Mineral matter in coals and their reactions during coking

Grigore, Mihaela; Sakurovs, Richard; French, David; Sahajwalla, Veena

doi:10.1016/j.coal.2008.08.013

Cited by 43 publications

(32 citation statements)

References 16 publications

(26 reference statements)

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“…Many problems are arises due to the large utilization of high ash coal includes more amount of ash disposal, fouling of economizers, corrosion of boiler walls, and high amount of fly ash emission. It may also be a source of abrasion, corrosion, stickiness, fouling, or pollute to the environment by the generation of solids or gaseous pollutants during coal handling and use [16][17][18].…”

Section: Mineral Matters In Coalmentioning

confidence: 99%

A review of chemical leaching of coal by acid and alkali solution

Behera¹,

Kumari²,

Meikap³

2018

J Min & Metal A Mining

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Low rank or low-grade (LRC or LGC) coals are most abundant distribute around the several regions in the world. The contribution of low-rank coal is a significant role in the energy sectors and chemical feedstock to the industries. The hard coal reserves are gradually depleting, and the mining operation at deeper coal seam with greater difficulties as well as the cost of exploration is so high, which has a significant issue for plant economics. Therefore, the low-grade coal can be used as an alternative energy source to minimize these problems. Low-rank coals are usually associated with high mineral matter and moisture content, which exerts substantial impacts on their consumption including pyrolysis, liquefaction, gasification and combustion process. In order to understand the essential treatment of coal for efficient removal of mineral matters and improve coal properties by beneficiation techniques are crucial to developing advanced technologies. The present article provides a comprehensive overview of the various processes concerning demineralization of coal by chemical beneficiation technique. It has been found from the study; the degree of demineralization was greater in chemical beneficiation compared to physical beneficiation. It is because the chemical reagents are attacked to the interior of coal which removes the inorganic materials and finely dispersed minerals from the coal matrix. The chemical methods have separated all types of minerals from the coal matrix. However, the separation of minerals by the physical method depends on the mineral properties. Chemical beneficiation is an appropriate method to reduce both organic and inorganic mineral constituents from the LGC by leaching method. The chemical reagents are diffusing to the interior of coal matrix through the pores and subsequently dissolute the minerals. Throughout the study challenges, the chemical cleaning of low-grade coal has been efficient techniques for reducing the minerals to a minimum level that can be upgraded to high rank coal.

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Section: Mineral Matters In Coalmentioning

confidence: 99%

A review of chemical leaching of coal by acid and alkali solution

Behera¹,

Kumari²,

Meikap³

2018

J Min & Metal A Mining

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“…Mineral matter present in coal may occur as minerals, mineraloids and as organically-associated inorganic elements [1], which may interact in different ways during combustion [2][3][4][5][6][7], coking [8] and gasification processes [9][10][11][12][13]. A distinction is sometimes made between "included minerals" and "excluded minerals", especially in pulverized fuel combustion.…”

Section: Introductionmentioning

confidence: 99%

Behaviour of coal mineral matter in sintering and slagging of ash during the gasification process

Matjie

French

Ward

et al. 2011

Fuel Processing Technology

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The mineral matter in typical feed coals used in South African gasification processes and the ash derived from gasifying such coals have been investigated using a variety of mineralogical, chemical and electron microscope techniques. The mineral matter in the feed coals consists mainly of kaolinite, with minor proportions of quartz, illite, dolomite, calcite and pyrite plus traces of rutile and phosphate minerals. The calcite and dolomite occur in veins within the vitrinite macerals, and are concentrated in the floats fraction after density separation. Some Ca and Ti also appear to be present as inorganic elements associated with the organic matter. Electron microscope studies show that the gasification ash is typically made up of partly altered fragments of non-coal rock, bonded together by a slag-like material containing anorthite and mullite crystals and iron oxide particles, with interstitial vesicular glass of calcic to iron-rich composition. Ash formation and characteristics thus appear to be controlled by reactions at the particle scale, allowing the different types of particles within the feed coal to interact with each other in a manner controlled mainly by the modes of mineral occurrence. Integration of such techniques provides an improved basis for evaluating ash-forming processes, based on quantitative phase identification, bulk and particle chemistry, and the geometric forms in which the different phases occur.

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“…temperature, oxidation/reduction), the mode(s) of mineral or element occurrence within the coal, and the opportunities for and duration of contact between the various phases in the utilization system (e.g. Bryers, 1996;Grigore et al, 2008;Matjie et al, 2011Matjie et al, , 2012aMatjie et al, , 2012bCreelman et al, 2013).…”

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confidence: 99%