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: 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.