Fine-grained pyrite mainly occurs in the form of framboïdal pyrite, disseminated pyrite, and monomer pyrite with a size of 0.69-33.94 μm in the middlings and cleaned coal.

in the mined-out areas will be greatly shortened. erefore, the research on the mechanism of pyrite-catalyzed coal spontaneous combustion is particularly important. e oxidation forms of pyrite in ...

Abstract and Figures. During transportation and stockpiling, coal is in contact with air for periods of time that may exceed 6 months. During this time, reaction with oxygen in the presence of ...

Electrochemical methods including anodic dissolution have many applications in the mining industry as well as the oil and gas industry. The use of redox potential has been shown to aid pyrite oxidation which has its application in acid mine drainage 13.A recent study reported that the oxidation of pyrite is important in black …

Pyrite has a significant effect on the spontaneous combustion of coal. The presence of pyrite can change the propensity of coal towards spontaneous combustion. The influences of various pyrite contents on the parameters of spontaneous combustion, such as index gases, temperature and …

Sulphides, mainly pyrite, are very common minerals in source rocks for oil and natural gas. Pyrite thermal transformation is very complex process, depending on many factors affecting the decomposition reactions. Thermal decomposition of pyrite contained in bulk rock is even more complex due to the possible interactions with organic matter ...

The evaluation of the effect of temperature was conducted on pyrite dissolution in 3 M nitric acid, where the temperature varied from 25 to 85 °C. Temperature vastly influences the process because it affects the rate of the leaching process, i.e., both the diffusion and the reaction rate .

In recent years, the HyPy process has been useful in reducing the sulfur content of liquid fuel from coal conversion and yielding low-sulfur semi-coke or char. …

Under the oxidative roasting process, pyrite, as a major mineral in sulfidic mine tailings, can transform to iron oxides. Generated iron oxides, if exhibiting enough magnetic properties, can be recovered via magnetic separation resulting in partial mine tailings valorization. However, due to the presence of various minerals and sintering …

reactive and non-reactive pyrite and to quantify the effect of reactive pyrite on the self-heating process. Coal Samples Analytical details of the high volatile bituminous coal samples used in this study are contained in Table 1. Coals C and D are from the same seam and location at an underground mine with a known

The risk of flooding and the presence of pyrite in the coal body are both common in underground coal mines, and many pyrite-rich working faces have severe watering problems at the same time [34], [35]. However, there are still few studies on the mutual effect of water immersion and pyrite on the spontaneous combustion …

Separation technologies to remove gangue minerals and impurities in coal are based on mineral processing technologies and a summary of the largest mines in top 5 countries of coal production including production, reserves, coal types, impurities, mining methods, and coal cleaning processes were shown in Table 3. In some coal mines …

Flotation desulfurization experiments showed that the sum of pyrite content in the cleaned coal and middlings gradually became significantly higher in coal particles …

The occurrence of spontaneous combustion is not limited to coal but the phenomenon is known to take place in a number of coal-shale, pyritic black shale and coal refuse (Kim and Chaiken 1990; Onifade and Genc 2018e, f, g; Restuccia et al. 2017; Rumball et al. 1986).The principles that control spontaneous combustion are similar in all …

process of spontaneous combustion. The coal sample with a pyrite content of 5 % has the largest CO release rate and oxygen adsorption as well. However, the coal sample with a pyrite content of 7 % ...

Other problems that may arise from the use of coal are not necessarily harmful to the environment or human health, but affect the use and efficiency of coal-burning equipment. For example, certain constituents in coal may cause severe erosion and corrosion of, or the buildup of mineral deposits on, furnace and boiler parts.

1. Introduction Pyrolysis is an effective and mild coal conversion process. The poly-generation technology based on coal pyrolysis can produce many valuable products such as high-calorific pyrolysis gas, upgraded coal tar, and clean solid fuel char or coke, which will realize multi-level efficient utilization of coal resources. 1,2 The products of coal …

In this work, an analysis of impurities in the pyrite of southern Santa Catarina (Brazil), including organic matter, sulfates, iron oxides, calcite, clay and sandstone, …

Formation Process. Pyrite can be discovered in a variety of geological formations, such as sedimentary deposits, hydrothermal veins, and metamorphic rocks. It can also be found as an exciting accessory mineral in igneous rocks, as long as iron and sulfur are present. Pyrite is a mineral that occurs in a variety of forms.

Northumberland coal samples taken from the Shotton site contain three types of pyrite: (1) rare framboidal disseminated pyrite, typically <5 μm in diameter (Fig. 3 a), (2) cubic disseminated pyrite, up to 2 mm in length (Fig. 3 b), and (3) pyrite concentrated in cleats, up to 2 mm wide (i.e. fractures, veins and veinlets that resulted from ...

The electrochemical oxidation process of pyrite promotes the enhancement of coal polarization and promotes the development of reactive …

The effect of dust on the efficiency of electrostatic separation of pyrite from a closely sized coal is shown in table 3 and table 4 and the accompanying graphs (figs. 5-6). Figure 5 shows the results with a low-sulfur dust. Separation efficiency is not significantly decreased until more than 10 pct dust is added.

Pyrite was once a source of sulfur and sulfuric acid, but today most sulfur is obtained as a byproduct of natural gas and crude oil processing. Today pyrite is sometimes sold as a novelty item or …

Introduction. Pyrite (FeS 2) is a naturally occurring material that can be found in concentrated form in nature and also as impurities in coal and many other minerals.The wide occurrence of pyrite in different minerals and coals makes it one of the main sources of SO 2 emission from various industrial activities, such as the metallurgical industry, power …

To assess the thermal transformation process of common sulfide minerals in a nitrogen atmosphere, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and thermogravimetric mass spectrometry are employed to define the influence of the pyrrhotite content in pyrite-pyrrhotite mixtures (mixed minerals). The results …

The transformation behavior of pyrite (FeS2) in the blast furnace process is critical to control the formation and emission of gaseous sulfides in the top gas of ironmaking but has seldom been explored. In present work, the pyrolysis of pyrite from 200 to 900 °C under a CO–H2 atmosphere was investigated by thermal-gravimetric and mass …

In order to uncover the effect of pyrite on the tendency of coal to spontaneously combust, thermal analysis was carried out to characterize the reaction process of coal with different pyrite contents at four heating rates of 5, 10, 15, and 20 K min −1 in air flow from 25 to 900 °C. The Flynn-Wall-Ozawa method was applied to …

how does pyrite affect the utilisation and processing of ... Pyrite – Wikipedia, the free encyclopedia … primarily used to refer to pyrite found in coal.Pyrite is the most … environment: in nature it is always in the process of being created or being destroyed. Iron pyrite … » Free Online Chat USGS Fact Sheet 073-02: Coal Extraction

Pyrite oxidizes quickly and is a major source of sulfur to the ocean, but it is also a proxy for the oxygen content historically in Earth's atmosphere. Gu et al. conducted a set of detailed observations of the pyrite oxidation process in a shale unit. The authors found that erosion tied to fracturing is just as important as the oxygen content ...

The pyrite from coal mining in southern Santa Catarina (Brazil) is rich in other ferrous compounds, sulfates and oxides according to the infrared spectra. The high silicon content, together with elements such as aluminum, calcium, potassium, magnesium, manganese and sodium, suggest that the material has a sandy and clay fraction.