scholarly journals Investigation on the transformation behaviours of Fe-bearing minerals of coal in O2/CO2 combustion atmosphere containing H2O

RSC Advances ◽  
2021 ◽  
Vol 11 (18) ◽  
pp. 10635-10645
Author(s):  
Fang Huang ◽  
Shanzhi Xin ◽  
Tie Mi ◽  
Liqi Zhang
Keyword(s):  
Iron Oxides ◽  
Iron Minerals ◽  
Combustion Atmosphere ◽  
Magnetite Formation

The ratio of Fe2+-glass to Fe3+-glass in ashes from O2/CO2 atmosphere is significantly increased. The iron oxides (hematite or magnetite) formation of included iron minerals may be delayed in O2/CO2. H2O promotes iron oxides formation.

Conditions of formation of the iron-containing minerals, Hällefors silver mines, Bergslagen, Sweden

1986 ◽  
Vol 50 (355) ◽  
pp. 101-110 ◽  
Author(s):  
A. W. Jasiński
Keyword(s):  
Aqueous Solutions ◽  
Iron Oxides ◽  
Iron Ore ◽  
Silver Deposit ◽  
Ore Deposit ◽  
Iron Minerals ◽  
Sulphide Precipitation ◽  
Iron Ore Deposit ◽  
Two Stages

AbstractThe Hällefors silver deposit is regarded as a volcanogenic-exhalative iron ore deposit with dispersed amounts of Ag-Pb-Zn (±Cu) which has undergone secondary remobilization leading to the concentration of sulphides and sulphosalts. Based on data from the iron oxides and sulphides, the sulphide-sulphosalt mineralization is believed to have been formed in two stages. The first is characterized by the ranges 573-473 K and 2.25–1.5 kbar, higher gradient of changes of log aS2 with temperature and mostly sulphide precipitation; the second by the ranges 473–443 K, lower gradient of changes of log aS2 and mainly sulphosalt deposition. Assuming the precipitation was from fluids and aqueous solutions, possible conditions of formation of some of the iron minerals have been determined.

scholarly journals Secondary Mineralization of Ferrihydrite Affects Microbial Methanogenesis in Geobacter-Methanosarcina Cocultures

2016 ◽  
Vol 82 (19) ◽  
pp. 5869-5877 ◽  
Author(s):  
Jia Tang ◽  
Li Zhuang ◽  
Jinlian Ma ◽  
Ziyang Tang ◽  
Zhen Yu ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Biogeochemical Cycling ◽  
Methanosarcina Barkeri ◽  
Geobacter Metallireducens ◽  
Methanogenic Activity ◽  
Content Type ◽  
Iron Minerals ◽  
Iron Mineral ◽  
Iron Mineralogy

ABSTRACTThe transformation of ferrihydrite to stable iron oxides over time has important consequences for biogeochemical cycling of many metals and nutrients. The response of methanogenic activity to the presence of iron oxides depends on the type of iron mineral, but the effects of changes in iron mineralogy on methanogenesis have not been characterized. To address these issues, we constructed methanogenic cocultures ofGeobacterandMethanosarcinastrains with different ferrihydrite mineralization pathways. In this system, secondary mineralization products from ferrihydrite are regulated by the presence or absence of phosphate. In cultures producing magnetite as the secondary mineralization product, the rates of methanogenesis from acetate and ethanol increased by 30.2% and 135.3%, respectively, compared with a control lacking ferrihydrite. Biogenic magnetite was proposed to promote direct interspecies electron transfer betweenGeobacterandMethanosarcinain a manner similar to that ofc-type cytochrome and thus facilitate methanogenesis. Vivianite biomineralization from ferrihydrite in the presence of phosphate did not significantly influence the methanogenesis processes. The correlation between magnetite occurrence and facilitated methanogenesis was supported by increased rates of methane production from acetate and ethanol with magnetite supplementation in the defined cocultures. Our data provide a new perspective on the important role of iron biomineralization in biogeochemical cycling of carbon in diverse anaerobic environments.IMPORTANCEIt has been found that microbial methanogenesis is affected by the presence of iron minerals, and their influences on methanogenesis are associated with the mineralogical properties of the iron minerals. However, how changes in iron mineralogy affect microbial methanogenesis has not been characterized. To address this issue, we constructed methanogenic cocultures ofGeobacterandMethanosarcinastrains with different ferrihydrite mineralization pathways. The experimental results led to two contributions, i.e., (i) the transformation of iron minerals might exert an important influence on methanogenesis under anaerobic conditions and (ii) both biogenic and chemical magnetite can accelerate syntrophic ethanol oxidization betweenGeobacter metallireducensandMethanosarcina barkeri. This study sheds new light on the important role of iron biomineralization in the biogeochemical cycling of carbon in diverse anaerobic environments, particularly in iron-rich natural and agricultural wetland soils.

Stabilizing pyritic material

1989 ◽  
Vol 4 ◽  
pp. 244-248 ◽  
Author(s):  
Donald L. Wolberg
Keyword(s):  
Significant Contribution ◽  
Organic Materials ◽  
Sedimentary Rocks ◽  
Iron Sulfides ◽  
Decomposition Products ◽  
Iron Minerals ◽  
Pyrite Formation ◽  
Organic Sediments ◽  
Freshwater Environments

The minerals pyrite and marcasite (broadly termed pyritic minerals) are iron sulfides that are common if not ubiquitous in sedimentary rocks, especially in association with organic materials (Berner, 1970). In most marine sedimentary associations, pyrite and marcasite are associated with organic sediments rich in dissolved sulfate and iron minerals. Because of the rapid consumption of sulfate in freshwater environments, however, pyrite formation is more restricted in nonmarine sediments (Berner, 1983). The origin of the sulfur in nonmarine environments must lie within pre-existing rocks or volcanic detritus; a relatively small, but significant contribution may derive from plant and animal decomposition products.

Selective oxidation of aniline into azoxybenzene catalyzed by Nb-peroxo@iron oxides at room temperature

2020 ◽  
Vol 44 (21) ◽  
pp. 8710-8717
Author(s):  
André L. D. Lima ◽  
Humberto V. Fajardo ◽  
André E. Nogueira ◽  
Márcio C. Pereira ◽  
Luiz C. A. Oliveira ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Selective Oxidation ◽  
Room Temperature ◽  
High Selectivity

Nb-peroxo@iron oxides show high selectivity and activity in aniline conversion to azoxybenzene.

Pilot Plant Data for Synthetic Iron Oxides

1952 ◽  
Vol 44 (3) ◽  
pp. 449-449
Author(s):  
C DeWitt ◽  
M Livingood ◽  
K Miller
Keyword(s):  
Iron Oxides ◽  
Pilot Plant ◽  
Plant Data

Effects of carbon and manganese impurities on cerium incorporation in iron oxides scales

1996 ◽  
Vol 93 ◽  
pp. 1509-1524 ◽  
Author(s):  
C Courty ◽  
H Buscail ◽  
JP Larpin
Keyword(s):  
Iron Oxides

Changes of Magnetic Characteristics of iron Oxides and Hydroxides in Aqueous Medium

2017 ◽  
Vol 39 (1) ◽  
pp. 46-52
Author(s):  
T. SAVCHENKO ◽  
◽  
A. GRECHANOVSKY ◽  
A. BRIK ◽  
N. DUDCHENKO
Keyword(s):  
Aqueous Medium ◽  
Iron Oxides ◽  
Magnetic Characteristics

IRON OXIDES FROM ELECTROFILTER ASH FOR WATER TREATMENT (ARSENIC REMOVAL)

2009 ◽  
Vol 8 (4) ◽  
pp. 895-900 ◽  
Author(s):  
Ionel Balcu ◽  
Adina Segneanu ◽  
Marius Mirica ◽  
Mirela Iorga ◽  
Catalin Badea ◽  
...  
Keyword(s):  
Water Treatment ◽  
Iron Oxides ◽  
Arsenic Removal
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