Abstract: A method and apparatus are disclosed for the microbubble flotation separation of very fine and coarse particles, especially coal and minerals, so as to produce high purity and high recovery efficiency. This is accomplished through the use of a flotation column, microbubbles, recycling of the flotation pulp, and countercurrent wash water to gently wash the froth. Also disclosed are unique processes and apparatus for generating microbubbles for flotation in a highly efficient and inexpensive manner using either a porous tube or in-line static generators.

Abstract: The present invention provides a process that employs both non-selective flotation and oxidative leaching of the resulting concentrates to recover an increased amount of copper from porphyry copper ores. The non-selective flotation step uses collectors and conditions, such as pH, that are conducive to the strong flotation of sulfide minerals generally. In the oxidative leach, the copper sulfide minerals in the concentrate fraction are oxidized to copper compounds, which are soluble in the leach solution. The oxidative leach includes the use of ammonia and sulfite under agitation leaching conditions to convert the copper sulfide minerals into ammonia soluble forms.

Abstract: A mixture of air and paper stock made from recycled paper from which the ink particles have been chemically released is injected into a cylindrical processing vessel. Added surfactants create a foam from the air as it rises through the stock and cause the ink particles to adhere to the air bubbles, resulting in a foam containing a concentrated fraction of the ink particles with some included fibers. The foam rises to the top of the vessel, and carries with it ink particles. Additional air injection ports can be used to increase the amount of foam generated and the amount of ink removed. Flow of stock and foam from the vessel can be controlled by adjusting valves on the stock and foam outlets. Flotation sensors allow the foam head to be maintained at the stock level by controlling the rate foam is withdrawn through the foam outlets.

Abstract: An apparatus for selective particle flotation includes a static mixer connected to a flotation section in lieu thereof of the apparatus. The static mixer is disposed upstream of the flotation section in lieu thereof with respect to a direction of fluid flow through the apparatus. The static mixer mixes sludge with small gas bubbles. A flotation cyclone is disposed in an upstream portion of the flotation section in lieu thereof with respect to the direction of fluid flow through the apparatus. The flotation cyclone is the initial separation device through which the sludge flows.

Abstract: A pressure screening system for processing contaminated pulp fiber including a pressure screen apparatus for separating an accepts stream of clean fiber from a rejects stream carrying contaminants, and a feed tank for supplying a pulp fiber slurry to the inlet of the pressure screen apparatus, wherein the feed tank has a flotation section for receiving the rejects stream together with air for generating a froth separating a rejects overflow of contaminants from the remainder of the feed stock for recovery of additional pulp fiber from the rejects stream. The air may be contained in the rejects stream when it enters the flotation section, or it may be introduced at or near the input to the flotation section. The feed tank with flotation section can receive the rejects streams from multiple pressure screen stages, or a separate feed tank can be used for each pressure screen stage.

Abstract: A flotation apparatus including: an elongate vertical riser (142) in which a cocurrent flow of gas/slurry liquid mixture rises upwards to a discharge mouth at its top end; an aeration unit (140) provided at a lower end of the riser; a separation unit (150) provided at the top end of the riser; and wherein the height of the riser is selected to produce substantially turbulence free flow in which a high gas lift occurs in the riser such that a pressure drop between the liquid inlet and the discharge outlet of the aeration unit is sufficient to produce gas particle dispersion and recirculation of the slurry liquid through the flotation apparatus.

Abstract: A novel apparatus for use in frothless flotation. The apparatus includes a cover which is sealingly engaged to the top of the flotation column and a wash-water tank in communication with the upper part of the flotation column wherein the level in the wash-water tank is maintained at or above the level of the cover thereby preventing the formation of a froth layer in the column. The apparatus is adapted to recycle the pulp and the tails. Gas is introduced to the feed and/or recycled tails in motionless mixers. Bubble-pulp separators are provided which recirculate pulp to enhance the quality of the yield.

Abstract: A process for cleaning recycled pulp includes an upright cylindrical vessel having an upright cylindrical screen member open at its top and bottom ends and having a perforated screen wall which is centered on a vertical axis in the vessel. A plurality of upright, elongated blades are mounted for rotation on the vertical axis in close proximity to the screen wall. A pulp slurry entrained with pressurized air is introduced under pressure into an inlet in the bottom of the vessel. The rotating blades clear the screen wall while creating a rising vortex of air bubbles produced by the pressurized air for carrying ink and/or contaminant particles upwardly through the inner volume of the screen member. An "accepts" outlet at the center of the vessel draws off pulp in suspension that has been passed through the screen wall. A "rejects" outlet at the top of the vessel draws off ink and contaminant particles carried by the air bubbles in the upwardly-moving vortex.

Abstract: A flotation method and apparatus for separating a selected constituent from an effluent of an industrial process is provided. The apparatus includes a conditioning tank and a flotation cell. The conditioning tank allows mixing a flotation reagent with an effluent and includes a mechanism for also dissolving gas in the effluent within the conditioning tank. The flotation cell includes a dissolved gas flotation chamber having an overflow for recovering the selected constituent and a tailings drain. In addition, the flotation cell also includes an added gas flotation chamber having a sparger for injecting gas into the effluent, an overflow for recovering the selected constituent and a tailings drain.

Abstract: Process and apparatus for the separation of solid matter via flotation. The flotation process for the separation of solid matter from a suspension takes place via the utilization of centrifugal forces wherein the suspension is brought into rotation in a separating zone so that the floated components are particularly effectively routed to and concentrated at the center of the separating space, whereby, when viewed axially, floated components and the remaining portion of the suspension is guided in the same direction and out of the separating zone, with the avoidance of vortexes in the flow stream achieving particularly favorable separation effects. In addition, several apparatuses, for carrying out the process, are also set forth.

Abstract: A sparging system assembly having an improved nozzle for use in a flotation separation column. The sparging system of the present invention uses an elastomeric check valve type nozzle to form the desired size of flotation bubbles in the column. The system further comprises an installation configuration and valving arrangement for the easy, efficient replacement of any worn or damaged elastomeric check valve type nozzle during the operation of the flotation separation column.

Abstract: A method and apparatus for separating particulate material. The method includes the steps of delivering a substantially constant supply of feed to a first aerator, aerating the substantially constant supply of feed in the first aerator, introducing the substantially constant supply of aerated feed to a flotation vessel below a froth/liquid interface within the vessel, so that floatable particulate material entrained by air bubbles from the first aerator can float upwardly to the froth/liquid interface. Air is introduced into the liquid phase in the flotation vessel via a second aerator located below the level at which the aerated feed is introduced into the flotation vessel, so that floatable particulate material not entrained by air bubbles from the first aerator, may be entrained by air bubbles from the second aerator, as the air bubbles from the second aerator rise upwardly through the liquid phase to the froth/liquid interface.

Abstract: A suitably conditioned slurry feed is introduced to a trough from which it is distributed into a slurry layer-flow forming chamber provided with a discharge weir which discharges an evenly spread layer of slurry onto an inclined plate feeding into a mixing passage and then into a vessel. Recirculated slurry from the vessel is also fed into the mixing passage via a recycle gate which forms it into a layer of slurry. An array of clean liquid jets accelerates thin gas envelopes and impinges between layers of slurry and causes intensive mixing of all streams in the mixing passage. A high shear rate produces high intensity turbulence and shears gas into very small bubbles. A multiphase mixture flow is discharged from the mixing passage into the vessel, where it flows past one or more longitudinal stabilizing baffles. Gas bubbles loaded with hydrophobic particles disengage from the stream, rise toward the liquid surface and are diverted by bubble-diverting guides toward a froth discharge end of the vessel.

Abstract: The cell 1 includes an upper cylindrical chamber 2 comprising at its center over its entire height a vertical ink removal pipe 4. A lower lateral pipe 9 receives via an opening 10 a paper pulp feed diluted in water and is fed with air from an upper pipe 12. Injectors placed on the pipe 9 inject the paper pulp and air into the chamber 2. Each injector has the shape of a tube with a constant diameter and opens at its outlet extremity through about twelve honeycomb-shaped orifices, thus ensuring a satisfactory dispersion of the air. The air bubbles lift up the ink particles so as to form a foam evacuated by the pipe 4.

Abstract: A method for deinking paper pulp, wherein the batch of pulp to be deinked is made to circulate to move from top to bottom whereas the air bubbles are introduced at least in the lower part and move from bottom to top, characterized in that the pulp descends from top to bottom while being recycled in several consecutive and superposed stages.

Abstract: An air injector for the foaming of paper pulp, comprised of a hollow cylindrical tube inside which is arranged a cylindrical bore (3) leading into a convergent portion and a divergent portion (2a, 2b, 2c), said cylindrical bore being occluded by a stopper fitted with holes (8) providing a cylindrical air inlet chamber (3a).

Abstract: A method of gas particle formation in a liquid medium comprising the steps of: forming a substantially continuous film of gas on a surface having a discharge edge submerged in the liquid medium; generating a flow of liquid over the surface, adjacent to and co-current with the film of gas, directed towards the discharge edge; and breaking the gas film into gas particles by shear forces as it approaches and/or escapes from the discharge edge.

Abstract: Flotation apparatus (10) for removing finely divided bodies of an insoluble substance dispersed in an aqueous medium, such as oil and solids dispersed in water, comprises a vertical flotation column (12) having a feed inlet (14) and an outlet (22) for the aqueous medium, a sparging system (16) for generating gas bubbles rising upwardly in the aqueous medium to capture and raise the finely divided bodies of the insoluble substance to the surface of the aqueous medium in the column to form a layer (31) of the insoluble substance on the surface of the aqueous medium, a launder (18) for receiving an overflow of the insoluble substance and an outlet (20) for the insoluble substance in the launder. The apparatus (10) can be used in both countercurrent and co-current fashion. In a particular embodiment, the apparatus includes a mechanism for the intermittent dumping of the layer (31) of insoluble substance from the column (12).

Abstract: An apparatus for cleaning recycled pulp includes an upright cylindrical vessel having an upright cylindrical screen member open at its top and bottom ends and having a perforated screen wall which is centered on a vertical axis in the vessel. A plurality of upright, elongated blades are mounted for rotation on the vertical axis in close proximity to the screen wall. A pulp slurry entrained with pressurized air is introduced under pressure into an inlet in the bottom of the vessel. The rotating blades clear the screen wall while creating a rising vortex of air bubbles produced by the pressurized air for carrying ink and/or contaminant particles upwardly through the inner volume of the screen member. An "accepts" outlet at the center of the vessel draws off pulp in suspension that has been passed through the screen wall. A "rejects" outlet at the top of the vessel draws off ink and contaminant particles carried by the air bubbles in the upwardly-moving vortex.

Abstract: The present invention concerns a reactor for removing impurities from a liquid, in particular for de-inking, including a tank (1) within which the liquid to be purified together with a gas or air is introduced (2-3); a drain of the purified accepted through an outlet (7) of said tank (1); inlets (8-11, 9-12, 10-13) at different heights of the tank (1) connected to said purified liquid outlet (7) together with the inlet of gas or air; a rotating shaft (18) inside the tank (1) carrying blades (20, 21, 22, 23) at the different heights of the tank within which the liquid together with gas or air is introduced; the blades (20, 21, 22, 23) have progressively increasing heights when moving towards the lower portion of the tank (1). The invention also concerns the method embodied by the above-described reactor.

Abstract: A conventional gas-sparged hydrocyclone, including a plug that cooperates with an interior surface of the hydrocyclone to adjust the size of an orifice defined adjacent the suspension outlet, is mechanically adjusted. The plug position is adjusted by a mechanical device from a position exteriorly of the hollow body while the hydrocyclone is running with suspension fed to its inlet, to effect direct linear movement of the plug with respect to the body interior surface. The mechanical elements include first and second pins and links within the hydrocyclone, a shaft having a drive portion extending exteriorly of the hydrocyclone, and a manually actuated link assembly or stepper motor for rotating the shaft. The manual actuator may be associated with an indexing arrangement to positively hold the plug at the position to which it has been adjusted.

Abstract: A method for the separation of components of a slurry by froth flotation are provided. The apparatus includes a flotation column having a slurry feed for introducing slurry into the flotation column, a bubble generator for generating bubbles of gas at the bottom of the flotation column and a froth overflow at the top of the flotation column for collecting and discharging a froth fraction of the slurry. The central portion of the flotation column includes a plurality of vertically-spaced tail ports disposed alternately on opposite sides of the flotation column for discharging a non-float fraction of the slurry. In addition, a single, fluid-impermeable baffle having at least two edges is associated with each tail port. The baffles are of sufficient size to block the vertical flow in at least 50% of the horizontal cross-sectional area of the flotation column to thereby create a quiescent flow zone in the area of each tail port, wherefrom the non-florable fraction of the slurry is removed.

Abstract: The invention relates to a method and an apparatus for the separation of hydrophobic substances by froth flotation that basically consists of feeding pulp in the form of a thin layer on at least a lower gas-permeable slanted surfaces in which low pressure gas is injected generating small bubbles that collect hydrophobic particles. The froth containing concentrate is separated and washed before removal in a froth reservoir formed by a lower gas-permeable slanted surface and a wall at its lower end. At the top of the wall, the froth overflows to a launder for removal. At the bottom of the wall, the pulp containing the tailings discharges through an opening. Froth washing is performed by means of baffles that force the froth to flow underneath water sprays.

Abstract: A process and apparatus for pneumatic flotation include thinning a conditioned and gassified pulp and then forming them in the separation chamber into an enclosed free jet.

Abstract: Method and apparatus for the separation of particles from a particulate suspension. The apparatus comprises a rotating flotation drum (10) with a feed distribution chamber (13). Particulate suspension feed enters the chamber through a delivery pipe (20). The feed passes through holes (21) into the particle collection chamber (22). Air is passed into the particulate suspension through a porous inner wall (29) and a froth is generated. The froth and particulate suspension pass into a froth cleaning chamber (32). The froth is washed by being sprayed from a washwater distribution pipe (47). Froth is removed from the drum by a froth scraper (49) through a froth removal chute (50). Unfrothed particulate suspension passes through openings (40) into a weir chamber (41) and is removed through a launder (45).

Abstract: An apparatus for separating impurities from coal, includes a device for removing a predetermined amount of ash-forming substances from the coal and a device for removing a predetermined amount of high specific gravity (e.g., pyrite) from the coal having been processed by the ash-forming substance removing device. The ash-forming substance removing device and the high specific gravity material removing device each possess characteristics that allow them to more efficiently reject different types of mineral impurities from coal.

Abstract: A flotation apparatus has an array of flotation cells which are in serial fluid flow communication from a first to a last cell. Each cell is in overflow communication with an overflow froth receiving receptacle which preferably has a top lip of slightly varying height in each cell. Air inlet and mechanical agitation are provided for each cell and are so positioned to promote an upright circular fluid flow in each cell toward the froth receiving receptacle. Each cell has internal surfaces shaped and oriented to promote the upright circular fluid flow and to discourage the creation of reverse eddy currents within the cell.

Abstract: Apparatus and method for the separation of components of a slurry by froth flotation are provided. The apparatus includes a flotation column having a slurry feed for introducing slurry into the flotation column, a bubble generator for generating bubbles of gas at the bottom of the flotation column and a froth overflow at the top of the flotation column for collecting and discharging a froth fraction of the slurry. The central portion of the flotation column includes a plurality of vertically-spaced tail ports disposed alternately on opposite sides of the flotation column for discharging a non-float fraction of the slurry. In addition, a single, fluid-impermeable baffle having at least two edges is associated with each tail port. The baffles are of sufficient size to block the vertical flow in at least 50% of the horizontal cross-sectional area of the flotation column to thereby create a quiescent flow zone in the area of each tail port, wherefrom the non-flotable fraction of the slurry is removed.

Abstract: A flotation cell with at least one injector for introducing a fluid and aspirating air therethrough has a multi-hole aperture plate. Premixing tube sections are disposed in the injector downstream from the aperture plate at a distance from the plate of at least 0.1 times the diameter of a hole in the aperture plate. The tube sections are oriented perpendicular to the aperture plate and open into a mixing tube.

Abstract: Liquid process streams--such as white water, pressate, or washer filtrate from a pulp and paper mill--are clarified in an efficient manner using a gas sparged hydrocyclone, which takes up a minimum of floor space. A liquid stream having a consistency of less than about 0.5% solids is introduced into a first end of a vortex. Gas is sparged into the liquid in the vortex to cause particles to attach to gas bubbles and move through a rejects outlet at the first end of the vortex, while clarified liquid is removed from a second end of the vortex. A pedestal is typically provided at the accepts outlet, having a radial clearance with the inside of a porous tube through which the gas is sparged that is about 8-12% the radius of the porous tube.

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: The present invention concerns a reactor for removing impurities from a liquid, in particular for de-inking, including a tank (1) within which the liquid to be purified together with a gas or air is introduced (2-3); a drain of the purified accepted through an outlet (7) of said tank (1); inlets (8-11, 9-12, 10-13) at different heights of the tank (1) connected to said purified liquid outlet (7) together with the inlet of gas or air; a rotating shaft (18) inside the tank (1) carrying blades (20, 21, 22, 23) at the different heights of the tank within which the liquid together with gas or air is introduced.; the blades (20, 21, 22, 23) have progressively increasing heights when moving towards the lower portion of the tank (1). The invention also concerns the method embodied by the above-described reactor.

Abstract: A flotation device includes an injector having a flow channel with a variable cross sectional area with respect to the direction of fluid flow through the injector. The injector introduces a mixture of gas and liquid into the device. The injector flow channel has repeated narrowings and widenings in the direction of fluid flow through the injector.

Abstract: A column flotation system including tailings recirculation. The system includes a column for particle separation and a gas injected reactor providing the site for bubble generation within a treated slurry feed. The reactor may contain a plurality of the spaced internal discs that cause shearing of the slurry to generate and entrain bubbles therein. The column may contain internal partitions in order to accommodate additional reactors. Recirculation of the tailings permits increased bubble control and improved particle separation.

Abstract: An apparatus is disclosed for the microbubble flotation separation of very fine and coarse particles, especially coal, and minerals so as to produce high purity and high recovery efficiency. This is accomplished through the use of a flotation column, microbubbles, recycling of the flotation pulp, and countercurrent wash water to gently wash the froth. Also disclosed are unique processes and apparatus for generating microbubbles for flotation in a highly efficient and inexpensive manner using either a porous tube or in-line static generators.

Abstract: A method of separating desired material from undesired material is provided. The method is performed by forming a slurry of material and introducing it into a specially designed flotation reactor chamber. A foam is generated and introduced into the reactor chamber and dispersed into the slurry. A stream of water is provided to separate the undesired portion of the material from the desired portion of the material that has adhered to the bubbles in the foam.

Abstract: An apparatus for separating by froth flotation hydrophobic and hydrophilic particles contained in an aqueous slurry, the apparatus comprising a generally vertical tubular column having an upper froth zone, an upper separation zone, a lower separation zone, an air inlet zone, and an intermediate feed inlet zone; a feed inlet, air inlet, froth outlet and a tailings outlet; an upper baffle unit comprising a plurality of horizontally extending upper baffle plates, a vertical upper support member including an upper end portion, and first upper apparatus for removably mounting the upper baffle plates on the upper support member at predetermined vertically spaced positions; each of the upper baffle plates comprising a mounting aperture and a plurality of flow apertures; and a second upper apparatus for removably supporting the upper support member in the column with the upper baffle plates in the upper separation zone. The apparatus can include a lower baffle unit.

Abstract: A method for the beneficiation of mineral ores by the flotation method whereby a slurry is introduced under pressure into the top of a first column through a downwardly facing nozzle, and air is entrained into the slurry forming a downwardly moving foam bed in the first column. The foam bed passes from the bottom of the first column into a second column where the froth and liquid separate, the froth carrying the values floating upwardly and over a weir and the liquid being drained with the gangue. The liquid/froth interface level in the second column is kept above the bottom of the first column, and the air flow rate into the top of the first column is controlled to keep the first column substantially full of foam.

Abstract: A flotation cyclone for flotation of small particles of less than 30 .mu.m, comprising a cylinder (1) with an upper section, having a porous wall (4) and an extension (6) having a solid wall, said upper section being provided with a tangential inlet (2) and being covered with a lid, having a vortexfinder (10) as a foam outlet, and being surrounded by a gas chamber (3) having a gas inlet (3'), surrounding said porous wall (4), and being provided at the lower end of said porous wall (4) with a weir (5), while the extension (6) of said cylinder, having a solid wall, is provided at its lower end with a liquid as a blocking device.

Abstract: An apparatus and method for de-inking waste paper pulp using a foam flotation process to recycle printed waste paper for the manufacture of new paper. Pulped printed paper is fed as a slurry to an inlet of a shallow tank. Internal guide walls in the tank establish a flow path from the inlet to an outlet. The walls are sized and positioned to create a generally uniform cross-sectional flow area. A plurality of modules are disposed along the flow path. Each module includes at least one injector that aerates the flow and an extractor that removes floated ink foam. A portion of the flow from each module is recycled to an upstream module, preferably by a conduit and associated pump. In a preferred form, an injector (or injectors) alone located at the inlet is fed by the next downstream module and an extractor alone is located near the outlet. The invention also includes a main recycling loop from the downstream end of the flow path to the upstream end.

Abstract: A high efficiency method for the recovery of relatively coarse constituent utilizing a flotation column is provided. The method broadly includes the steps of (1) establishing and maintaining a net upward flow of water (negative bias) through the upper portion of the flotation column which is maintained below a predetermined critical limit; (2) establishing and maintaining an upwardly moving stream of diffuse air which is introduced at the lower portion of the flotation column and which has a superficial air velocity between about 0.5 and 2.0 cm/sec.; (3) introducing a feed stream comprising a slurry of the ore into the upper portion of the flotation column wherein the mineral particles therein substantially range between about 20 mesh (840 microns) and about 325 mesh (44 microns) in size; (4) establishing and maintaining the percent solids in the flotation column between about 35 and 50%; (5) establishing and maintaining column throughput of the slurry between 1.8 and 4.0 tons/hour/sq. ft.

Abstract: The invention relates to a flotation column including a plurality of controlled recycle chambers intentionally introduced into the column to cause the non-float fraction or gangue to drop down in the main float stream while the desired float fraction travels in the opposite direction by recycling to continually mix the pulp while coursing through the column. Recycle zones are positioned on the periphery of the main passage or flotation zone within chambers located in series along the column. A portion of the slurry is drawn into a recycle zone where it passes downwardly to return to the flotation zone or the main passage through the column to again be swept through the column.

Abstract: A flotation method for separating particulate material including at least two separate passageways within each of which slurry is separated from froth by an interface, a feed supply within each passageway for feeding the slurry into each passageway below the interface, bubble generator located below or within the passageways, and at least one tailings outlet below the bubble generator.

Abstract: The flotation apparatus removes ink- and contaminant particles from a fiber stock suspension which is produced during the preparation of waste paper. Admixing of air to the fiber stock suspension is accomplished in stepped diffusors. The fiber stock suspension admixed with air, prior to infeed into a flotation container, is guided through a deflection element effective as an impact mixer and followed by a mixing diffusor having a preferred flow direction. This flotation apparatus is especially suited for eliminating disturbing or spurious substances which are present throughout a relatively wide grain size spectrum. A particularly preferred construction uses one or more closed flotation containers, wherein the air effluxing from the flotation foam can be advantageously re-used for aeration of further infed fiber stock suspension.

Abstract: A floating method employing a cylindrical chamber having a tapered bottom to which there are secured a pipe for feeding a flotation pulp carrying mineral particles of fine fraction and a pipe for discharging gangue. Secured to the walls of the chamber is a trough for collecting froth concentrate, and a group of pulp aerators, whereas positioned axially inside the chamber is a group of tapered shells spaced equidistantly from one another with bases of larger diameter thereof facing the top part of the chamber and resting substantially at one tapered surface. Positioned over the chamber is a means for feeding mineral particles of coarse fraction in the form of a hydrocyclone, a cylindrical casing of this hydrocyclone having a pipe for evacuating the liquid phase of the floatation pulp positioned tangentially and communicating with the pipe for feeding the flotation pulp carrying mineral particles of fine fraction.

Abstract: This invention pertains to a multi-st vessel through which the to-be-cleaned fluid flows. Aeration assemblies within the inner cells disperse micro-fine gas bubbles into the fluid for cleaning purposes. Additionally, the inlet piping contains a separator that begins the separation process before this fluid is discharged into the first cell. An L-shaped passageway interconnects the various flotation cells of this separator with the entrance of each such passageway being at an elevation below its exit. A weir is located within each flotation cell that is adjustable as needed. This weir empties into a channel alongside the seprator vessel that collects the separated contaminants flowing over the weir for later disposal.

Abstract: A method and several embodiments of apparatus are disclosed for use in foam flotation separation. The method discloses performing the separation in a module operated at nonatmospheric pressure, and the apparatus disclosed are suitable for use as the module of the method. Both the method and the apparatus contemplate positive and negative pressure operation.

Abstract: The froth flotation apparatus includes a gas bubble-particle contact unit including a mixing structure for breaking a gas into fine bubbles,such as a packed tower packing or mechanical agitator, and a separate phase separation unit. A conditioned aqueous pulp containing a mixture of hydrophobic and hydrophilic particles and a substantially inert gas, such as air, are introduced into and combined in one end of the contact unit and subsequently flow concurrently through the mixing structure, such that the gas is broken into fine bubbles which intimately contact and become attached to the hydrophobic particles. The resulting gas bubble-particle mixture is introduced into the phase separation unit which is operated under substantially quiescent conditions. A concentrate fraction containing primarily hydrophobic particles and a tailing containing primarily hydrophilic particles are discharged from the upper and lower portions of the phase separation unit, respectively.

Abstract: An apparatus and method for de-inking waste paper pulp using a foam flotation process to recycle printed waste paper for the manufacture of new paper. Pulped printed paper is fed as a slurry to an inlet of a shallow tank. Internal guide walls in the tank establish a flow path from the inlet to an outlet. The walls are sized and positioned to create a generally uniform cross-sectional flow area. A plurality of modules are disposed along the flow path. Each module includes at least one injector that aerates the flow and an extractor that removes floated ink foam. A portion of the flow from each module is recycled to an upstream module, preferably by a conduit and associated pump. In a preferred form, an injector (or injectors) alone located at the inlet is fed by the next downstream module and an extractor alone is located near the outlet. The invention also includes a main recycling loop from the downstream end of the flow path to the upstream end.

Abstract: The invention relates to a flotation-deinking-device comprising a flotation vessel and at least one inlet for introducing the suspension into the flotation vessel, the inlet being a staged diffusor (12) in which in a region of the stage transition (26) an air inlet opening (20) is arranged. A turbulence generator (28) without an air supply is arranged upstream of the stage transition (26) as seen in the direction of flow.