Menu
As the oxygen accessibility increases during the pyrites thermal decomposition Equation 3 hematite Fe 2 O 3 as the main oxidation product and the most stable iron oxide at ambient condition forms while any restriction in oxygen availability causes pyrite to mainly transform to magnetite Fe 3 O 4 Equation 4 20262829
Get Price
In Pat No 4 052 170 a process for magnetic desulfurization of coal is taught which includes the steps of heating the coal with hot oxygen containing gas to 480° 600° C to enhance the magnetic susceptibility of the pyrites and removing the pyrites in an at least 10 kilogauss approx 10 000 Oe magnetic separation means
Get Price
The thermal phase transition of pyrite from coal was studied using thermogravimetry and derivative thermogravimetric infrared spectroscopy and X ray diffraction XRD According to the XRD results the phase transition of the pyrite starts at 350 °C pyrrhotite and magnetite are intermediate products of the oxidation from pyrite to hematite
Get Price
The oxidation of large octahedral single crystals of magnetite extracted from chlorite shale at Shabrovsk talc mine Middle Urals is experimentally studied Differential heating curves show that the processes occurring in the oxidative roasting of magnetite Fe3O4 are highly reproducible The mechanism of martensite oxidation is considered as well as the temperature ranges corresponding to
Get Price
The mechanism of pyrite oxidation may therefore be written as a series of steps 1 Preferrential release of ferrous ions to form a reacted sulfur layer S FeS2 → S Fe 2 e …………………………………………………… 11 2 Hydrolysis of ferrous ions to form ferrous hydroxide Fe 2 OH Fe OH 2………………………………………………… 12 3
Get Price
What is pyrite used for in everyday life The main uses today include Production of sulphur dioxide for the paper of sulphuric acid for the chemistry industry and the fertilized industry Pyrite is most often mined for the gold copper or other elements associated with it
Get Price
What is pyrite made out of Pyrite is composed of iron and sulfur however the mineral does not serve as an important source of either of these elements Iron is typically obtained from oxide ores such as hematite and magnetite
Get Price
Pyrite undergoes electrochemical reactions in coal as shown in Fig 6 When the electrochemical oxidation of pyrite continues to apply an external electric field to the coal the coal body appears
Get Price
Abstract When bituminous coal is heated in an inert atmosphere He containing small amounts of oxygen at 393 455 °C pyrite FeS 2 in coal is partially converted to magnetite Fe 3 0 4 The maximum amount of Fe 3 0 4 formed during the time of heating corresponds to 5 20% of the total pyrite present depending on the coal sample
Get Price
Pyrite has recently been shown to spontaneously generate hydrogen peroxide H 2 O 2 [32 33] and hydroxyl radicals • OH [23 24] when placed in formation of these reactive oxygen species ROS also explains the recent observation that aqueous pyrite slurries degrade yeast RNA ribosomal RNA and DNA [] Pyrite is thought to form H 2 O 2 through the iron catalyzed Haber Weiss
Get Price
A project was undertaken to characterize the oxidation of iron pyrite to the non slagging species magnetite during pulverized coal combustion The work was aimed at defining the pyrite transformations responsible for the higher slagging propensity of staged low NO {sub x} pulverized coal combustor burners
Get Price
Beneficiation of sulphide ores by flotation is ascribed to the natural electrochemical activity associated with sulphide minerals Flotation is an electrochemical process comprising many interdependent conditions that are difficult to decouple in terms of controlling flotation performance The extent of electrochemical activity is mineral dependent and can be measured against a reference cell
Get Price
Oxidation of pyrite releases toxic metals and metalloids such as arsenic a poisonous element Coal veins often contain pyrite with arsenic Coal veins often contain pyrite with arsenic The mineral poses a severe health problem for millions of people such as those in the Guizhou province in China
Get Price
The sulfur content of coal treated in accordance with this method can be reduced by subjecting the treated coal to a low strength magnetic field for moving at least 50% by weight of the pyrite from the coal although a smaller fraction about 5 to 25% of the pyrite is actually converted to magnetite Cited by 2
Get Price
Sample No 3 was selected from the material donated by the Sulphur Mining and Railroad Co In addition to a large amount of pyrite it contained a noticeable amount of magnetite biotite muscovite quartz and small amounts of chalcopyrite and sphalerite its analysis was as follows Iron per cent sulfur per cent copper
Get Price
Composed of iron and sulphur pyrite can contaminate ground water and streams via tailings waste from mines Oxidation of pyrite releases toxic metals and metalloids such as arsenic a poisonous element Iron ores such as Pyrite Hematite Magnetite and Goethite should not be cleansed in water for long periods Why
Get Price
A column experiment filled with a pyrite rich sludge with artificial irrigation leached acid drainages pH approx 2 containing high concentrations of sulphate iron and other metals However non saturated column experiments filled with pyritic rich sludge and fly ash drained leachates characterized by alkaline pH pH up to 10 low sulphate
Get Price
Made available by Department of Energy Office of Scientific and Technical Information
Get Price
This is because while pyrite can be tumbled and polished even turned into beads it is very hard to get a smooth finish Tumbling and polishing can bring out the metallic shine but most pieces will be pockmarked giving them a look of imperfection such as Pyrite Hematite Magnetite and Goethite should not be cleansed in water for long
Get Price
When bituminous coal is heated in an inert atmosphere He containing small amounts of oxygen at 393 455 C pyrite FeS2 in coal is partially converted to magnetite Fe304 The maximum amount of Fe304 formed during the time of heating corresponds to 5 20% of the total pyrite present depending on the coal sample The magnetite forms as an outer crust on the pyrite grains
Get Price
Oxidation of pyrite can result in damage to pavement foundations and floors In parts of the country where pyrite is commonly found construction sites should be tested to detect the presence of pyritic materials If pyrite is detected the site can be rejected or the problem materials can be excavated and replaced with quality fill
Get Price
The acidification process of coal mine water is not caused by the process of pyrite oxidation rather it occurs through the process of iron conversion to the Fe OH 3 complex after the pyrite oxidation Therefore to prevent the formation of acidic mine water the geological and hydrogeological conditions of the site can be combined to
Get Price
Oxidation of pyrite in coal to magnetite ScienceDirect When bituminous coal is heated in an inert atmosphere He containing small amounts of oxygen at 393 455 °C pyrite FeS 2 in coal is partially converted to magnetite Fe 3 0 4 The maximum amount of Fe 3 0 4 formed during the time of heating corresponds to 5 20% of the total pyrite present depending on the coal sample
Get Price
On the other hand the latter including lead zinc veins with or without pyrrhotite is a region bounded by the assemblages alabandite rhodochrosite graphite carbon di oxide pyrite pyrrhotite pyrite magnetite and oldahmite anhydrite Among them the mineral assemblage pyrite bornite chalcopyrite is characteristic of the Kuroko deposits
Get Price
Sam Houston State University 1996 19993 years Huntsville Texas USA Guiding in house research scientists having multi disciplinary backgrounds and coordinating the major research findings
Get Price
In Our Society The Economic Importance of Pyrite Despite being a common iron rich mineral pyrite is rarely mined for its own sake and most of our iron is produced from magnetite and hematite deposits Those iron oxide minerals occur in larger concentrations and volumes than pyrite so they are a more economical iron source
Get Price
RESULTS At the ridgelines of the shale watershed most pyrite oxidation occurs within a 1 m thick reaction zone ∼16 m below land surface just above the depth of water table fluctuation This is the reaction front at the borehole scale Only limited oxidation occurs in halos around a few fractures at deeper depths
Get Price
Oxidation of pyrite leads to coating of cenospheres by condensed magnetite and the emission of sulphur dioxide in the flue gases Type Research Article Chemical composition and size of particles in emissions of a coal fired power plant with flue gas desulfurization Journal of Aerosol Science Vol 73 Issue p 14
Get Price
To test the effect of pyrite composition and environmental parameters on the rate and extent of pyrite oxidation in coal splits of five bituminous coal samples having differing amounts of pyrite and extents of As substitution in the pyrite were exposed to a range of simulated weathering conditions over a period of 17 months
Get Price
This model is based on spherical diffusion and was first applied to the study of the oxidation of magnetite in air by Sidhu et al 20 This model was subsequently applied to magnetite oxidation under a controlled atmosphere by Bourgeois et al 16 and has also been used to assess the aqueous oxidation of magnetite at low temperatures ≤80 °C
Get Price