables in high-ash heat-altered coals from an Eastern coalfield in India can potentially open up new avenues for utilizing such coals, which are otherwise considered waste.

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Section: Complex/carbonate Bound Elementsmentioning

confidence: 99%

Petrology and association of rare earth elements in magmatically altered high-ash coal of Indian origin

Banerjee,

Chakladar,

Kumar

et al. 2024

Int J Coal Sci Technol

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“…The condition of biological desulphurization is harsh, and the chemical method is more suitable for deep desulphurization. The coal liquefaction residue is produced in dense flake form, which limits the application of physical desulfurization technology, such as flotation technology [ 22 ]. Organic sulfur is suitable for chemical removal by thermochemical oxidation to convert organic sulfur to sulfur-containing gases such as SO 2 and SO 3 , or by electrochemical reduction to H 2 S and S 2− [ 23 , 24 ], and by electrochemical oxidation to convert organic sulfur to soluble sulfonic acid and sulfate [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Electrochemical Desulfurization of Coal Liquefaction Residue

Jiang

Zhang

et al. 2023

Molecules

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The occurrence of sulfur in coal direct liquefaction residue affects its further high quality and high value utilization. Electrochemical desulfurization is characterized by mild reaction conditions, simple operation, easy separation of sulfur conversion products and little influence on the properties of the liquefied residue. An anodic electrolytic oxidation desulphurization experiment was carried out on the liquefaction residue of the by-product of a coal-to-liquid enterprise in the slurry state. An electrochemical test and material characterization of raw materials before and after electrolysis showed that electrolytic oxidation can desulfurize the liquefaction residue under an alkaline condition. Linear sweep voltammetry (LSV) was used for the electrolysis experiments to obtain the optimal slurry concentration of 60 g/L. On this basis, the reaction kinetics were calculated, and the minimum activation energy in the interval at 0.9 (V vs. Hg/HgO) was 19.71 kJ/mol. The relationship between the electrolytic desulfurization of the liquefied residue and energy consumption was studied by the potentiostatic method. The influence of anodic potential and electrolytic temperature on the current density, cell voltage, desulfurization rate and energy consumption was investigated. The experimental results showed that the desulfurization rate and total energy consumption increase positively with the increase in reaction temperature and electrolytic potential in a certain range. The influence of the reaction temperature on the desulfurization rate and total energy consumption is more prominent than that of electrolytic potential, but the energy consumption of sulfur removal per unit mass does not show a positive correlation. Therefore, with the energy consumption per unit mass of sulfur removal as the efficiency index, the optimal experimental results were obtained: under the conditions of 0.8 (V vs. Hg/HgO) anode potential, 50 °C electrolytic temperature, 60 g/L slurry concentration and 14,400 s electrolytic time, the desulfurization rate was 18.85%, and the power consumption per unit mass of sulfur removal was 5585.74 W·s/g. The results of XPS, SEM, BET and IC showed that both inorganic and organic sulfur were removed by electrolytic oxidation, and the morphology, pore structure and chemical bond of the liquefied residue were affected by electrolytic oxidation. The research method provides a new idea and reference for the efficiency evaluation of desulfurization and hydrogen production from coal liquefaction residue.

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“…As a low-grade resource, the processing of low-rank coal (LRC) has been paid more and more attention. − Efficient and full utilization of LRC is of great significance to understand green and low-carbon cycle development. − Flotation plays an important role in the recovery of fine-grained LRC. − However, the flotation efficiency still needs to be improved, and there is an urgent need to find more factors restricting flotation and solve it. − …”

Section: Introductionmentioning

confidence: 99%

New Insight into Temperature Effects on Low-Rank Coal Flotation Using Diesel as a Collector

et al. 2023

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Efficient flotation of low-rank coal is of great significance for the development of green and low-carbon cycles. Temperature is a crucial parameter of flotation, but the mechanism of its effect on flotation lacks understanding. In this paper, the mechanism was studied by kinetic flotation, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, low-temperature liquid-nitrogen adsorption (LP-N 2 A), X-ray photoelectron spectroscopy (XPS), and molecular dynamics simulation. The flotation combustible recovery gradually decreases as temperature rises. Compared with 60 °C, the combustible recovery at 5 °C increases by 18.13%. The desorption energy for oil droplets decreases as the temperature rises. As a result, the oil droplets are easier to desorb at high temperatures. The SEM and LP-N 2 A results demonstrate that the pores and fractures of the coal sample are well developed. Also, the oil−water interfacial tension and viscosity of oil droplets decrease as the temperature rises, while the diffusion ability increases. These increase the volume of oil droplets that penetrate into the pores, resulting in poor spreadability of oil droplets on the coal surface. The average volume of bubbles gradually increases as temperature rises, which renders the flotation foam unstable and worsens the flotation. Therefore, the flotation performance is better at low temperatures.

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Occurrence Characteristics of Fine-Grained Pyrite in Coal and Its Scaling Effect on Flotation Desulfurization

Cited by 6 publications

References 42 publications

Petrology and association of rare earth elements in magmatically altered high-ash coal of Indian origin

Petrology and association of rare earth elements in magmatically altered high-ash coal of Indian origin

Experimental Study on Electrochemical Desulfurization of Coal Liquefaction Residue

New Insight into Temperature Effects on Low-Rank Coal Flotation Using Diesel as a Collector

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