Apparatus and methods for a mixing device are presented. The mixing device comprises a shaft and a plurality of blades attached to the shaft. The blades include a variable pitch angle configured to create axial fluid flow and radial fluid flow within a container. The apparatus includes a hub and a cage located at ends of the apparatus. The cage includes an open end configured to mate with a structure attached to the container. In further examples of the apparatus, the upper blade is configured to create axial flow in a substantially downward direction. The lower blade is configured to create axial flow in a substantially upward direction. The lower blade can create an axial flow that encounters the upper blade. A method includes locating a mixing apparatus within the container, inserting fluid within the container, rotating the mixing apparatus, and mixing the fluid.

Mixer apparatus configured to mix the contents of a vessel without the formation of a vortex are provided. The mixer apparatus can include a rotational mechanism; a gearbox attached to the rotational mechanism; a first shaft attached to the gearbox; a second shaft attached to the gearbox; a first rotor configured to be rotated by the first shaft; and a second rotor configured to be rotated by the second shaft. The first shaft can be coaxial with the second shaft, and the gearbox can be configured to rotate the first shaft and the second shaft in opposite directions. The first rotor and the second rotor are configured to be rotated in opposite directions.

An apparatus and method for mixing a liquid having particulate includes a vessel for containing me liquid an axial impeller rotating about a substantially vertical axis. The impeller is adapted for submerging below the liquid surface by a distance approximately one-quarter to one-half of the height of the liquid. The impeller is oriented upwardly to produce (a) an inner, upward flow region located along the vertical axis of the vessel, (b) a transition flow region above the impeller in which liquid moves radially outwardly toward the vessel sidewall, and (c) an outer, downward flow region located along the sidewall. The impeller spins at a variable speed, such that the flow is capable of entraining solid particles having a settling velocity of up to approximately 1 foot per minute in the liquid, and the speed of the impeller is chosen to enable particles having a desired settling velocity to settle to the vessel bottom.

A hydrofoil impeller wherein the tip edge is straight and has a right angle with a radius extending from the central axis to the tip edge. In the central hub and in each of the blades the number of holes in each group of first and second holes is at least five. The pattern in which the holes are arranged in each of the respective groups of holes is elliptical having a center and a major axis which is substantially parallel to the radius and placed at a distance therefrom. The leading edge is, in the direction to rotation, behind an imaginary radial line intersecting the central axis of the shaft and the center of the ellipse, said leading edge being at an angle of 58°±2° in relation to the radial line. The area of the blade is divided into four planar portions by three straight bends.

A fluid holding structure fluid circulating system includes a fluid movement assembly with a propeller including a housing having a perimeter wall and a plurality of blades attached to an outer surface of the perimeter wall. A motor is mechanically coupled to the propeller and is positioned above the propeller. A buoy has buoyancy in fluid great enough to raise the fluid movement assembly adjacent to a surface of a fluid holding structure when the motor is turned off. The motor is mounted within the buoy and the propeller urges fluid upwardly toward the buoy when the motor is turned on to rotate the propeller. The propeller is completely exposed around its lateral periphery. A positioning cable is attached to the fluid movement assembly to facilitate movement thereof within the fluid holding structure.

Attrition mills and propeller shaft assemblies therefor are described having features for enhanced installation and maintenance. Some embodiments include propellers having enhanced material processing characteristics.

A mixing tank is disclosed for reducing ingestion across an interface. The tank may include a first zone including most of the volume of the tank; a second zone including the interface; a source of mixing energy configured to provide a first bulk energy dissipation rate in the first zone; a divider located between said first zone and said second zone inhibiting transfer of said mixing energy from said first zone to said second zone to preserve in said second zone a bulk power dissipation level less than a said first bulk power dissipation level; and a mass transport passageway between said first zone and said second zone for preserving a uniformity between the first and second zones. A method is disclosed for manufacturing a mixing tank and for retrofitting and existing mixing tank and for managing mixing to prevent air ingestion.

A mixing apparatus for mixing particles in a liquid and its use are disclosed. The mixing apparatus comprises a tank having a bottom and a substantially vertical side wall, an agitation means comprising a rotation shaft located vertically and centrally in the tank, and an impeller arranged at a height above the bottom at the end of the rotation shaft and the impeller being a downward pumping axial or mixed flow impeller. The bottom is equipped with a corrugated formation comprising alternate consecutive ridges and valleys, the ridges and valleys extending radially in relation to a center of the bottom, whereby the valleys concentrate and channel the mixing power near to the bottom to direct the flow of the liquid and to increase the velocity of the flow near to the bottom.

The present invention relates to a method for flocculating and dewatering oil sands fine tailings. Said method comprises mixing the aqueous mineral suspension with a poly(ethylene oxide) (co)polymer to form a dough-like material. The material is then dynamically mixed in an in-line reactor to break down the dough-like material to form microflocs having an average size of 1 to 500 microns, and to release water. The internal diameter of the in-line reactor is at most five times the internal diameter of the inlet pipe of the reactor. The suspension of microflocs has a viscosity of at most 1000 cP and a yield stress of at most 300 Pa.

A stirrer having a motor; a hollow shaft that is drivable via the motor and is provided with at least one additive outlet opening, via which an additive passed through the hollow shaft can be discharged; and a rotor arranged on the hollow shaft and having rotor blades, characterized in that a second rotor having rotor blades is provided on the hollow shaft at a distance from the first rotor, and in that the at least one additive outlet opening is provided between the two rotors, wherein the rotors are designed and drivable such that, during operation, a negative pressure and a centrifugal force are generated in the intermediate space defined between the rotors.