Abstract: The present invention provides a method for separation of fine particles in a bimodal (two component) dense medium. In accordance with the present invention, the dense medium comprises ferromagnetic particles that have a relative density range from about 4.0 to 7.0 suspended in water and are characterized by a bimodal size distribution. Such a medium exhibits high stability and favourable rheological properties. The use of such a bimodal magnetite dense medium in cleaning fine coal in a dense medium cyclone or dynamic dense medium separator results in optimum separation efficiency when the medium contains approximately 20-40% fine and 60-80% coarse magnetite, and when the size ratio of coarse-to-fine magnetite is in the range of 5 to 10.

Abstract: A composition, adapted to be used in the beneficiation of coarse potash ore fractions in the substantial absence of extender oil, which consists essentially of: (a) water; and (b) a long chain primary aliphatic amine, for example, a tallow-based amine, having an iodine value of from about 20 to about 70 cg/g, preferably from about 40 to about 60 cg/g. The composition may further contain an acid to assist in the dispersion of the amine in water.

Abstract: A composition, adapted to be used in the flotation of ore fractions in aqueous suspension, with the advantages of better dispersability of the amine and improved flotation results. The composition consists essentially of: (a) water; (b) a long chain aliphatic amine; and (c) a frother. The composition may further contain a carboxylic or mineral acid emulsifier.

Abstract: A composition, adapted to be used in the flotation of ore fractions in aqueous suspension, consists essentially of: (a) water; (b) a hydrocarbon extender oil, preferably one having a low aromatics content; (c) a long chain aliphatic amine, such as a tallow-based amine, preferably one with an iodine value is less than about 20 cg/g; and (d) an acid emulsifier. This composition is prepared by the following successive steps: (a) dissolution of the amine in the oil at an elevated temperature, (b) addition of the acid to the aqueous phase, (c) addition of the oil containing the amine to the aqueous phase, and (d) emulsification of the mixture using an appropriate shearing.

Abstract: A process for the flotation of coarse potash ore fractions in an aqueous brine containing frother that comprises: (a) using a column flotation device in which air bubbles are generated by a sparger that utilizes high intensity shearing to mix and disperse air into brine containing frother; (b) removing a portion of the suspension at another point in the direction of flow of the suspension to regulate the upward flow rate of the suspension past the point where the air is dispersed into the suspension and thereby reducing fine particles entrainment in the froth product. The suspension can be conditioned with an aqueous composition comprising a hydrocarbon extender oil and a substantially saturated long chain primary mine, optionally comprising an acid, such as a mineral acid or carboxylic acid, to emulsify the oil in the composition, or can be conditioned with an aqueous composition comprising a long chain primary amine having an iodine value ranging from about 20 to about 70 cg/g.

Abstract: This invention relates to an apparatus for determining the rheological properties of sedimenting suspensions. More particularly, this invention relates to a method and apparatus which permits the accurate determination of the rheological properties of particulate suspensions in which the particles are settling. An apparatus for evaluating the rheological properties of sedimenting suspensions comprising: (a) a sedimenting suspension retainer; (b) a device means suspended in the retainer, the retainer and suspended device being capable of being rotated relative to one another, the device being permeable to the passage of particles settling in the sedimenting suspension, the suspended device being suspended in the sedimenting suspension in the retainer in the region having constant density.