The present invention relates to a method for determining oxidation of coal, the method comprising: a) mixing a coal sample with an organic solvent and an inorganic solvent, to extract oxidised coal species from the coal sample into a liquid phase, and b) analysing the liquid phase from step (a) to determine a degree of coal oxidation. The inorganic solvent may comprise an inorganic compound such as a pyrophosphate. The present invention also relates to a method for controlling collector used in a coal flotation process, the method comprising determining a degree of oxidation of coal by the preceding method and controlling a ratio of non-polar collector to polar collector in the coal flotation process in response to the determined degree of oxidation of coal.

Methods of increasing the rate of separating hydrophobic and hydrophilic particles by flotation have been developed. They are based on using appropriate reagents to enhance the hydrophobicity of the particles to be floated, so that they can be more readily collected by the air bubbles used in flotation. The hydrophobicity-enhancing reagents include low HLB surfactants, naturally occurring lipids, modified lipids, and hydrophobic polymers. These methods can greatly increase the rate of flotation for the particles that are usually difficult to float, such as ultrafine particles, coarse particles, middlings, and the particles that do not readily float in the water containing large amounts of ions derived from the particles. In addition, new collectos for the flotation of phosphate minerals are disclosed.

Processes for upgrading of a coal product and preparing of a purified coal product are provided. The process comprises the steps of: (i) providing a purified coal composition, wherein the composition is in the form of solid particles, and wherein at least about 90% by volume (% vol) of the solid particles are no greater than about 500 ?m in diameter; and (ii) combining the purified coal composition with a solid coal feedstock, in order to create a combined solid-solid blend upgraded coal product.

A separation system is disclosed for separating selected particles from a mixture of particles in a fluid. The system includes a froth flotation vessel 10 into which in use the mixture of particles and fluid are subjected to an upward flow of an introduced gas to form a froth layer 13 which rises above an interface 14 formed between the froth layer 13 and the mixture of particles and fluid 12, such that a quantity of the selected particles is conveyed out of the vessel 10 by the froth layer 13 to become a first product of the system. The vessel 10 also has a first outlet 29 arranged in use for receiving a flow of some of the mixture of particles and fluid from the vessel 10, an entry to the first outlet 29 being located in a region proximate to, but below, the interface 14. The vessel also has a second outlet 20 arranged in use for receiving a flow of some of the mixture of particles and fluid from a region of the vessel 10 which is located below the first outlet 29. In use the first outlet 29 receives a quantity of the selected particles which were not conveyed out of the vessel by the froth layer 13, and the second outlet 20 receives a quantity of the selected particles in a first by-product of the system. The first by-product comprises a relatively higher percentage of solids compared to the flow of particles and fluid in the first outlet 29. The flow of the mixture of particles and fluid from the vessel 10 via the first outlet 29 passes to a classification device 31, 76 which separates the flow into two or more fractions on the basis of their size or density or a combination of the two.

The coal-derived solid hydrocarbon particles are discrete particles of coal-derived carbonaceous matter having a particle size less than about 10 m that are substantially free of inherent or entrained mineral matter. The particles of have an average particle size in the range from 1 m to 8 m. The particles of coal-derived carbonaceous matter are milled to a size approximately the same as a size of coal-derived mineral matter inherent in the coal source to release inherent coal-derived mineral matter particles such that the particles of carbonaceous matter and the particles of mineral matter are discrete and separable solid particles. Following separation, less than 1.5 wt. % discrete coal-derived mineral matter particles are associated with the discrete particles of coal-derived carbonaceous matter. Particles of coal-derived solid hydrocarbon matter are blended with a gaseous or liquid hydrocarbon fuel to form a two-phase hydrocarbon fuel feedstock.

The subject invention provides safe, environmentally-friendly, compositions and methods for extracting minerals and/or metals from rock, ore, tailings, and/or coal combustion wastes. More specifically, the subject invention provides for enhanced froth flotation, including direct flotation or reverse flotation, of rock, ore, tailings, and/or coal fly ash using a composition comprising one or more biosurfactants.

A process is developed wherein sodium carbonate is reclaimed from Trona-treated fly ash waste stream, and the fly ash rendered suitable for use as a Pozzolan. The process is a closed system wherein all separated aspects of the waste stream are reused by the generating power plant or offered as a commercial product.

Coal fines are processed by flotation separation to separate coal particles from ash-forming mineral content particles. Coal fines are mixed water under high shear mixing conditions to form an aqueous slurry of coal fines containing between 15 wt. % and 55 wt. % coal fines. The aqueous slurry is introduced into a coal flotation cell to separate coal particles from ash-forming mineral content particles by flotation separation, wherein the coal fines have a particle size less than 100 m, and more preferably less than 50 m. Bubbles are generated in the coal flotation cell having a bubble size and bubble quantity selected to float the coal particles and to form a coal-froth containing at least 15 wt. % solid particles. The solid particles include coal particles and ash-forming mineral content particles. The coal-froth is collected for further processing.

The invention provides methods and compositions for improving a froth flotation type separation. The method uses a microemulsion to improve the effectiveness of a frother. The improvement allows for low dosages of frother to work as well as much greater amounts of non-microemulsified frother.

The presently claimed invention relates to a process for the beneficiation of coal and other hydrophobic materials, wherein a collector composition comprising by-products obtained by hydroformylation of octene isomers as a first component and diesel, kerosene and/or C.sub.8-C.sub.20 olefins as a second component is used.