Pilot scale demineralization study on coal flotation tailings and optimization of the operational parameters with modeling

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

doi:10.1016/j.minpro.2015.11.004

Cited by 12 publications

(3 citation statements)

References 18 publications

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“…Work can be extended in this direction in the future. The use of Box-Beign experimental design for chemical demineralisation using NaOH-HCl of a low ash coal floatation tailings has also been studied by Suresh et al (2015) where the optimization of the process conditions such as coal particle size, reaction time, reagent concentration %, reaction temperature have been studied and the STATISTICA software has been used to carry out regression analysis to develop the model. The most optimized conditions were found to be 160°C as reaction temperature, 60.6 min as reaction time and 17.6% reagent concentration where the resulting product was found to have least ash content.…”

Section: Alkali-acid Leaching Of Coalsmentioning

confidence: 99%

Advances in the chemical leaching (inorgano-leaching), bio-leaching and desulphurisation of coals

Dhawan

Sharma

2019

Int J Coal Sci Technol

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Coal still remains an important source of power generation world over. Along with its usage, comes unwanted generation of noxious gas emissions, toxic metal releases into wastewater and other pollutants which ultimately lead to environmental concerns. So cleaning of coal through physical or chemical processes becomes utmost important. There are several coals which cannot be cleaned by physical beneficiation techniques to produce low ash cleaner coals. Such coals can be cleaned only through chemical cleaning techniques. The present paper reviews the chemical demineralisation and desulphurisation of coals over the years using various inorganic and organic acids, alkalis, oxidants, leachants and various acids and alkali-acid combinations to reduce the ash and sulphur contents in coals. As high as 90% demineralisation and desulfurization could be achieved with the use of these cheap inorganic acids as compared to the expensive solvents used for solvent extraction processes, a parallel approach of cleaning and refining coals.

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Section: Alkali-acid Leaching Of Coalsmentioning

confidence: 99%

Advances in the chemical leaching (inorgano-leaching), bio-leaching and desulphurisation of coals

Dhawan

Sharma

2019

Int J Coal Sci Technol

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“…According to the nature of Indian coal (drift origin) both low ash and high yield cannot be attained at a time through physical beneficiation route. The low yield is mainly contributed by poor liberation (Suresh, 2015). Most of washeries techniques depends on liberation characteristics and surface properties.…”

Section: Figure 1 Coal Beneficiation Technique Flow Chartmentioning

confidence: 99%

Recovery of Coal Values from Middling and Rejects by Froth Flotation and Mozley Mineral Separation

Mdoe

Anupam²

2021

SET

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The recovery of coals values from Middling and Rejects carries out by using Froth flotation and Mozley Mineral Separation. The middling and rejects are the waste products from gravity beneficiation process, it has been noted that most of washery plants are selling this product at low cost because they have less values.The independent variables selected for Mozley Mineral Separator and their ranges were indicated in the parentheses as follow, water flow rates (400, 600, 800ml/s), amplitude (1.25, 1.5, 1.75inch) and collection time (30, 40, 60 s) while the independent variables for froth flotation were; Pulp density (10, 12.5, 15 %), collector dosage (39.3, 44.4, 49.5 g/t) and frother dosage (61.8, 65.3, 68.8 g/t). The number of experimental runs and regression equation determined by using Design Expert softwareThe d80 for middling and rejects samples were 10.5mm and 12.89mm respectively. The ash contents for the middling sample treated by froth flotation decrease from 37% to 15.85% at the reagent concentration of 49.5g/t collector, 65.3g/t frother and pulp density of 10%. The froth flotation results of middling sample shown to have a great reduction of ash contents. The overall optimum middling recovery and yield for washery grade I and II attain at reagent concentration and pulp density of 47.703g/t, 68.568g/t and 13.2% for collector, frother and pulp density respectively. The feed of reject coal was 71% and the ash contents reduced to 28.87% with the recovery of 0.85%. The analysis through Mozley mineral separator did not show significant changes in the reduction of ash from both middling and rejects. The ash contents achieved were above the scope of the studies for recovering of coal values. The experiments for middling and reject by froth flotation and Mozley mineral separator may be carried out by varying other parameters as well as the type of methods.

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“…Chemical beneficiation requires fine coal (less than 500 micron), so that the active surface for reagent to react will be more, but handling of fine coal requires more water/aqueous reagents to avoid frequent choking in the pipelines. Leaching process demonstrated till pilot scale (Dash et al, 2013(Dash et al, , 2014(Dash et al, , 2015a(Dash et al, , 2015bSuresh et al, 2015, Lingam et al, 2016Sriramoju et al, 2016aSriramoju et al, , 2016b, but the economics of the process purely depends on maximum recovery of reagents (alkali and acid) and regeneration of used chemicals. Steel and Patrick (2004) studied the leaching kinetics with hydrofluoric acid and the regeneration of the spent acid is carried out by distillation in nitric acid stream followed by the pyrohydrolysis of solids above 500°C temperature.…”

Section: Introductionmentioning

confidence: 99%

Study on regeneration of spent hydrochloric acid in chemical coal leaching process

Sriramoju

Dash

2019

IJEWM

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For Indian coals, chemical leaching process has better advantage over the conventional physical cleaning techniques due to its drift origin. Coal leaching is a two-stage process where alkali and acid leaching cycles are used, where most of the ash constituents are accumulated in the spent acid and hence purification of spent acid containing silica, alumina, iron, calcium and magnesium is of great importance. Four different methods namely adsorption using activated carbon, ion exchange with anion exchange resin, pyrohydrolysis and stage-wise neutralisation are studied. Results with adsorption and ion exchange techniques are poor and a maximum of 50% removal is observed. Results indicate that, pyrohydrolysis shows better performance with > 99% pure hydrochloric acid as product but it is energy intensive. Stage-wise neutralisation technique is promising for dilute acid, where silica is precipitated by digestion and it produces magnesium oxide and calcium salt with 86.7% and 93.86% purity respectively.

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Pilot scale demineralization study on coal flotation tailings and optimization of the operational parameters with modeling

Cited by 12 publications

References 18 publications

Advances in the chemical leaching (inorgano-leaching), bio-leaching and desulphurisation of coals

Advances in the chemical leaching (inorgano-leaching), bio-leaching and desulphurisation of coals

Recovery of Coal Values from Middling and Rejects by Froth Flotation and Mozley Mineral Separation

Study on regeneration of spent hydrochloric acid in chemical coal leaching process

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