Coal recovery processes utilizing agglomeration and density differential separations

Claim 2

A process for recovering coal from a particulate composite in which said coal is associated with mineral matter, said process comprising the steps of: agitating the particles of said composite in a slurry in an aqueous carrier containing an agglomeration promoting additive with respect to which the coal is hydrophobic to effect a separation of the coal particles from the mineral matter, a coalescence of said particles into agglomerates, and the ejection of mineral matter into dispersion in said aqueous carrier; recovering said agglomerates from said aqueous carrier; effecting a resolution of said agglomerates into the particles into which they are composed; and subjecting said particles to density differential separation in a body of parting liquid, whereby those particles which have a relatively high concentration of mineral matter will migrate to the bottom of said body of parting liquid and those particles contain a lower proportion of mineral matter and a high proportion of coal will rise to the top of said body of parting liquid; and thereafter separately recovering the floats and the sinks from said body of parting liquid.

Claim 3

A process as defined in claim 1 in which said resolution of agglomerates into particles is effected and said agglomeration promoting additive separated therefrom by contacting said agglomeration promoting additive with a liquid in which said additive is soluble.

Claim 4

A process as defined in claim 2 in which the agglomeration promoting additive comprises a petroleum distillate or solvent; a nitrobenzene; a kerosene; a lubricating, fuel, or residual oil; or a chlorinated biphenyl.

Claim 5

A process as defined in claim 3 in which, after said product coal agglomerates are contacted with said solvent, the solvent and agglomeration promoting additive solution is mechanically separated from the solids into which the agglomerates are resolved, said solution thereafter being resolved into its constituents and said constituents being recycled.

Claim 6

A process as defined in any of the preceding claims 2, 3, or 4 in which said solvent is a halogenated C 1 or C 2 hydrocarbon which is immiscible with water and which has from two to six halogen atoms.

Claim 7

A process as defined in claim 1 in which the resolution of said agglomerates into particles and the recovery of the agglomeration promoting additive therefrom is carried out in said body of parting liquid.

Claim 8

A process as defined in claim 1 in which the resolution of said agglomerates into particles and the recovery of the agglomeration promoting additive therefrom is carried out prior to the density differential separation of said particles.

Claim 9

A process as defined in claim 1 in which said parting liquid is a halogenated hydrocarbon that is immiscible with water and has a specific gravity in the range of 1.2 to 2.2 and from two to six halogen atoms.

Claim 10

A process as defined in claim 1 in which said composite is comminuted while in said aqueous carrier to promote the separation of the coal from the mineral matter associated therewith and the coalescence of said coal into product coal agglomerates.

Claim 11

A process as defined in claim 1 in which calcium oxide is added to said slurry concomitantly with the agglomeration of the coal particles thereof to promote the rejection of pyritic sulfur from the product coal agglomerates into dispersion in said aqueous carrier.

Claim 12

A process as defined in claim 1 which includes the step of, prior to effecting said density differential separation, contacting said agglomerates with a solvent in which said agglomeration promoting additive is soluble to thereby effect a separation of said additive from said agglomerates and make it available for reuse in the process.

Claim 13

A process as defined in claim 1 in which the agglomeration promoting additive comprises at least one fluorocarbon selected from the group consisting of: dichlorofluoromethane trichlorofluoromethane 1,1,2,2-tetrachloro-1,2-difluoroethane 1,1,2-trichloro-1,2,2-trifluoroethane 1,1-dichloro-1,2,2,2-tetrafluoroethane 1-chloro-2,2,2-trifluoroethane 1,1-dichloro-2,2,2-trifluoroethane 1-chloro-2-fluoroethane and mixtures of the foregoing.

Claim 14

A process for recovering coal from a particulate composite in which said coal is associated with mineral matter, said process comprising the steps of: agitating the particles of said composite in slurry in an aqueous carrier containing an agglomeration promoting additive with respect to which the coal is hydrophobic to effect a separation of the coal particles from the mineral matter, a coalescence of said particles into agglomerates, and the ejection of mineral matter into dispersion in said aqueous carrier; recovering said agglomerates from said aqueous carrier; agitating said agglomerates in slurry with a surface active agent and with a halogenated C 1 or C 2 hydrocarbon in amounts and for a time sufficient to effect a resolution of said agglomerates into the particles into which they are composed, a transfer of moisture to those particles having a relatively high mineral matter content, an agglomeration of those particles, and the envelopment of those particles having a lower mineral matter content and a relatively high coal content with the surface active agent; and subsequently subjecting said particles to density differential separation in a body of a parting liquid comprising a halogenated C 1 or C.sub. 2 hydrocarbon having a specific gravity intermediate those of the particles having a relatively high coal content and the agglomerates of particles with a relatively high mineral content, whereby said agglomerates will sink to the bottom of said body of parting liquid and those particles which contain a lower proportion of mineral matter and a high proportion of coal will disperse in and migrate to the top of said body of parting liquid; and thereafter separately recovering the floats and the sinks from said body of parting liquid.

Claim 15

A process for recovering coal from a particulate composite in which said coal is associated with mineral matter, said process comprising the steps of: agitating the particles of said composite in slurry in an aqueous carrier containing an agglomeration promoting additive with respect to which the coal is hydrophobic to effect a separation of the coal particles from the mineral matter, a coalescence of said particles into agglomerates, and the ejection of mineral matter into dispersion in said aqueous carrier; recovering said agglomerates from said aqueous carrier; agitating said agglomerates in slurry with a surface active agent and with a halogenated C 1 or C 2 hydrocarbon in amounts and for a time sufficient to effect a resolution of said agglomerates into the particles into which they are composed, a transfer of moisture to those particles having a relatively high mineral matter content, an agglomeration of those particles, and the envelopment of those particles having a lower mineral matter content and a relatively high coal content with the surface active agent; and subsequently subjecting said particles to density differential separation in a body of a parting liquid comprising a halogenated C 1 or C.sub. 2 hydrocarbon having a specific gravity intermediate those of the particles having a relatively high coal content and the agglomerates of particles with a relatively high mineral content, whereby said agglomerates will sink to the bottom of said body of parting liquid and those particles which contain a lower proportion of mineral matter and a high proportion of coal will disperse in and migrate to the top of said body of parting liquid; and thereafter separately recovering the floats and the sinks from said body of parting liquid.

Claim 16

A process as defined in claim 13 which includes the steps of removing agglomeration promoting additive/parting liquid solution formed in effecting the resolution of those agglomerates containing said additive from the separator in which the density differential separation is carried out; resolving the solution into its constituents; and recycling said constituents.

Claim 17

A process for recovering coal from a particulate composite in which said coal is associated with mineral matter, said process comprising the steps of: agitating the particles of said composite in slurry in an aqueous carrier containing an agglomeration promoting additive with respect to which the coal is hydrophobic to effect a separation of the coal particles from the mineral matter, a coalescence of said particles into agglomerates, and the ejection of mineral matter into dispersion in said aqueous carrier; recovering said agglomerates from said aqueous carrier; effecting a resolution of said agglomerates into the particles of which they are composed; agitating said particles in slurry with a surface active agent and with a halogenated C 1 or C 2 hydrocarbon in amounts and for a time sufficient to effect a transfer of moisture to those particles having a relatively high mineral matter content, an agglomeration of those particles, and the envelopment of those particles having a lower mineral matter content and a relatively high coal content with the surface active agent; and subsequently subjecting said particles to density differential separation in a body of a parting liquid comprising a halogenated C 1 or C 2 hydrocarbon having a specific gravity intermediate those of the particles having a relatively high coal content and the agglomerates of particles with a relatively high mineral content, whereby said agglomerates will sink to the bottom of said body of parting liquid and those particles which contain a lower proportion of mineral matter and a high proportion of coal will disperse in and migrate to the top of said body of parting liquid; and thereafter separately recovering the floats and the sinks from said body of parting liquid.

Claim 18

A process for recovering coal from a particulate composite in which said coal is associated with mineral matter, said process comprising the steps of: agitating the particles of said composite in slurry in an aqueous carrier containing an agglomeration promoting additive with respect to which the coal is hydrophobic to effect a separation of the coal particles from the mineral matter, a coalescence of said particles into agglomerates, and the ejection of mineral matter into dispersion in said aqueous carrier; recovering said agglomerates from said aqueous carrier; effecting a resolution of said agglomerates into the particles of which they are composed; agitating said particles in slurry with a surface active agent and with a halogenated C 1 or C 2 hydrocarbon in amounts and for a time sufficient to effect a transfer of moisture to those particles having a relatively high mineral matter content, an agglomeration of those particles, and the envelopment of those particles having a lower mineral matter content and a relatively high coal content with the surface active agent; and subsequently subjecting said particles to density differential separation in a body of a parting liquid comprising a halogenated C 1 or C 2 hydrocarbon having a specific gravity intermediate those of the particles having a relatively high coal content and the agglomerates of particles with a relatively high mineral content, whereby said agglomerates will sink to the bottom of said body of parting liquid and those particles which contain a lower proportion of mineral matter and a high proportion of coal will disperse in and migrate to the top of said body of parting liquid; and thereafter separately recovering the floats and the sinks from said body of parting liquid.

Claim 19

A process for recovering coal from a particulate composite in which said coal is associated with mineral matter, said process comprising the steps of: agitating the particles of said composite in slurry in an aqueous carrier containing an agglomeration promoting additive with respect to which the coal is hydrophobic to effect a separation of the coal particles from the mineral matter, a coalescence of said particles into agglomerates, and the ejection of mineral matter into dispersion in said aqueous carrier; recovering said agglomerates from said aqueous carrier; subjecting said agglomerates to density differential separation in a body of a parting liquid capable of effecting a resolution of said agglomerates into sinks of which have a relatively high concentration of mineral matter and therefore migrate to the bottom of said body of parting liquid and into floats which contain a lower proportion of mineral matter than said sinks and a high proportion of coal and therefore rise to the top of said body of parting liquid; and thereafter separately recovering said floats and said sinks from said body of parting liquid.

Claim 20

A process for recovering coal from a particulate composite in which said coal is associated with mineral matter, said process comprising the steps of: agitating the particles of said composite in slurry in an aqueous carrier containing an agglomeration promoting additive with respect to which the coal is hydrophobic to effect a separation of the coal particles from the mineral matter, a coalescence of said particles into agglomerates, and the ejection of mineral matter into dispersion in said aqueous carrier; recovering said agglomerates from said aqueous carrier; subjecting said agglomerates to density differential separation in a body of a parting liquid capable of effecting a resolution of said agglomerates into sinks of which have a relatively high concentration of mineral matter and therefore migrate to the bottom of said body of parting liquid and into floats which contain a lower proportion of mineral matter than said sinks and a high proportion of coal and therefore rise to the top of said body of parting liquid; and thereafter separately recovering said floats and said sinks from said body of parting liquid.

Claim 21

A process as defined in claim 16 which includes the steps of removing agglomeration promoting additive/parting liquid solution formed in effecting the resolution of the agglomerates from the separator in which the density differential separation is carried out; resolving the solution into its constituents; and recycling said constituents.

Claim 22

A process for dissociating coal from a composite in which mineral matter is associated therewith and recovering said coal in agglomerated form, said process comprising the steps of: forming a slurry of said composite in an aqueous carrier with respect to which said mineral matter is hydrophilic; providing in said slurry an agglomeration promoting additive with respect to which said coal particles are hydrophobic in an amount sufficient that agglomeration of the coal can be effected; comminuting the composite while in said slurry to separate mineral matter from the coal and to generate coal particles having freshly exposed surfaces in a controlled environment; mechanically effecting the coalescence of the coal particles into agglomerates and the ejection of mineral matter and water from the agglomerates into dispersion in said aqueous carrier; recovering said agglomerates from said slurry; effecting a resolution of said agglomerates into the particles into which they are composed; and subjecting said particles to density differential separation in a body of a parting liquid, whereby those particles which have a relatively high concentration of mineral matter will migrate to the bottom of said body of parting liquid and those particles which contain a lower proportion of mineral matter and a high proportion of coal will rise to the top of said body of parting liquid; and thereafter separately recovering the floats and the sinks from said body of parting liquid.

Claim 23

A process for dissociating coal from a composite in which mineral matter is associated therewith and recovering said coal in agglomerated form, said process comprising the steps of: forming a slurry of said composite in an aqueous carrier with respect to which said mineral matter is hydrophilic; providing in said slurry an agglomeration promoting additive with respect to which said coal particles are hydrophobic in an amount sufficient that agglomeration of the coal can be effected; comminuting the composite while in said slurry to separate mineral matter from the coal and to generate coal particles having freshly exposed surfaces in a controlled environment; mechanically effecting the coalescence of the coal particles into agglomerates and the ejection of mineral matter and water from the agglomerates into dispersion in said aqueous carrier; recovering said agglomerates from said slurry; effecting a resolution of said agglomerates into the particles into which they are composed; and subjecting said particles to density differential separation in a body of a parting liquid, whereby those particles which have a relatively high concentration of mineral matter will migrate to the bottom of said body of parting liquid and those particles which contain a lower proportion of mineral matter and a high proportion of coal will rise to the top of said body of parting liquid; and thereafter separately recovering the floats and the sinks from said body of parting liquid.