Abstract: A method for removing ash from a solid carbon material: Reaction conditions are mild, and ash may be removed more effectively. The ash removing method comprises: S1) mixing an alkaline sub-molten salt medium and a solid carbonaceous material to be treated, heating so that alkali and ash in the solid carbonaceous material to be treated react in the alkaline sub-molten salt medium, and performing solid-liquid separation on a mixed slurry resulting from the reaction to obtain a first solid product and an alkali treatment solution, wherein in the alkaline sub-molten salt medium, the mass fraction of the alkali is greater than or equal to 50%; S2) using an acid solution to perform acid cleaning treatment on the first solid product, and performing solid-liquid separation again to obtain a second solid product and an acid cleaning solution.

Abstract: An experimental method for coal desulfurization and deashing using permeation and solvating power of a supercritical fluid includes the following steps. The coal sample is ground and loaded into an extraction kettle with a cover. An inlet valve and an outlet valve of the extraction kettle are opened to circulate the supercritical CO2 fluid in the extraction kettle. The extraction kettle is sealed. By adjusting a temperature and a pressure in the extraction kettle, the supercritical CO2 fluid is kept at its critical point and permeates the coal sample to dissolve organic sulfur, inorganic sulfur and ash in the coal sample. The extraction kettle is depressurized, and the temperature in the extraction kettle is adjusted to gasify the supercritical CO2 fluid. The organic sulfur, the inorganic sulfur and part of the ash are separated from the supercritical CO2 fluid and precipitated at a bottom of the extraction kettle.

Abstract: The present invention relates to an extraction apparatus for extracting at least one constituent in a substance. The extraction apparatus comprises an extractor, an extraction separator and an extraction condenser. The extractor is used to mix the substance and an extraction fluid, wherein the extraction fluid is a subcritical fluid. The extraction separator is connected to the extractor for receiving and heating the extraction fluid to gasify the extraction fluid and to separate the constituent and the gasified extraction fluid. The extraction condenser is connected to the extraction separator and the extractor for receiving and liquefying the gasified extraction fluid from the extraction separator and sending the liquefied extraction fluid to the extractor.

Abstract: A method for upgrading coal fines by separating out at least some mineral components is provided. The method comprises the treatment of optionally graded coal fines with microalgae in aqueous medium to form a slurry under conditions that permit adsorption of microalgae onto particles of coal fines. The slurry is treated to separate a first fraction that is rich in coal fines together with adsorbed microalgae thereon from a second fraction that has more mineral components in it than does the first fraction and processing the first fraction to recover upgraded coal fines therefrom. Contacting is preferably carried out in a manner aimed at loading the coal fines generally evenly with microalgae adsorbed thereon in an amount of from 5 to 15% by weight of coal fines. Separation may be carried out by sedimentation, cyclone separation or flotation.

Abstract: Provided is an ash-free coal production method without the need to once re-liquefy and form an ash-free coal. The ash-free coal production method includes an extraction step of mixing coal with a solvent to prepare a slurry and heating the slurry to extract a solvent-soluble coal component; a separation step of separating a solution containing the solvent-soluble coal component from the slurry obtained from the extraction step; an ash-free coal obtaining step of evaporatively separating the solvent from the solution separated in the separation step to obtain an ash-free coal. The ash-free coal obtaining step in the production method is performed so that the solvent is evaporatively separated from the solution to give a liquid ash-free coal, and the liquid ash-free coal is brought into contact with a solidifier (e.g., water) to solidify into a predetermined shape.

Abstract: Provided is a method that controls and uniformizes fluidity of ash-free coal. The method includes the steps of obtaining an ash-free coal by removing a solvent from a solution containing a coal component dissolved therein (ash-free coal obtaining step (solvent recovering unit 8)); and mixing a plurality of coals of different types or components thereof, where the coals are capable of individually giving ash-free coals having different fluidities (mixing step (see reference signs B1 to B6)). The ash-free coal obtaining step (solvent recovering unit 8) obtains the ash-free coal by removing the solvent from the solution containing components of the coals which have been mixed.

Abstract: A process for demineralizing coal includes the steps of forming a slurry of coal particles in an alkali solution, the slurry containing 10-30% by weight coal, maintaining the slurry at a temperature of 150-250° C. under a pressure sufficient to prevent boiling, separating the slurry into an alkalized coal and a spent alkali leachant, forming an acidified slurry of the alkalized coal, the acidified slurry having a pH of 0.5-1.5, separating the acidified slurry into a coal- containing fraction and a substantially liquid fraction, subjecting the coal-containing fraction to a washing step, particularly a hydrothermal washing step, in which the coal-containing fraction is mixed with water and a polar organic solvent or water and an organic acid to form a mixture and separating the coal from the mixture. The demineralized coal has an ash content of from 0.01-0.2% by weight and can be used a feed to a gas turbine.

Abstract: Sorbent compositions containing halogen and calcium are added to coal to mitigate the release of sulfur and/or other harmful elements, including mercury, into the environment during combustion of coal containing natural levels of mercury.

Abstract: Sorbent compositions containing halogen and calcium are added to coal to mitigate the release of sulfur and/or other harmful elements, including mercury, into the environment during combustion of coal containing natural levels of mercury.

Abstract: Sorbent compositions containing halogen and calcium are added to coal to mitigate the release of sulfur and/or other harmful elements, including mercury, into the environment during combustion of coal containing natural levels of mercury.

Abstract: A method of processing coal to remove contaminants by mixing coal in a solution of potassium permanganate in a selected concentration range, rinsing the coal, mixing the coal in a solution of ammonia hydroxide in a selected concentration range to cause the solution to be brought into contact with the surfaces and pores of the coal, discharging the processed coal from the second reaction vessel, monitoring the process to detect when the concentration of aqueous ammonia in the second reaction vessel has fallen below the selected range, and feeding aqueous ammonia solution with an ammonia concentration in or above the selected range to the second reaction vessel to return the solution to within the selected range.

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 processing coal to remove sulfur and other contaminants by mixing coal in a solution of aqueous ammonia having a selected concentration range (preferred range of 3%-5%) of ammonia to water in a reaction vessel. The mixing causes the solution to be brought into contact with the surfaces and pores of the coal. The process is monitored to detect when the concentration of aqueous ammonia in the reaction vessel has fallen below the selected range, and aqueous ammonia with an ammonia concentration in or above the selected range is fed into the reaction vessel to return the solution to within the selected range. The cleaned coal may be rinsed and dried, or dried without rinsing to form an ammonia coating on the coal surfaces and pores. Several plant layouts to practice the method are described.

Abstract: The feeding of coal slurries into a gasifier for the production of synthesis gas is improved by modifying the rheological properties of the coal particles so that conventional liquid transfer equipment can be used in the feed transfer process to the gasifier. The coal particle surface modification is accomplished by adsorbing asphaltenes derived from petroleum onto the surfaces of coal particles prior to and/or during contact with the slurry liquid. The coal particles with their surfaces thus modified exhibit lower particle-particle interaction in the liquid slurries to form a shear independent Newtonian fluid or a weakly shear thickening pseudoplastic fluid. The rheological properties of the slurries permit them to be transported reliably into a pressurized, entrained feed gasifier vessel using convention slurry pumps with a low potential expenditure of energy.

Abstract: A sulfur compound adsorbent for solvent extraction of coal and methods using the same to adsorb sulfur compounds and refine coal are provided. The adsorbent for solvent extraction of coal serves to remove sulfur compounds from an organic solvent containing a coal's combustible component resulting from solvent extraction of low-grade coal and is composed of any one or a mixture of two or more selected from among alkali earth metal oxide, alkali earth metal hydroxide, aluminum oxide and activated carbon.

Abstract: Sorbent compositions containing halogen and calcium are added to coal to mitigate the release of sulfur and/or other harmful elements, including mercury, into the environment during combustion of coal containing natural levels of mercury.

Abstract: Sorbent compositions containing halogen and calcium are added to coal to mitigate the release of sulfur and/or other harmful elements, including mercury, into the environment during combustion of coal containing natural levels of mercury.

Abstract: A method for removing at least one impurity from coal is described herein. The method includes providing coal comprising a plurality of impurities and contacting the coal with an acid solution in a reaction chamber. At least one of the impurities reacts with the acid solution to produce one or more first products soluble in the acid solution. The method further includes removing at least a portion of the acid solution including at least a portion of the first products from the reaction chamber and adding a nitrate composition to the reaction chamber to form a nitrate solution. At least one of the impurities, at least one of the first products, or combinations thereof react with the nitrate composition to produce one or more second products soluble in the nitrate solution. The method still further includes removing at least a portion of the nitrate solution including at least a portion of the second products from the reaction chamber.

Abstract: A process for treating mixtures of solid coal and fly ash containing metallic oxides, silicon dioxide and sulfur compounds in order to produce treated coal and substantially pure silicon dioxide comprising (1) reacting a mixture of the coal and fly ash with hydrogen fluoride in water to produce a liquid stream comprising silicon fluoride and metal fluorides and a solids stream comprising unreacted coal and sulfur compounds; (2) reacting the sulfur compounds with metallic nitrates dissolved in water to form an aqueous solution of nitrate, metallic and sulfur ions; (3) separating the aqueous solution of nitrate, sulfur and metallic ions from the solid coal; (4) washing the previously treated solid coal with water; (5) reacting the silicon fluorides and metal fluorides with metallic nitrates in an aqueous mixture to form solid silicon dioxide; and separating the solid silicon dioxide from the aqueous mixture.

Abstract: A method of processing coal to remove sulfur and other contaminants by mixing coal in a solution of aqueous ammonia having a selected concentration range (preferred range of 3%-5%) of ammonia to water in a reaction vessel. The mixing causes the solution to be brought into contact with the surfaces and pores of the coal. The process is monitored to detect when the concentration of aqueous ammonia in the reaction vessel has fallen below the selected range, and aqueous ammonia with an ammonia concentration in or above the selected range is fed into the reaction vessel to return the solution to within the selected range. The cleaned coal may be rinsed and dried, or dried without rinsing to form an ammonia coating on the coal surfaces and pores. Several plant layouts to practice the method are described.

Abstract: Processes and compositions are provided for decreasing emissions of mercury upon combustion of fuels such as coal. Various sorbent compositions are provided that contain components that reduce the level of mercury and/or sulfur emitted into the atmosphere upon burning of coal. In various embodiments, the sorbent compositions are added directly to the fuel before combustion; are added partially to the fuel before combustion and partially into the flue gas post combustion zone; or are added completely into the flue gas post combustion zone. In preferred embodiments, the sorbent compositions comprise a source of halogen and preferably a source of calcium. Among the halogens, iodine and bromine are preferred. In various embodiments, inorganic bromides make up a part of the sorbent compositions.

Abstract: A process of treating high sulfur coal to reduce sulfur dioxide emission when the high sulfur coal is burned comprising placing coal in pressure tank (16) of reduced pressure sufficient to fracture a portion of the coal by withdrawing ambient fluids trapped within the coal. The fractured coal is contacted with an aqueous silica colloid composition supersaturated with calcium carbonate via conduit (21), and the majority of the aqueous composition is then removed from contact with the coal. The aqueous composition-treated coal is pressurized in pressure tank (16) under a carbon dioxide atmosphere for a period of time sufficient for the calcium carbonate to enter fractures in the coal produced in the first step.

Abstract: A microbiological method of desulfurization (MDS) of hydrocarbon fuels such as coal, coal tar and petroleum uses an aqueous microbial biocatalytic agent which is not significantly reproducing but is still capable of oxidizing inorganic sulfur compounds and/or of selectively cleaving sulfur-carbon bonds in organic compounds, thereby removing sulfur with insignificant losses in fuel value. Microorganisms are selected according to the type of fuel sulfur present and the environment in which the desulfurizing process is to take place. One embodiment allows droplets of highly concentrated cell-water suspensions to pass from the top surface of the fuel through to the bottom, desulfurizing along the way and removing the sulfur products of the process as well. This MDS method can be used during hydrocarbon fuel production, storage, transport, and/or processing conditions, thereby also providing an added benefit in corrosion protection of the vessels used for these functions.

Abstract: The invention provides a method treating acid raw water including the step of neutralising the water by adding calcium carbonate to it in a neutralising stage. The neutralised water is then rendered alkaline or more alkaline by adding an alkali thereto selected from calcium hydroxide, calcium oxide and mixtures thereof in a lime treatment stage. The alkaline water is then treated with carbon dioxide in a carbon dioxide treatment stage, with the carbon dioxide reacting in the carbon dioxide treatment stage with calcium hydroxide dissolved in the water.

Abstract: The present invention is, in one aspect, a process for removing low-valent sulfur from carbon containing such low-valent sulfur (sulfur-containing carbon), having the step of contacting the sulfur-containing carbon with a platinum oxide in an aqueous environment, for a time sufficient to remove a desired amount of low-valent sulfur from the sulfur-containing carbon, especially from the surface of the carbon. Another aspect of the invention is an electrode, comprising an electrocatalyst or active material for a fuel cell or battery, disposed in a carbon matrix, where the carbon matrix is essentially free of low-valent sulfur adjacent to the active material of the battery electrode or electrocatalyst of the fuel cell electrode. Such an electrode will be suitable for use in a fuel cell or in a battery. Another aspect of the invention is a fuel cell or a battery using this electrode.

Abstract: The process of demetalization and desulphuration of a mixture of carbonaceous material in an acid medium subjecting the mixture to the influence of wave energy in the microwave range, recovering, afterwards, the sulphur and separating the treated material from the rich in metal liquors.

Abstract: An aqueous, coal dust suppression fluid comprising one or more surfactants and at least one high terpene-containing natural oil. The coal dust suppression fluid can be used in a formulation of water dosed with the aqueous dust suppression fluid for the abatement of coal dust. A method is described for the abatement of coal dust using the formulation.

Abstract: An aqueous dust suspression and dewatering fluid comprising one or more surfactants and at least one high terpene-containing natural oil. The fluid can be used in a formulation of water dosed with the aqueous dust suspression and dewatering fluid for the abatement of dust and dewatering of particulate material. Methods are described for the abatement of dust and dewatering of particulate material using the formulation.

Abstract: An ultra-fine coal particle fraction forms a coal product with particles that are dilatant due to the mechanical stripping of the clay contaminates from the coal surface and the subdividing of the clay to clay platelets which are peptized to maintain discreetness in an aqueous slurry. The coal particles are unflocculated and can produce an aqueously permeable barrier on a sieve. The ultrafine coal product has an increase of 100-150 BTU per pound and when combusted reduced Nox production of 20-40% is realized. In a 15.times.0 micron coal fraction, the sulphur content is significantly reduced.

Abstract: A method for the removal of sulfur from sulfur-bearing materials such as coal and petroleum products using organophosphine and organophosphite compounds is provided.

Abstract: A method for the deep desulfurization of a liquid fossil fuel containing organic sulfur comprising aromatic sulfur-bearing heterocycles is described, wherein the fossil fuel is (a) subjected to hydrodesulfurization or microbial desulfurization, (b) contacted with a biocatalyst in an aqueous medium in an amount and under conditions sufficient for the conversion of aromatic sulfur-bearing heterocycles to inorganic sulfur, wherein the biocatalyst comprises bacteria or a substantially cell-free preparation thereof having the capability of the parent microorganism for catalyzing the removal of sulfur from aromatic sulfur-bearing heterocycles, thereby preparing a deeply desulfurized fossil fuel; and (c) separated from the aqueous medium.

Abstract: Methods and compositions are provided for treating coal to reduce the emissions of sulphur dioxide and hydrogen chloride gases upon combustion. In the subject method, coal is washed with a calcium anion wash solution, such as calcium hydroxide solution, and then separated from the wash solution. The treated coal exhibits reduced emissions of both sulphur dioxide and hydrogen chloride gas on combustion as compared with untreated coal.

Abstract: This invention relates to an integrated method for the desulfurization and desalting of a fossil fuel, comprising the steps of: (a) contacting a fossil fuel with; (i) a sufficient amount of an aqueous solution capable of depleting the fossil fuel of forms of water soluble salt contaminants; and (ii) an effective amount of a biocatalyst capable of depleting the fossil fuel of forms of sulfur-bearing organic molecules; (b) incubating the above mixture whereby; (i) the fossil fuel is significantly depleted of forms of water soluble salt contaminants; and (ii) the biocatalytic agent selectively catalyzes carbon-sulfur bonds in sulfur-bearing organic molecules generating a significant amount of water-soluble inorganic sulfur molecules; both reactions occurring without depleting the fossil fuel of combustible organic molecules; and (c) separating the aqueous component from the fossil fuel component, the fossil fuel now being significantly reduced in sulfur and salt contamination and the aqueous component now being

Abstract: First, nitrogen oxides are reduced by firing coal in substoichiometric air conditions in a first stage oxidation unit of a combustor to reduce NO.sub.x from fuel bound nitrogen. Hydrated lime, Ca(OH).sub.2, is introduced into the first stage oxidation unit to produce calcium sulfide. The calcium sulfide becomes tied up in a slag eutectic which is removed prior to entry of the fuel gas to a second stage oxidation unit at the entrance of a furnace where additional preheated air is added to the fuel gas.

Abstract: A method for the removal of sulfur from sulfur-bearing materials such as coal and petroleum products using organophosphine and organophosphite compounds is provided.

Abstract: A method of deeply desulfurizing a fossil fuel which contains a variety of organic sulfur compounds, some of which are labile to hydrodesulfurization (HDS) and some of which are refractory to HDS, comprising the steps of (a) subjecting the fossil fuel to HDS or a similar method of desulfurizing labile organic sulfur compounds, and b) subjecting the fossil fuel to biocatalytic desulfurization (BDS) using a biocatalyst which is capable of selectively liberating sulfur from HDS-refractory organic sulfur compounds. In this manner, a fossil fuel is produced which does not generate sufficient levels of hazardous, sulfur-containing combustion products that it requires post-combustion desulfurization when it is burned. Moreover, the deeply desulfurized fossil fuel can be produced using only a mild HDS treatment, rather than requiring conditions which may be severe enough to be detrimental to the fuel value of the desired product.

Abstract: The inorganic and organic desulfurization of solid carbonaceous material at elevated temperatures is increased significantly in the presence of copper. The copper serves as a scavenger for the hydrogen sulfide formed to insure a low hydrogen sulfide concentration for the inorganic desulfurization. In addition, in the presence of ethanol or hydrogen, the organic desulfurization of solid carbonaceous material is improved dramatically by the catalytic influence of the copper on the ethanol dehydrogenization and of the copper sulfide formed on the hydrodesulfurization reactions.

Abstract: This invention relates to an integrated method for the desulfurization and desalting of a fossil fuel, comprising the steps of: (a) contacting a fossil fuel with; (i) a sufficient amount of an aqueous solution capable of depleting the fossil fuel of forms of water soluble salt contaminants; and (ii) an effective amount of a biocatalyst capable of depleting the fossil fuel of forms of sulfur-bearing organic molecules; (b) incubating the above mixture whereby; (i) the fossil fuel is significantly depleted of forms of water soluble salt contaminants; and (ii) the biocatalytic agent selectively catalyzes carbon-sulfur bonds in sulfur-bearing organic molecules generating a significant amount of water-soluble inorganic sulfur molecules; both reactions occurring without depleting the fossil fuel of combustible organic molecules; and (c) separating the aqueous component from the fossil fuel component, the fossil fuel now being significantly reduced in sulfur and salt contamination and the aqueous component now being

Abstract: An aqueous, coal dust suppression fluid comprising one or more surfactants and at least one high terpene-containing natural oil. The coal dust suppression fluid can be used in a formulation of water dosed with the aqueous dust suppression fluid for the abatement of coal dust. A method is described for the abatement of coal dust using the formulation.

Abstract: A process for upgrading bitumen asphaltenes obtained from tar sands to hydrocarbons which comprises contacting the bitumen with a deasphalting solvent to yield a deasphalted oil and a residual solid asphaltene, separating the residual solid asphaltene from the deasphalted oil and treating the solid asphaltene fraction with superheated water containing a soluble carbonate salt at temperatures of from 300.degree. to 425.degree. C.

Abstract: A method for site remediation for mitigating contamination from metals or metal compounds, particularly resulting from the situation of mine tailing waste on or near water sources, including the reprocessing and redeposit of separated sands and slimes in-site in a manner to encourage rather than inhibit leaching of residuals by chelating agents or biological agents with recovery of leachate and removal of metals or metal compounds.

Abstract: A process for upgrading bitumen asphaltenes obtained from tar sands to hydrocarbons which comprises contacting the bitumen with a deasphalting solvent to yield a deasphalted oil and a residual solid asphaltene, separating the residual solid asphaltene from the deasphalted oil and treating the solid asphaltene fraction with superheated water at temperatures of from 300.degree. to 425.degree. C.

Abstract: A process for reducing the sulfur and ash content of coal. Particulate coal is introduced into a closed heated reaction chamber having an inert atmosphere to which is added 50 mole percent NaOH and 50 mole percent KOH moist caustic having a water content in the range of from about 15% by weight to about 35% by weight and in a caustic to coal weight ratio of about 5 to 1. The coal and moist caustic are kept at a temperature of about 300.degree. C. Then, water is added to the coal and caustic mixture to form an aqueous slurry, which is washed with water to remove caustic from the coal and to produce an aqueous caustic solution. Water is evaporated from the aqueous caustic solution until the water is in the range of from about 15% by weight to about 35% by weight and is reintroduced to the closed reaction chamber.

Abstract: A process for reducing the sulfur content of coal containing pyritic and organic sulfur comprising: contacting the coal with less than the molar stoichiometric amount of at least one +5 vanadium component and at least one reducible manganese component at selected conditions effective to oxidize at least a portion of the sulfur in the coal; reducing the sulfur content of the oxidized sulfur-containing coal; and recovering a coal product having a reduced sulfur content.In another embodiment, the process involves the use of certain plant derived ortho-quinone containing components, in particular, certain lignin and/or tannin derived components containing ortho-quinone functionality, to oxidize at least a portion of at least one of the pyritic and organic sulfur materials in the coal.Preferred compositions comprise at least one ligno sulfonate component containing ortho-quinone functionality.

Abstract: A process for the removal of hydrogen sulfide present in a composition comprising treating the composition with a water-in-oil emulsion wherein said water-in-oil emulsion containing by weight about: 20 to 80% of a dispersed aqueous phase containing about 20 to 70% of one or more aldehydes chosen from the group constituted by formaldehyde, glyoxal, glutaraldehyde, glycolaldehyde or glyoxylic acid and 80 to 30% of an aqueous solution containing 90 to 100% water and 10 to 0% of a buffer agent pH=5.5.+-.1.5; and 80 to 20% of a continuous oil phase containing about 90 to 99% of one or more saturated and liquid C.sub.6 -C.sub.16 hydrocarbons, and 10 to 1% of an emulsifying system constituted by one or more water-in-oil emulsifying agents.

Abstract: A process for producing enhanced quality adsorbent carbons and environmentally acceptable materials for energy production from coal includes an initial step of physically cleaning the coal to remove organic sulfur and mineral tailings. Next, a coal slurry of feedstock and water is prepared. Phosphoric acid is then mixed into the water of the coal slurry to provide by volume 15-85% and more preferably 50-85% phosphoric acid. The slurry is then heated and held in a temperature range between 85.degree. and 230.degree. C. for a period of at least five minutes to allow the phosphoric acid to penetrate deeply into the coal. Then the coal slurry is carbonized at a temperature of between 200.degree.-700.degree. C. for at least five to sixty minutes. The processing produces unique products including a low ash content, low sulfur content carbon solid, a tar with a sulfur content of less than 0.05% of the original feedstock and a gas product having a hydrogen to methane ratio of at least 4:1.

Abstract: A process of selectively agglomerating coal in an aqueous environment while leaving the mineral matter dispersed has been developed. This process is autogenous for hydrophobic particles in that neither an agglomerating agent nor an electrolytic coagulant is needed. It is based on the finding that hydrophobic particles are pushed against each other by the surrounding water structure. This process, which is referred to as selective hydrophobic coagulation, is driven by the so-called hydrophobic interaction energy, which is not included in the classical DLVO theory describing the stability of lyophobic suspensions. The relatively small coagula formed by the selective hydrophobic coagulation process can be readily separated from the dispersed mineral matter by several different techniques such as screening, elutriation, sedimentation and froth flotation.

Abstract: The use of electrostatic demulsification methods to separate fine particulates of differing surface characteristics is disclosed. In one example, particles of hydrophobic coal and hydrophilic kaolin clay, each of nominal 3.5 micron mass mean particle diameter, were separated from a variety of stable water-in-oil emulsions. 50/50 blends of coal of 4% ash and kaolin clay of 86.5% ash were used in the experiments. A variety of oils, water concentrations, solids concentrations, and emulsifiers have been used in this work. Externally applied electrostatic fields up to 1.2 kV/cm were used. Greater than 90% rejection of kaolin particles into the separated water phase was achieved with virtually complete recovery of the coal particles uniformly suspended in the oil phase.

Abstract: In a process for reducing the sulfur and ash contents of coal, coal is sequentially contacted with fused alkali metal caustic, wash water, and acid. Contacting the coal with the caustic produces water-soluble compounds. Sufficient wash water is used to reduce the temperature of the caustic treated coal and dissolve the bulk of the water-soluble compounds before the water-soluble compounds convert to water-insoluble compounds that precipitate on the caustic-treated coal. Caustic removed from the coal by the water is recovered as anhydrous caustic for again contacting coal.

Abstract: A method of chemically comminuting a low-rank coal while at the same time increasing the heating value of the coal. A strong alkali solution is added to a low-rank coal to solubilize the carbonaceous portion of the coal, leaving behind the noncarbonaceous mineral matter portion. The solubilized coal is precipitated from solution by a multivalent cation, preferably calcium.