Pyrite transformation and sulfur dioxide release during calcination of coal gangue

Ge, Xinlei; Nakano, Jinichiro; Liu, Huan; Wang, Xidong; Zhang, Zuotai

doi:10.1039/c4ra06954d

Cited by 26 publications

(7 citation statements)

References 26 publications

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“…The complex peak in this temperature range [mainly for S-2(3)] with a shoulder at the lower temperature corresponding to the oxidation reaction of light hydrocarbons, while the main peak corresponds to the oxidation of heavy hydrocarbons and fixed carbon (Sun et al, 2015). Also, presence of any pyrite, might influence the TGA curve in this temperature region due to oxidation of that mineral at around 500 • C (Zhang et al, 2014). The decomposition of carbonates was observed in the DTG curve from ∼625-850 • C (dolomite 625-720 • C and calcite 780-840 • C) with mass losses of 4.1 wt.% for S-2(1) and 3.5 wt.% for S-2(3).…”

Section: Resultsmentioning

confidence: 99%

Stability of Organic Carbon Components in Shale: Implications for Carbon Cycle

et al. 2019

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Stability and mobility of organic matter in shale is significant from the perspective of carbon cycle. Shale can only be an effective sink provided that the organic carbon present is stable and immobile from the host sites and, not released easily during geological processes such as low pressure-temperature burial diagenesis and higher pressure-temperature subduction. To examine this, three Jurassic shale samples of known mineralogy and total organic carbon content, with dominantly continental source of organic matter, belonging to the Haynesville-Bossier Formation were combusted by incremental heating from temperature of 200 to 1400 • C. The samples were analyzed for their carbon and nitrogen release profiles, bulk δ 13 C composition and C/N atomic ratio, based on which, at least four organic carbon components are identified associated with different minerals such as clay, carbonate, and silicate. They have different stability depending on their host sites and occurrences relative to the mineral phases and consequently, released at different temperature during combustion. The components identified are denoted as, C-1 (organic carbon occurring as free accumulates at the edge or mouth of pore spaces), C-2 (associated with clay minerals, adsorbed or as organomineral nanocomposites; with carbonate minerals, biomineralized and/or occluded), C-3(a) (occurring with silicate minerals, biomineralized and/or occluded) and C-3(b) (graphitized carbon). They show an increasing stability and decreasing mobility from C-1 to C-3(b). Based on the stability of the different OC components, shale is clearly an efficient sink for the long term C cycle as, except for C-1 which forms a very small fraction of the total and is released at temperature of ∼200 • C, OC can be efficiently locked in shale surviving conditions of burial diagenesis and, subduction at fore arc regions in absence of infiltrating fluids. Under low fluid flux, C-3(b) can be efficiently retained as a refractory phase in the mantle when subducted. It is evident that the association and interaction of the organic matter with the different minerals play an important role in its retention in the shale.

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Section: Resultsmentioning

confidence: 99%

Stability of Organic Carbon Components in Shale: Implications for Carbon Cycle

et al. 2019

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“…Iron-bearing substances such as pyrite undergo the following chemical reaction [ 42 ]: 4FeS 2 (pyrite) + 11O 2 → 2Fe 2 O 3 + 8SO 2 …”

Section: Resultsmentioning

confidence: 99%

Preparation of Poly Aluminum-Ferric Chloride (PAFC) Coagulant by Extracting Aluminum and Iron Ions from High Iron Content Coal Gangue

et al. 2022

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Poly aluminum-ferric Chloride (PAFC) is a new type of high efficiency coagulant. In this study, high iron type gangue is used as a main raw material. It is calcined at 675 °C for 1 h and 3% CaF2 is added to the calcined powder and reacted with 20% hydrochloric acid at 93 °C for 4 h. The leaching ratio of aluminum ions is 90% and that of iron ions is 91%. After Fe2+ ions are oxidized in the filtrate, CaCO3 is used to adjust the pH of the filtrate to 0.7. The microwave power is adjusted to 80 W and the filtrate is radiated for 5 min. After being aged for 24 h, PAFC product is obtained. The prepared PAFC is used to treat mine water and compared with the results of PAC and PAF, the turbidity removal ratio of PAFC is 99.6%, which is greater than 96.4% of PAC and 93.7% of PAF. PAFC is a mixture with different degrees of polymerization. It demonstrates that extracting aluminum and iron ions from high iron content gangue to prepare PAFC by microwave is efficient and feasible.

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“…Overall, the total heat release is larger than the heat absorption, which exhibits an exothermic peak. On the TG curve, the quantity decreases significantly for the combustion of coal and pyrite which produce CO2, SO2, H2O, and other volatile substance products [33]. Meanwhile, siderite is decomposed into FexOy, CO2, or CO, and the volatilizations Overall, the total heat release is larger than the heat absorption, which exhibits an exothermic peak.…”

Section: Tg-dsc Analyses Of the Coal Ganguementioning

confidence: 99%

“…Meanwhile, siderite is decomposed into FexOy, CO2, or CO, and the volatilizations Overall, the total heat release is larger than the heat absorption, which exhibits an exothermic peak. On the TG curve, the quantity decreases significantly for the combustion of coal and pyrite which produce CO 2 , SO 2 , H 2 O, and other volatile substance products [33]. Meanwhile, siderite is decomposed into Fe x O y , CO 2 , or CO, and the volatilizations lead to the quantity loss.…”

Section: Tg-dsc Analyses Of the Coal Ganguementioning

confidence: 99%

Extraction of Aluminum and Iron Ions from Coal Gangue by Acid Leaching and Kinetic Analyses

et al. 2022

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Extracting valuable elements from coal gangue is an important method for the utilization of coal gangue. In order to obtain the suitable technological conditions and the acid leaching kinetic model of leaching aluminum and iron ions from high-iron and low-aluminum coal gangue, the effects of calcination temperature, calcination time, and acid types on the leaching results of aluminum and iron ions are studied. The results show that when the gangue is calcined at 675 °C for 1 h, then the calcined gangue powder is leached by 6 mol/L hydrochloric acid at 93 °C for 4 h, the leaching ratio of iron ions is more than 90%, and that of aluminum ions is more than 60%. Furthermore, the acid leaching kinetic equations at 30 °C, 50 °C, 70 °C, and 90 °C are studied by three kinetic models, and the apparent activation energies of the reactions are calculated by the Arrhenius formula. The results show that the leaching behavior of aluminum and iron ions conformed to the “mixing control” model equation: “(1 − x)−1/3 − 1 + 1/3ln(1 − x) = kt + b”. The apparent activation energies of aluminum and iron ions are 55.5 kJ/mol and 55.8 kJ/mol, respectively. All these indicate that the acid leaching process is controlled by the “mixing control”.

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Pyrite transformation and sulfur dioxide release during calcination of coal gangue

Abstract: The SO2 emission behavior of coal gangue during calcination was systematically investigated.

Cited by 26 publications

References 26 publications

Stability of Organic Carbon Components in Shale: Implications for Carbon Cycle

Stability of Organic Carbon Components in Shale: Implications for Carbon Cycle

Preparation of Poly Aluminum-Ferric Chloride (PAFC) Coagulant by Extracting Aluminum and Iron Ions from High Iron Content Coal Gangue

Extraction of Aluminum and Iron Ions from Coal Gangue by Acid Leaching and Kinetic Analyses

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