Abstract: An improved process for reducing sulfur oxide emissions from the combustion of coal is disclosed wherein a fuel mixture comprising calcium-containing sorbent and coal is fed to the burners and sulfur oxides react with calcium from the sorbent in a high temperature sulfur capture region, followed by additional sulfur capture in a lower temperature, high humidity sulfur capture region prior to separation of particulates from the flue gas. Sulfur capture using calcium-containing sorbents can be combined with aggressive coal beneficiation techniques to further enhance reduction of sulfur oxide emissions. The process of the invention provides a process for reducing sulfur oxides that efficiently uses calcium-containing sorbents to enhance sulfur capture while reducing the need for expensive equipment or process modifications.

Abstract: Fine particle coal is beneficiated in specially designed dense medium cyclones to improve particle acceleration and enhance separation efficiency. Raw coal feed is first sized to remove fine coal particles. The coarse fraction is then separated into clean coal, middlings, and refuse. Middlings are comminuted for beneficiation with the fine fraction. The fine fraction is deslimed in a countercurrent cyclone circuit and then separated as multiple fractions of different size specifications in dense medium cyclones. The dense medium contains ultra-fine magnetite particles of a narrow size distribution which aid separation and improves magnetite recovery. Magnetite is recovered from each separated fraction independently, with non-magnetic effluent water from one fraction diluting feed to a smaller-size fraction, and improving both overall coal and magnetite recovery.

Abstract: Fine particle coal is beneficiated in specially designed dense medium cyclones to improve particle acceleration and enhance separation efficiency. Raw coal feed is first sized to remove fine coal particles. The coarse fraction is then separated into clean coal, middlings, and refuse. Middlings are comminuted for beneficiation with the fine fraction. The fine fraction is deslimed in a countercurrent cyclone circuit and then separated as multiple fractions of different size specifications in dense medium cyclones. The dense medium contains ultra-fine magnetite particles of a narrow size distribution which aid separation and improves magnetite recovery. Magnetite is recovered from each separated fraction independently, with non-magnetic effluent water from one fraction diluting feed to a smaller-size fraction, and improving both overall coal and magnetite recovery.

Abstract: The present invention is further directed towards a method for determining the efficiency of separation of a dense media separation process. This method includes determining an apparent distance a particle must travel in a dense media cyclone to be correctly beneficiated. From this apparent distance, an apparent velocity a particle must achieve to be correctly beneficiated is calculated. This apparent velocity is used, along with cyclone geometry and operational parameters to calculate a divergence value which indicates the efficiency of separation. The present invention also includes a method for selecting cyclone geometry and operating parameters which includes determining separation efficiency and adjusting geometry and parameters in a manner to obtain improved efficiency.

Abstract: Fine particle coal is beneficiated in specially designed dense medium cyclones to improve particle acceleration and enhance separation efficiency. Raw coal feed is first sized to remove fine coal particles. The coarse fraction is then separated into clean coal, middlings, and refuse. Middlings are comminuted for beneficiation with the fine fraction. The fine fraction is deslimed in a countercurrent cyclone circuit and then separated as multiple fractions of different size specifications in dense medium cyclones. The dense medium contains ultra-fine magnetite particles of a narrow size distribution which aid separation and improves magnetite recovery. Magnetite is recovered from each separated fraction independently, with non-magnetic effluent water from one fraction diluting feed to a smaller-size fraction, and improving both overall coal and magnetite recovery.

Abstract: The present invention provides a method for selecting magnetite to form a dense media for beneficiation of fine particulate solids such that the particulate solids are as buoyant with respect to the dense media as if the solids were in a true liquid having a specific gravity equal to that of the dense media. The method involves determining a magnetite particle diameter such that the diameter ratio of particulate solid to magnetite lies above a diameter ratio partition curve. The invention is also directed toward using magnetite having a particle diameter less than about 0.005 mm and a mean particle diameter of about 0.0025 mm. Such magnetite is formed from a gas phase pyrohydrolysis reaction on an aqueous iron (ferrous) chloride solution. The present invention is further directed towards a method for determining the efficiency of separation of a dense media separation process. This method includes determining an apparent distance a particle must travel in a dense media cyclone to be correctly beneficiated.

Abstract: A method for determining the efficiency of separation of a dense media separation process is disclosed including determining an apparent distance a particle must travel to be correctly beneficiated and calculation of an apparent velocity for correct beneficiation. Apparent velocity, cyclone geometry, and operating parameters are used to calculate a divergence value which indicates the efficiency of separation. Cyclone geometry and operating parameters may be selected for use in a dense media separation process by adjusting geometry and operating parameters in a manner to obtain desired efficiency.

Abstract: The present invention provides a method for selecting magnetite to form a dense media for beneficiation of fine particulate solids such that the particulate solids are as buoyant with respect to the dense media as if the solids were in a true liquid having a specific gravity equal to that of the dense media. The method involves determining a magnetite particle diameter such that the diameter ratio of particulate solid to magnetite lies above a diameter ratio partition curve. The invention is also directed toward using magnetite having a particle diameter less than about 0.005 mm and a mean particle diameter of about 0.0025 mm. Such magnetite is formed from a gas phase pyrohydrolysis reaction on an aqueous iron (ferrous) chloride solution. The present invention is further directed towards a method for determining the efficiency of separation of a dense media separation process. This method includes determining an apparent distance a particle must travel in a dense media cyclone to be correctly beneficiated.

Abstract: A method and composition are provided for decreasing emissions of sulfur oxides and nitrogen oxides upon combustion of carbonaceous fuel material. In particular, the composition comprises a refined coal, having low ash-forming material and inorganic sulfur content, a sulfur sorbent, a sulfation promoter, and a catalyst for the reaction of sulfur dioxide to sulfur trioxide. Reduced emissions of sulfur oxides are achieved by combusting the composition in an oxygen restricted burner to lessen the effect of sorbent sintering while obtaining other advantages associated with mixing a sulfur sorbent with the carbonaceous material prior to combustion. Nitrogen oxides emissions are reduced by use of an oxygen restricted burner which lowers the flame temperature. Nitrogen oxides emissions are also reduced by lower flame temperatures resulting from endothermic reactions which are undergone by the sulfur sorbent and promoter.

Abstract: A process for substantially reducing the amount of insoluble fluoride-forming species in a coal feed material comprising slurrying a coal feed with a fluoride acid in the presence of an amount of fluoride-complexing species at least equal to the amount necessary to form tightly-bound complex ions with substantially all free-fluoride-ions in the slurry to produce a leached coal product and a spent leach liquor, and separating the leached coal product from the spent leach liquor. The process produces a clean purified fuel with ash content of less than about 5%, and preferably less than about 1%. Loss of fluorine values by formation of insoluble fluorides is minimized. Alkali metals and alkaline earths are substantially dissolved.

Abstract: This invention discloses processes for the treatment of coal and coal derivatives in order to remove contaminates to produce a high purity coal product. The processes generally comprise a sequential acid leaching in which a hydrofluoric acid leach is followed by a hydrochloric acid leach. The pyrite and other heavy metals from the coal are removed by physical separation, either gravity or magnetic separation. The leached coal is then treated either by a washing and drying step or by a heat treatment to remove volatile halides. The HF acid and the HCl acid leachates are recovered for regeneration of the respective leachates and are recycled for use in the leaching steps. In additional processing, the coal may be pre-treated by a mild HCl acid leach and by pre-drying or physical beneficiation of the coal feedstock.

Abstract: The present invention provides processes for the continuous removal of contaminants from coal to produce a clean purified fuel. The processes generally comprise producing a clean coal product having a mineral matter content of less than about 5 percent by weight from coal and coal derivatives by leaching feed coal crushed or sized to less than about 1 inch with a mixture of hydrochloric and hydrofluoric acids comprising less than about 70 weight percent HF and less than about 38 weight percent HCl at atmospheric pressure and at a temperature below the boiling point of the acid mixture.

Abstract: One or more mineral values of sulfide ores are beneficiated by cotreating the sulfide ore with a metal containing compound and a reducing gas under conditions such as to selectively enhance the magnetic susceptibility of the mineral values to the exclusion of the gangue in order to permit a physical separation between the values and gangue.

Abstract: In a process for beneficiating one or more mineral values of sulfide ores by treating the sulfide ore with a metal containing compound under conditions such as to selectively enhance the magnetic susceptibility of the mineral values to the exclusion of the gangue in order to permit a separation between the values and gangue, the improvement comprising pretreating the sulfide ore by heating it to a temperature of at least about 80.degree. C. for at least about 0.1 hours.

Abstract: In a process for beneficiating one or more mineral values of sulfide ores and/or metal oxide ores selected from the group consisting of bauxite, taconite, apatite, titanium oxides and the metal oxides of Groups IIIB, IVB, VB, VIB, VIIB, VIIIB, IB, IIB and IVA by treating the ore with a metal containing compound under conditions such as to selectively enhance the magnetic susceptibility of the mineral values to the exclusion of the gangue in order to permit a separation between the values and gangue, the improvement comprising removing at least a portion of any elemental sulfur present from the ore prior to the treatment with a metal containing compound.

Abstract: One or more mineral values of metal oxide ores selected from the group consisting of bauxite, taconite, apatite, titanium oxides and the metal oxides of Groups, IIIB, IVB, VB VIB, VIIB, VIIIB, IB, IIB and IVA are beneficiated by treating the ore with a metal containing compound under conditions such as to selectively enhance the magnetic susceptibility of the mineral values to the exclusion of the gangue in order to permit a physical separation between the values and gague.

Abstract: One or more mineral values of sulfide ores are beneficiated by treating the sulfide ore with a metal containing compound under conditions such as to selectively enhance the magnetic susceptibility of the mineral values to the exclusion of the gangue in order to permit a physical seaparation between the values and gangue.

Abstract: A process for beneficiating particulate gold from non-magnetic foreign material with which it is mixed which comprises contacting the mixture with an iron carbonyl in order to selectively enhance the magnetic susceptibility of the gold particles so that a magnetic separation between the gold and foreign material may be effected.

Abstract: In a process for beneficiating one or more mineral values of a metal oxide ore selected from the group consisting of bauxite, taconite, chrysocolla, apatite, titanium oxides and the metal oxides of Groups IIIB, IVB, VB, VIB, VIIB, VIIIB, IB, IIB and IVA by treating the ore with a metal containing compound, preferably iron carbonyl, under conditions such as to selectively enhance the magnetic susceptibility of the mineral values to the exclusion of the gangue in order to permit a separation between the values and gangue, the improvement comprising pretreating the metal oxide ore by heating it to a temperature of at least about 80.degree. C. for a time period of at least about 0.1 hours.

Abstract: Raw coal is improved by reacting it with a metal containing compound selected from the group consisting of organic iron containing compounds which exert sufficient vapor pressure, with iron as a component in the vapor, so as to bring the iron into contact with the impurity at the reaction temperature, organic iron containing compounds in solution at the injection temperature, solid organic iron containing compounds capable of being directly mixed in solid form at the mixing temperature with the coal, and ferrous chloride, ferric chloride, and alkyl aluminum compounds, in order to enhance the magnetic susceptibility of certain impurities, e.g., pyrite and ash-forming minerals contained in the raw coal, thereby permitting the removal of these impurities by magnetic means.