Mechanism of a Coal Chemical-Leaching Process and Recovery of Spent Chemicals: A Pilot-Scale Study

Sriramoju, Santosh Kumar; Suresh, A.; Lingam, Ravi Kumar; Dash, Pratik Swarup

doi:10.1080/19392699.2016.1179637

Cited by 18 publications

(6 citation statements)

References 12 publications

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“…DM-Demineralization, DS-Desulfurization, T-Temperature (°C), P-Pressure, t-Time, µm-Micrometer Figure 2. Mechanism of gel formation during leaching process [48] The following reactions (10) and (11) indicate the part of pyrite and organic sulfur can remove during alkali treatment.…”

Section: Alkali Leachingmentioning

confidence: 99%

“…The several literature studies revealed the great potential for chemical cleaning of coals, with better ash removal was obtained from the coal. Chemical cleaning method has not widely employed on a commercial scale due to huge cost related to the requirements of chemicals and the need for dewatering of the post-demineralization and regeneration of reagents from spent solution [8][9][10]. It can be seen from literature only a few studies about the regeneration of chemical reagents from the spent solution by adding a suitable chemical reagent.…”

Section: Introductionmentioning

confidence: 99%

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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: Alkali Leachingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Behera¹,

Kumari²,

Meikap³

2018

J Min & Metal A Mining

View full text Add to dashboard Cite

show abstract

“…Chemical leaching process usually achieved remove all types of minerals from the coal compared to physical treatment method. Although, chemical cleaning method has not been widely employed on a commercial scale due to huge cost related to the requirement of chemical and need for dewatering and regeneration of reagents from spent solution (Wu and Steel 2007;Waugh and Bowling 1984;Ryberg et al 2015;Sriramoju et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Demineralization mechanism and influence of parameters on high ash Indian coal by chemical leaching of acid and alkali solution

Behera

Chakraborty

Meikap

2018

Int J Coal Sci Technol

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The current research was investigated the mechanism of coal demineralization and the effect of leaching parameters on high ash coal and study the characterization of pre and post-treated coal. The two high ash Indian coal selected from Mahanadi Coalfield Limited, Odisha, pulverized to 375, 230 and 180 lm particle size were undergone simultaneous acid and alkali treatment at a different concentration, temperature and time. The percent demineralization was increased with decrease the size of the particle and rises with leaching parameters. The investigation suggested 180 lm particle size offers efficient demineralization for both coals at 30% NaOH and 30% H 2 SO 4 concentration. The alkali leaching leads to obtaining the demineralization 46% and 42% whereas acid treatment resulted in 34% and 32% of the original coal samples. The extent of demineralization was improved the calorific value of coal. Besides, the degree of demineralization was proved from the FTIR, XRF and FESEM-EDX analysis results. FTIR analysis result showed that the peak intensity of mineral band decreased by the leaching effect and the degree of demineralization was significantly obtained to large extent by the X-ray Fluorescence spectrometer; which elucidates major minerals removed from coal by the leaching effect of acid and alkali solution.

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“…), that is, to remove the ash and sulfur value at the desired rate (Yagmur et al, 2005;Ayhan et al,2011;Ceylan and Kucuk, 2004). Acid leaching techniques are used as an alternative to the conventional cleaning processes of coals (Behera et al, 2018a;Sriramoju et al 2017;Sriramoju et al 2020). There are many studies on reducing coal ash using acid leaching methods for example with caustic acids (Chriswell et al 1989;Sharma and Gihar 1991;Hacifazlioğlu, H., Uçkan, D., 2014;Dash et al, 2013;2015a;2015b).…”

Section: Introductionmentioning

confidence: 99%