Coal treatment process

Claim 2

A process for treating coal to reduce the level of ash-forming impurities contained therein comprising: a. grinding raw coal to a particle size of less than about 40 microns in a substantially air free environment to form a coal-fraction which comprises a major portion of hydrophobic coal particles and a minor portion of hydrophilic coal particles, and an impurities-fraction comprising hydrophilic impurities particles; b. at least regulating the temperature of the coal at which the grinding step is carried out within the range greater than 220° F. but less than 400° F. to control the amount of said minor portion of hydrophilic coal particles so as to fall substantially below 50% by weight of said raw coal; c. contacting said fractions with an aqueous liquid whereby said hydrophilic impurities particles and said minor portion of hydrophilic coal particles are wetted, but the hydrophobic coal particles are left substantially dry; and d. separating said hydrophobic coal particles from said hydrophilic particles.

Claim 3

A process for treating coal to reduce the level of ash-forming impurities contained therein comprising: a. deaerating raw coal b. grinding said raw coal to a particle size of less than about 40 microns in a substantially air free environment to form a coal-fraction which comprises a major portion of hydrophobic coal particles, and a minor portion of hydrophilic coal particles, and an impurities-fraction comprising hydrophilic impurities particles; c. at least regulating the temperature of the coal at which the grinding step is carried out within the range greater than 220° F. but less than 400° F. to control the amount of said minor portion of hydrophilic coal particles so as to fall substantially below 50% by weight of said raw coal; d. contacting said fractions with an aqueous liquid whereby said hydrophilic impurities particles and said minor portion of hydrophilic coal particles are wetted, but the hydrophobic coal particles are left substantially dry; and e. separating said hydrophobic coal particles from said hydrophilic particles.

Claim 4

A process for treating coal to reduce the level of ash-forming impurities contained therein comprising: a. deaerating raw coal b. grinding said raw coal to a particle size of less than about 40 microns in a substantially air free environment to form a coal-fraction which comprises a major portion of hydrophobic coal particles, and a minor portion of hydrophilic coal particles, and an impurities-fraction comprising hydrophilic impurities particles; c. at least regulating the temperature of the coal at which the grinding step is carried out within the range greater than 220° F. but less than 400° F. to control the amount of said minor portion of hydrophilic coal particles so as to fall substantially below 50% by weight of said raw coal; d. contacting said fractions with an aqueous liquid whereby said hydrophilic impurities particles and said minor portion of hydrophilic coal particles are wetted, but the hydrophobic coal particles are left substantially dry; and e. separating said hydrophobic coal particles from said hydrophilic particles.

Claim 5

A process for beneficiating coal to reduce the level of ash-forming impurities contained therein comprising: a. heating raw coal to reduce the moisture content thereof; b. deaerating said raw coal; c. grinding said raw coal to a particle size of less than about 40 microns in a substantially air free environment to form a coal-fraction which comprises a major portion of hydrophobic coal particles and a minor portion of hydrophilic coal particles, and an impurities-fraction comprising hydrophilic impurities particles; d. at least regulating the temperature of the coal at which the grinding step is carried out within the range greater than 220° F. but less than 400° F. to control the amount of said minor portion of hydrophilic coal particles so as to fall substantially below 50% by weight of said raw coal; e. contacting said fractions with an aqueous liquid whereby said hydrophilic impurities particles and said minor portion of hydrophilic coal particles are wetted, but the hydrophobic coal particles are left substantially dry; f. separating said hydrophobic coal particles from said hydrophilic particles; and g. recovering the separated hydrophobic coal particles.

Claim 6

A process for beneficiating coal to reduce the level of ash-forming impurities contained therein comprising: a. heating raw coal to reduce the moisture content thereof; b. deaerating said raw coal; c. grinding said raw coal to a particle size of less than about 40 microns in a substantially air free environment to form a coal-fraction which comprises a major portion of hydrophobic coal particles and a minor portion of hydrophilic coal particles, and an impurities-fraction comprising hydrophilic impurities particles; d. at least regulating the temperature of the coal at which the grinding step is carried out within the range greater than 220° F. but less than 400° F. to control the amount of said minor portion of hydrophilic coal particles so as to fall substantially below 50% by weight of said raw coal; e. contacting said fractions with an aqueous liquid whereby said hydrophilic impurities particles and said minor portion of hydrophilic coal particles are wetted, but the hydrophobic coal particles are left substantially dry; f. separating said hydrophobic coal particles from said hydrophilic particles; and g. recovering the separated hydrophobic coal particles.

Claim 7

The process claimed in claim 3 wherein heating and deaerating of the coal are carried out simultaneously.

Claim 8

The process claimed in claim 1, 2, or 3 wherein the grinding step is carried out at a temperature below about 350° F.

Claim 9

The process claimed in claim 1, 2, 3, or 4 wherein the controlling step comprises adding to said coal and impurities fractions, prior to the separation step, a reagent for rendering said hydrophilic coal particles hydrophobic.

Claim 10

The process claimed in claim 6 wherein said reagent is a petroleum fraction whose boiling range is such that at the temperature of the coal at which grinding is carried out, a portion of said petroleum fraction is in the vapor stage.

Claim 11

The process according to claim 1, 2, or 3 wherein said separating step is carried out in a separation vessel having an inlet, a discharge, and wall means disposed between said inlet and said discharge defining a separation zone, said separation zone, being surrounded at its outer periphery by a aqueous separation medium, and comprises subjecting said fractions to centrifugal force in said separation zone, collecting a substantial portion of the hydrophilic particles in said aqueous medium, and exhausting the hydrophobic coal particles from the interior of said separation zone through said discharge.

Claim 12

The process according to claim 1, 2 or 3 wherein said separating step is carried out in a separation vessel having an inlet, a discharge, and wall means disposed between said inlet and said discharge defining a separation zone, said separation zone having an aqueous separation medium adjacent said discharge and comprises introducing said fractions through said inlet into said separation zone, accelerating said fractions through said separation zone, collecting a substantial portion of the hydrophilic particles in said aqueous medium, and exhausting the hydrophobic coal particles from said separation zone through said discharge.

Claim 13

The process according to claim 6 wherein said separating step is carried out in a separation vessel having an inlet, a discharge, and wall means disposed between said inlet and said discharge defining a separation zone, said separation zone being surrounded at its outer periphery by a aqueous separation medium, and comprises subjecting said fractions to centrifugal force in said separation zone, collecting a substantial portion of the hydrophilic particles in said aqueous medium, and exhausting the hydrophobic coal particles from the interior of said separation zone through said discharge.

Claim 14

The process according to claim 6 wherein said separating step is carried out in a separation vessel having an inlet, a discharge, and wall means disposed between said inlet and said discharge defining a separation zone, said separation zone having an aqueous separation medium adjacent said discharge and comprises introducing said fractions through said inlet into said separation zone, accelerating said fractions through said separation zone, collecting a substantial portion of the hydrophilic particles in said aqueous medium, and exhausting the hydrophobic coal particles from said separation zone through said discharge.

Claim 15

The process claimed in claim 1, 2 or 3 wherein the steps of said process are carried out continuously.

Claim 16

The process claimed in claim 6 wherein the steps of said process are carried out continuously.

Claim 17

The product produced according to the process claimed in claim 6.