Abstract: A method of recovery of organic solvents required in the refining of coal comprising: mixing solvent, co-solvent and coal to form a slurry; thermally treating the slurry under pressure and high temperature to form a coal-extract; passing the coal-extract through a membrane under high pressure in an ultra filtration unit to achieve recovery of a major part of the solvent; contacting the remaining thick clarified liquid from the membrane with water to obtain precipitated coal in a slurry with a mixture of water and organic solvent; feeding the slurry to a filter to get clean coal of very low ash content as a residue and a mixture of water and organic solvent as a filtrate; distilling the filtrate to separate the balance of the organic solvent from the water. The application of a membrane for filtration minimizes the heat requirement to establish economy.

Abstract: This invention relates to a cyclone for dense medium separation that includes an inverted conical shaped cyclone body which provides an interior space having an inner wall surface a vortex finder including a lower end that extends longitudinally into an upper region of the interior space of the cyclone body an overflow outlet associated with an upper end of the vortex finder a feed inlet that is in fluid communication with the upper region of the interior space of the cyclone body an outlet associated with a lower region of the interior space and the inner wall surface of the interior space curves inwardly and downwardly from the upper region curves inwardly and downwardly from the upper region of the interior space to the lower region of the interior space.

Abstract: A process to produce low ash clean coal from high ash coal with substantially complete solvent recovery, the process including: forming a slurry of coal fines in a N-Methyl-2-pyrrolidone (NMP) and Ethylenediamine (EDA) solution; maintaining said slurry in a reactor at a temperature range of 100° C. to 240° C. and a pressure range of 1 to 4 gauge (kg/cm2) for a period of about 15 minutes to 4 hours; separating the produced sample withdrawn from the reactor, one part being a filtrate and the other a reject; feeding the filtrate into an evaporator to recover 80-85% solvent; precipitating the concentrated filtrate material in an anti-solvent tank to separate coal from solvent; separating the coal by filtration, said separated coal having a reduced ash content; feeding the anti-solvent and solvent mixture into a distillation column to separate remaining solvent from the anti-solvent for reuse in the process.

Abstract: A process to produce low ash clean coal from high ash coal with substantially complete solvent recovery, the process including: forming a slurry of coal fines in a N-Methyl-2-pyrrolidone (NMP) and Ethylenediamine (EDA) solution; maintaining said slurry in a reactor at a temperature range of 100° C. to 240° C. and a pressure range of 1 to 4 gauge (kg/cm2) for a period of about 15 minutes to 4 hours; separating the produced sample withdrawn from the reactor, one part being a filtrate and the other a reject; feeding the filtrate into an evaporator to recover 80-85% solvent; precipitating the concentrated filtrate material in an anti-solvent tank to separate coal from solvent; separating the coal by filtration, said separated coal having a reduced ash content; feeding the anti-solvent and solvent mixture into a distillation column to separate remaining solvent from the anti-solvent for reuse in the process.

Abstract: A beneficiation process to produce low ash clean coal from high ash coals, including: preparing a coal slurry from fine coal and water and discharging it to a first reactor; preparing an alkali solution and discharging it to a first reactor; carrying-out a leaching reaction inside the first reactor; transferring the reaction mixture to a second reactor for filtration and washing to produce a filter cake; preparing a diluted acid solution and delivering it to a second reactor; preparing a diluted alkali solution and delivering it to a second reactor; feeding a coal slurry prepared from the filter cake into the second reactor for washing and transferring to a second filtration unit; transferring the product after filtration to a third reactor; carrying-out different leaching reaction sequences in the first, second, and third reactors; and transferring to a fifth tank the treated coal filter cake for drying.

Abstract: An improved frothing agent adaptable to froth flotation process to enhance coal selectivity for separation and efficiency of the froth flotation process comprises: A blended mixture of Ketone (2,6-Dimethyl-4-Heptanone) 85-89% (Wt %) Ester molecule(Tetrahydrofurfuryl acetate) 10-12% (Wt %) Epoxide conditioner (1,2-Epoxydodecane) 0.25-0.30% (Wt %) Water 4.75-5.

Abstract: An improved organo-refining process to produce low ash clean coal from high ash coal, comprising: mixing coal, solvent and a co-solvent to produce a slurry; feeding the slurry to a reactor by pumping; extracting a coal-solvent mixture from the reactor; feeding the extracted mixture to a flasher unit; recovering about 30% of the solvent from the flashing unit; feeding the remaining heavy material to an evaporator; extracting about 60% of solvent from the evaporator; discharging the residue from the evaporator to a precipitator having water which produces a coal slurry; filtering the slurry in a rotary drum; collecting the super clean coal as a residue and feeding the filtrate into a distillation unit; and separating the water and the organic material in the filtrate to recover at least 7 to 8% of the remaining solvent.

Abstract: A method of recovery of organic solvents required in the refining of coal comprising: mixing solvent, co-solvent and coal to form a slurry; thermally treating the slurry under pressure and high temperature to form a coal-extract; passing the coal-extract through a membrane under high pressure in an ultra filtration unit to achieve recovery of a major part of the solvent; contacting the remaining thick clarified liquid from the membrane with water to obtain precipitated coal in a slurry with a mixture of water and organic solvent; feeding the slurry to a filter to get clean coal of very low ash content as a residue and a mixture of water and organic solvent as a filtrate; distilling the filtrate to separate the balance of the organic solvent from the water. The application of a membrane for filtration minimizes the heat requirement to establish economy.

Abstract: This invention relates to a cyclone for dense medium separation that includes an inverted conical shaped cyclone body which provides an interior space having an inner wall surface a vortex finder including a lower end that extends longitudinally into an upper region of the interior space of the cyclone body an overflow outlet associated with an upper end of the vortex finder a feed inlet that is in fluid communication with the upper region of the interior space of the cyclone body an outlet associated with a lower region of the interior space and the inner wall surface of the interior space curves inwardly and downwardly from the upper region curves inwardly and downwardly from the upper region of the interior space to the lower region of the interior space.

Abstract: An improved organo-refining process to produce low ash clean coal from high ash coal, comprising: mixing coal, solvent and a co-solvent to produce a slurry; feeding the slurry to a reactor by pumping; extracting a coal-solvent mixture from the reactor; feeding the extracted mixture to a flasher unit; recovering about 30% of the solvent from the flashing unit; feeding the remaining heavy material to an evaporator; extracting about 60% of solvent from the evaporator; discharging the residue from the evaporator to a precipitator having water which produces a coal slurry; filtering the slurry in a rotary drum; collecting the super clean coal as a residue and feeding the filtrate into a distillation unit; and separating the water and the organic material in the filtrate to recover at least 7 to 8% of the remaining solvent.

Abstract: An improved frothing agent adaptable to froth flotation process to enhance coal selectivity for separation and efficiency of the forth flotation process comprises:- A blended mixture of Ketone (2,6 Dimethl-4-Heptanone) 85-89% (Wr %) Ester molecule(Tetrahydrofurfuryl acetate) 10-12% (Wt %) Epoxide conditioner (1,2-Epoxydodecane) 0.25-0.30% (Wt %) Water 4.75-5.