Abstract: Blast furnace coke containing low grade coal in a high blending ratio is manufactured by a method which comprises blending not less than 60% of a blended coal having an adjusted total moisture content of not more than 4% with not more than 40% of briquettes and carbonizing the resultant mixture.The blended coal consists essentially of not less than 80% of coking coal and not more than 20% of low grade coal. When coking coal of a kind which has its coking property segregated according to its grain size distribution is pulverized and classified by sifting and the portion of fine particles is used as mixed with the coking coal, the blending ratio of the low grade coal in the blended coal can be increased to up to 35%. The briquettes consist essentially of not less than 10% of coking coal and not more than 90% of low grade coal.

Abstract: The process for the production of molded metallurgical coke from dried coal or fine coal mixtures with a low swelling index particularly highly volatile fine coal comprises mixing normal washed fine coal or fine coal mixtures of a grain size of from 0 to 10 mm and a swelling index of not more than 5 with a binder, pressing the mixture into briquettes, oxidizing the briquettes in a continuous material flow stream, and coking the oxidized briquettes continuously in an oven chamber by supplying indirectly and exhausting the coke oven gases with a temperature of 300.degree. to 1200.degree. C.

Abstract: The bulk density and throughput characteristics of coking coal are improved by treating the coal with a surfactant and a combination of fuel oil and alcohol or of solid lubricant and water, the surfactant being soluble in, and increasing the spreading coefficient of, fuel oil or water, as the case may be.

Abstract: An impregnated carbonaceous material which can be mixed with basic coal to form a mixture which, once roasted, forms an effective shaft furnace coke. The impregnated carbonaceous material is formed by finely crushing an inert carbonaceous material such as powdered coke, coal gasification char, coal liquifaction residue coal, oil coke, and semi-dry-distilled char, and mixing and impregnating the crushed carbonaceous material with an aromatic pitch such as coal tar, coal tar pitch, asphalt, and pitch obtained by heat-treating or solvent extracting an asphalt. The mixing is conducted at a temperature above the aromatic pitch melting point. The impregnated carbonaceous material contains preferably 50 to 95 parts by weight of crushed inert carbonaceous material and 5 to 50 parts by weight aromatic pitch.

Abstract: A method for recovering and utilizing heat of coke-oven gas, which comprises: through heat exchange with a high-temperature coke-oven gas generated from a coke oven battery and containing vaporized coal tar, vaporized low boiling point substances and dust, drying and preheating a blended raw material coal fine to be charged into coking ovens of said coke oven battery, and, on the other hand, causing most of said coal tar contained in said coke-oven gas to condense and deposit onto the particle surfaces of said coal fine during the process of said heat exchange, thereby recovering and utilizing sensible heat and condensation heat of said coke-oven gas and substances contained therein, and at the same time, eliminating most of the contained coal tar from said coke-oven gas.

Abstract: A method reducing fine dust emission during the time that predried and preheated coal is charged into coke ovens comprises directing wet coal to be carbonized into direct contact with a hot process gas so that the coal is transported dry and heated, directing the hot process gas with the heated coal to a plurality of different separators in succession with the first separator being set to separate only around from 80 to 90% of the total amount of the coal and without separating the fine dust, and a subsequent separator separate the remaining amount of the solid matter including the fine dust, compacting the dust removed from all of the separators and mixing them together, and charging the compacted mixed dust into the coke oven. The apparatus for effecting the invention includes a material separator which is designed as a gravity separator or gravity sifter which is arranged to discharge into a connection between the mixed and compacted dust separator in separate additional separators.

Abstract: Particulate coal is contacted with a hydrogen donor solvent, preferably a vapor phase hydrogen donor solvent, to swell the coal particles and, thereafter, the swollen coal particles are subjected to coal liquefaction conditions in the absence of liquid phase solvent.

Abstract: An integrated coal pretreatment, liquefaction and gasification process is provided in which particulate coal is contacted with a vapor phase hydrogen donor solvent to swell the coal particles. The swollen coal particles are subjected to coal liquefaction conditions at relatively low temperatures. The solid residue of the coal liquefaction stage is subjected to pyrolysis conditions at relatively high temperatures to produce an additional amount of hydrocarbonaceous oil. The solid residue of the pyrolysis stage is gasified by treatment with steam and a molecular oxygen-containing gas to produce a hydrogen-containing gas.

Abstract: Particulate coal is contacted with a vapor phase hydrogen donor solvent to swell the coal particles and, thereafter, the swollen coal particles are subjected to coal liquefaction conditions in the presence of a liquid phase solvent.

Abstract: The present invention is an improvement in the known process of making a coking feedstock from non-caking or weakly caking coals for slot-type coke ovens wherein the coal is subjected to solvent extraction; and at least the non-distillable extract in the effluent slurry product, after removal of part or all of the solvent, is mixed with carbonaceous solids to serve as a binder therefor. The improvement resides in the use of fluidizer char (which is produced by the low temperature carbonization of coal in a fluidized bed) as the carbonaceous solids. The fluidizer char is preferably mixed with the coal extract slurry (after removal of solvent) in a liquid state at elevated temperatures under pelletizing and non-carbonizing conditions. The pelletized product, after cooling and crushing, is suitable as part or all of the coking feedstock for coke ovens.

Abstract: Metallurgical coke is made from coking a blend of coal which is comprised of reformed coal and another suitable coking coal. Reformed coal hereof is preferably made by the method which comprises dissolving at least one component selected from the group consisting of bituminous coal, subbituminous coal, brown coal and lignite in a hydrocarbon solvent, and recovering a reformed coal from said solution.

Abstract: A process is described for producing metallurgical coke from poor coking coals in which there is combined with the poor coking coals a small amount of an additive consisting of a bitumen residue obtained from hydrocracking of bitumen from tar sands. The residue used is that from vacuum distillation of a heavy hydrocarbon bottoms material obtained from hydrocracking of the bitumen. A high boiling organic residue from vacuum distillation to an equivalent atmospheric boiling temperature of 524.degree. C. is preferred. The novel additive is superior in its ability to penetrate into cavities and provide excellent bonding of the components of the coal.

Abstract: Bodies are press-molded from a mixture of particulate fuel and a binder. These bodies are heated to a temperature between about 600.degree.-900.degree. C. in a rotary furnace to degas them. The degassing is carried out without subjecting the bodies to mechanical stresses and without permitting combustion of the expelled volatile gases. The resulting shaped coke has a greatly improved abrasion resistance.

Abstract: A method of preparing coals for coking in a conventional coke oven includes agglomerating the loose coal, in combination with a binder, into flakes, mixing the flakes with non-agglomerated coal, and charging the mixture into the coke oven in the conventional manner. The method provides for the utilization in a conventional coke oven, of coals that are marginal in coking quality, greater bulk densities of the coal as charged into a conventional coke oven, acceptable shatter resistance and physical stability of the coke produced, and acceptable carbonization pressure on the coke oven walls.

Abstract: Coal is dissolved in a hydrocarbon solvent, heated and purged of insolubles to form various types of solvent purified coal having different degrees of depolymerization. These various types of solvent purified coal are then coked to yield a variety of green coke products. The solvent purified coal is useful as a raw material for needle-like green coke when the value of its (N+O+S)/C atomic ratio is less than 0.0445; for coarse mosaic green coke when the value is in the range of from 0.0445 to but excluding 0.0516; for mosaic green coke when the value is in the range of from 0.0516 to but excluding 0.0584; for fine mosaic green coke when the value is in the range of from 0.0584 to but excluding 0.0645; and for glassy green coke when the value is equal to or greater than 0.0645.

Abstract: An improved process for making metallurgical coke is provided as follows. An effluent slurry consisting essentially of coal extract, solvent and undissolved coal is obtained from the liquefaction of coal by solvent extraction. Solvent is removed from the slurry by distillation to produce a bottoms product which contains non-distillable extract, undissolved coal and residual solvent. The bottoms product is flowable at elevated temperatures below its carbonizing temperature and solidifiable at lower temperatures. The bottoms product is blended with sufficient finely divided hot coaly solids (unsuitable per se for making metallurgical coke) in a hot blending zone which is maintained at a temperature above the softening point of the non-distillable coal extract and below the coking temperature thereof to produce a solidifiable product which, in particulate solidified state, serves as part or all of the feedstock to a coking zone to produce coke suitable for use in a blast furnace.

Abstract: Process for the preparation of a moulded coke according to which agglomerates are heated in a non-oxidizing atmosphere, this process being characterized in that the agglomerates are prepared by compression from a paste containing:from 60 to 85% by weight of non-cokable coals,from 10 to 30% by weight of agglutinating coalshaving a swelling index greater than 2, andfrom 5 to 13% by weight of binder,which paste, when heated at 6.degree. C. per minute in the ARNU dilatometer gives a contraction of between 3 and 15%, preferably between 5 and 10% and a swelling of zero or near 0, and in that the agglomerates are heated in a non-oxidizing atmosphere from a temperature of about 100.degree. C. to a temperature of at least about 700.degree. C., with a rate of heating of between 7 and 14.degree. C. per minute.

Abstract: A method of manufacturing blast furnace coke wherein said coke is obtained by a process in which coal to be used for making briquettes is mixed with a caking substance having a softening point of 40.degree.-250.degree. C. with or without a solvent having fluidity at the mixing temperature and dissolvable to said caking substance, the resultant mixture being mixed by means of a powerful mixer capable of applying mixing energy of 0.01KW/Kg or more at a temperature of 40.degree.-250.degree. C. for 1-10 minutes, while a heating medium such as steam is passed therethrough and is then subjected to briquetting with a roll press. The briquette obtained is either carbonized directly or after blending with coal ready for coke oven charging.

Abstract: Solid carbonaceous materials are pyrolyzed by introducing a low velocity stream of carbonaceous material into a cyclone reactor-separator and introducing a low velocity stream of a particulate source of heat into the cyclone reactor-separator at an angle inclined toward the path of travel of the carbonaceous material. A high velocity stream of the particulate source of heat is introduced into the cyclone reactor-separator along the inner surface of the separator to prevent carbonaceous material from caking along the walls of the separator. The velocity of the high velocity stream is at least about 50 feet per second greater than the velocity of both low velocity streams. The cyclone reactor separator induces separation of solids consisting of a particulate carbon containing solid residue of pyrolysis and particulate heat source from a vapor stream which contains hydrocarbon products of pyrolysis.

Abstract: A method of producing blast furnace coke from bituminous coals, particularly coals having poor coking capacities in which the coal to be carbonized is ground, predried or preheated, mixed with binders, compressed or formed into briquets having small mechanical resistances and charged into oven chambers, is characterized by fine coals or fine coal mixtures having a swelling index in mixture according to DIN 51741, smaller than 7, and preferably, below 6, and comprising more than 50% of poorly or non-baking coal having a content of volatile matter in excess of 30% or less than 20% which coals or coal mixtures are ground up to attain asurface per unit mass, according to DIN 66145, of from 400 cm.sup.2 to 1200 cm.sup.2 per gram, and with from 3% to 8% by weight of organic binders, compressing the mixture to form it into a briquet at a temperature range of from 70.degree. C. to 300.degree. C.

Abstract: Solid organic wastes are slurried with hot coker recycle feed or fresh petroleum feedstocks at temperatures within the range from about 300.degree. to 1000.degree. F and the resulting mixture is coked to produce gas, oil, and coke. The oil can be used as clean liquid fuel, but preferably it is used as catalytic craker feed since it is a particularly suitable cracking stock and produces high yields of gasoline. This process affords a low-cost waste disposal method by a process compatible with current petroleum refining technology.

Abstract: Process for manufacturing reformed coal which comprises the steps of (a) dispersing coal into a mixed oil which is comprised of a coal oil having a boiling point between about 150.degree. C. and 500.degree. C. and a petroleum oil having a boiling point higher than that of kerosene; (b) subjecting the coal and oil dispersion to hydrogenation conditions sufficient to depolymerize the coal; (c) separating a substantially liquified coal solution from the product of hydrogenation, and (d) distilling the liquified coal solution to recover a reformed coal. Preferably, a portion of the coal oil is recycled from the distillation stage and a portion of the hydrogen needed for hydrogenation is produced from light fractions from the distillation stage.

Abstract: A plurality of different types of raw material coal fines are sieved to a size not exceeding 1.5 mm; said sieved raw material coal fines are blended so as to satisfy the following conditions:(a) AP index: 75 at the minimum,(b) Mean maximum reflectance: 1.20% at the minimum, and(c) A [dilatation] - [contraction] value of from -2 to +5% when carbonized under conventional conditions in a horizontal type coke oven battery at a heating rate of 5.degree. C/min. (350.degree. - 600.degree. C);said blended raw material coal fines thus obtained are mixed with a binder and formed to produce a formed coal; and then, said formed coal thus obtained is charged into a horizontal type coke oven battery and carbonized, whereby a high-strength formed coke for blast furnace is a slight mutual agglomeration is manufactured.

Abstract: A process for converting relatively ash-free solid polymeric wastes to more valuable liquid, solid, and gaseous products which comprises mixing rubber and/or plastic wastes at high temperatures in a refractory petroleum stream and catalytically cracking the mixture.

Abstract: A method of improving the mechanical resistance of coke comprises forming a liquor of fine grained coal and oil with the oil being of from 5% to 30% of the total weight, forming coal pellets of the liquor at an increased temperature of from approximately 80.degree. to 100.degree. C, and heating the pellets to transform them into coke in a known coking process. Prior to being carbonized, the pellets are advantageously coated with a separating layer of a substance preventing agglomeration, such as hematite ore, lime, fine coke, etc.

Abstract: With the use of low-fluidity blended raw material coal fines having a maximum fluidity of up to 20 d.d.p.m. as an inner core material, and coal fines having a maximum fluidity of at least 30 d.d.p.m. or a bituminous material having a C/H ratio of from 0.7 to 1.9 as an outer envelope material, green composite briquettes are formed by covering said inner core material with said outer envelope material. Said green composite briquettes thus formed are charged into a conventional coke oven battery and carbonized by an ordinary process, whereby a high-strength metallurgical formed coke in a slight mutual agglomeration is produced.

Abstract: Carbonaceous materials are pyrolyzed by simultaneous feed of the carbonaceous materials and a particulate source of heat to a cyclone reactor-separator wherein the centrifugal forces separate the vaporized product of pyrolysis from the solids. The carbon in the solids is partially combusted for recycle to the cyclone reactor separator and the vaporized products quenched and recovered. The yield of liquid hydrocarbons may be maximized.

Abstract: The specification discloses apparatus and methods for recovery of coal fines and for recycling thereof incidental to a self-contained system for charging preheated coal into coke ovens. The apparatus enables a system for charging preheated coal into coke ovens to meet pollution control regulations. The apparatus comprises four circulating streams of liquid for carrying coal fines in a slurry, namely, the charge main liquor circuit, the excess recycle gas scrubber circuit, the charge line condenser circuit and the charge bin vent condenser circuit. The -28 mesh coal with the liquor from the various circuits goes to a clarifier or thickener. Floating fines from top and settled fines from the bottom of the thickener are pumped via a fines tank to filters from which the solid or coagulated fines are restored to the wet coal feed to the heaters.

Abstract: Process for producing formed coke for metallurgical use from coal powder by continuously heating with a high temperature gas as heating medium for carbonizing agglomerated coal which are made of coal powder and a binder such as coal tar, pitch and petroleum asphalt, comprising providing tuyeres for introducing gas at the middle and the lower parts of an upright type carbonization oven, adjusting temperature of the gas to be supplied to the tuyere at the middle part at 600.degree. to 800.degree. C, adjusting the supply rate of the gas so as to maintain the temperature of the gas on the agglomerated coal at 300.degree. to 500.degree. C, and further adjusting the supplied heat to the lower part of the carbonization oven including the lower tuyere to amount less than 50% of the total supplied heat.

Abstract: A process for preparing blast furnace cokes which contain large amounts of low-grade coal which comprises the steps of adding a binder to a coal for making briquettes which comprises a substantially low-grade coal such as non- and/or poorly-coking coal; either alone or when blended in an amount of up to about 40% or more with a charging coal; mixing the binder and the coal briquetting the mixture in a roll press to form briquettes of two or more types; blending the resulting briquettes of different types with a charging coal in a total amount of about 35% or more of the briquettes based on the charging coal and, to prepare a blended charging coal; and carbonizing the blended charging coal in a coke oven.

Abstract: This invention is directed to a process for converting coal into useful liquids, solids, and gases, by combined processes of coal carbonization and liquefaction in which the carbonization reaction yields hydrogen suitable for the liquefaction. The heavy liquid products from the liquefaction and the carbonization may be combined with the solid char to form a metallurgical coke. Other liquids may be treated and converted into useful industrial hydrocarbon chemicals. The gases from the combined reactions yield a fuel gas as well as a hydrogen stream suitable for use in the overall processing.

Abstract: In gas-solids contacting processes involving the transfer of granular solids from a high-temperature, non-oxidizing treating zone through an enclosed conduit to a combustion zone, the transfer of gases between the treating zone and the combustion zone is prevented by using a novel steam sealing technique which avoids the use of mechanical sealing means and differential pressure controllers. Steam is injected into the system between the two contacting zones, and by the use of flow rate controllers and a pressure controller, a portion of such steam is forced at all times to flow through the combustion zone, while another portion thereof is withdrawn from the transfer conduit in admixture with a portion of net off-gas from the treating zone. The control system is particularly adapted for use in oil shale retorting, wherein coke on the retorted shale is burned in a combustion zone.

Abstract: A coke oven system is provided having a coke oven preferably with pipeline charging for converting coal into coke. Carryover fines are collected from the coke oven and preferably a preheater therefor, and then agitated by agitator means and the collected carryover fines thereby agglomerated. Preferably, the carryover fines are first mixed with water to form an aqueous mixture, and then agglomerated. The agglomerated carryover fines are then preferably separated from the aqueous mixture by separated means. The agglomerated carryover fines are preferably conditioned in dryer means and recirculated to the coke oven preferably through a preheater.

Abstract: A process for the conversion of carbonaceous materials such as coal, tar sands or the like to clean liquid and gaseous fuels.

Abstract: Solid carbonaceous materials are pyrolyzed by introducing a low velocity stream of carbonaceous material into a cyclone reactor-separator and introducing a low velocity stream of a particulate source of heat into the cyclone reactor-separator at an angle inclined toward the path of travel of the carbonaceous material. A high velocity stream of the particulate source of heat is introduced into the cyclone reactor separator along the inner surface of the separator to prevent carbonaceous material from caking along the walls of the separator. The cyclone reactor separator induces separation of solids consisting of a particulate carbon containing solid residue of pyrolysis and particulate heat source from a vapor stream which contains hydrocarbon products of pyrolysis.

Abstract: Solid carbonaceous materials are pyrolyzed by feeding the carbonaceous material along with a particulate source of heat to a fast fluidized bed contained within a vertically disposed duct. An internally circulating stream of spent particulate source of heat and carbon containing solid residue of the pyrolysis of the carbonaceous material flows upwardly along the inner surface of the duct, thereby preventing carbonaceous material from caking on the duct.

Abstract: A method for inhibiting dust formation while feeding coal into a coking chamber, comprising preheating coal and subsequently contacting the coal with an aqueous solution of 30-70% by weight of waste sulfite liquor in amounts of about 0.5 to 1.0 parts by weight of said solution per 1000 parts by weight of said coal.

Abstract: The invention relates to the upgrading of coal for coking purposes and improved cokes resulting from such upgrading. Pitch obtained as a by-product of pressure-gasification (Lurgi-process) is used as an additive either alone or blended with SRC. The additive is employed in amounts of 1% and 50% by mass, preferably 5 to 15% of the total blend. The additive preferably has an R-and-B softening temperature above 80.degree. C. The additive can be subjected to various treatments, e.g. heating in presence of hydrogen, to improve its characteristics.

Abstract: This invention provides a method for solubilizing wood or wood and coal mixtures in a highly aromatic refinery petroleum solvent to produce homogeneous compositions which have a flowable pitch-like consistency at ambient temperatures. The invention compositions are directly applicable as liquid fuels, or can be further processed into other desirable products.

Abstract: Process for the preparation of a composition comprised mainly of carbon and containing only a small amount of ash, nitrogen and sulfur, said process comprising:A. drying a hydrous soot with hot flue gas of about 600.degree. C in a direct current-operated dryer to form a dried soot having a water content of about 5 to about 20 percent by weight;B. carbonizing said dried soot in a vertical flue oven by heating at a flue temperature of about 900.degree. to about 1300.degree. C for about 25 to about 40 hours; andC. drying, comminuting and classifying the resulting composition.The composition is useful as a coking agent, filter aid, and in the production of carbon and graphite products.

Abstract: Formcoke suitable for use in a blast furnace is made from a non-caking or weakly caking coal by converting the coal to an agglomeratable material consisting essentially of a blend of the entire product (without separation of extract and undissolved solids) obtained by solvent extraction of the coal in the presence of hydrogen and a suitable amount of hydrocarbonaceous solids. The agglomeratable material is agglomerated under low temperature carbonizing conditions and the agglomerates are thereafter calcined to produce strong formcoke.

Abstract: Coal is preheated and contacted with 0.5 to 3 percent by weight of moist coal tar, preferably bituminous coal tar. The thus-treated coal is admitted into a coke oven through the ceiling of the latter. The coal is poured into the coke oven, rather than being blown in, and is permitted to descend into the coke oven under the influence of gravity. Preferably, the coal is poured into the coke oven through at least two or three openings in the ceiling thereof. The coal tar serves to bind finely divided coal particles to the coarser particles and, in this manner, the development of dust during the introduction of the coal into the coke oven is restricted and, concomitantly, the danger of ignition or explosion is reduced.

Abstract: One of the problems encountered when feeding dry or preheated coal into coking chambers resides in that dust is generated. This dust is indesirable since it can form deposits which are difficult to remove. A method of inhibiting the dust formation when coal is fed into coking chambers is disclosed. The method involves contacting the coal with used motor oil prior to the introduction of the coal into the coking chambers. The utilization of used motor oil for inhibiting dust formation provides the advantages of economy and reduction of environmental pollution.

Abstract: A method for producing pitch and coke which comprises heating a starting oil material in the presence of a powdery carbonaceous substance at a temperature of 350.degree. to 600.degree. C under an increased pressure of at least 2 kg/cm.sup.2 gauge to produce pitch, coke and oil and separating the pitch and coke from the oil, said starting oil material being distillation residue of crude oil having a Conradson carbon residue of 1 to 25 weight percent and containing 20 to 80 weight percent of substances boiling at a temperature of at least 600.degree. C and less than 10 weight percent of substances boiling at a temperature lower than 350.degree. C, said powdery carbonaceous substance having a Conradson carbon residue of at least 50 weight percent and being added to the starting oil material in such an amount that Conradson carbon residue of the carbonaceous material is in the range of one-tenth to ten times that of the starting oil material.

Abstract: In a continuous, solids upflow, gas downflow shale retorting process carried out at superatmospheric pressures, hydrostatic sealing means are provided at the shale inlet and retorted shale outlet ends of the retort, thereby avoiding the need for mechanical sealing means, lock vessels, etc. The raw shale is fed into the retort through a standing reservoir of product oil, or preferably a light fraction thereof, and the retorted shale is discharged from the retort through a water quenching zone and seal, in the lower portion of which is maintained a sufficient hydrostatic head of water to prevent the discharge therethrough of retort gases. Steam generated in the quench zone, containing some entrained hydrocarbonaceous matter, is treated in a multistage cooling and condensing manner for gas cleanup and for recovery of heat and an oil-free water condensate for recycle to the water sealing and quench zones.

Abstract: In a continuous, solids upflow, gas downflow shale retorting process carried out at superatmospheric pressures, hydrostatic sealing means are provided at the shale inlet and retorted shale outlet ends of the retort, thereby avoiding the need for mechanical sealing means, lock vessels, etc. The raw shale is fed into the retort through a standing reservoir of product oil, or preferably a light fraction thereof, and the retorted shale is discharged from the retort through a water quenching zone and seal, in the lower portion of which is maintained a sufficient hydrostatic head of water to prevent the discharge therethrough of retort gases. Steam generated in the quench zone, containing some entrained hydrocarbonaceous matter, is treated in a multistage cooling and condensing manner for gas cleanup and for recovery of heat and an oil-free water condensate for recycle to the water sealing and quench zones.

Abstract: Coal particles are heated and further particulized at a preheat stage employing a preheat gas. Some of the finer coal particles are puffed up by the preheating step. Most of the preheated coal particles are separated from the preheat gas, but some of the finer coal particles remain with the preheat gas. The coal particles separated from the preheat gas are oiled and eventually transported by a carrier gas through a pipeline into a coke oven. The preheat gas and the finer coal particles remaining therewith are separated from each other utilizing a wet scrubber at which the finer coal particles undergo flocculation. Oil vapor vented from the coal particles headed for the coke oven is directed to the wet scrubber to aid in the flocculating step. The flocculated coal particles are separated from the scrubber liquid in a flotation cell. The overflow from the flotation cell is filtered, and the filter cake comprising coal particles is employed as a fuel.