Abstract: The present invention relates generally to a process for flotation of sulphide minerals where a flotation pulp is separated into a coarse stream and a fine stream, preferably containing particles coarser than about 30 micron and particles finer than about 30 micron, respectively. Typically, alkali and depressant are added to the coarse flotation stream only and acid and activator are added to the fine flotation stream only. During flotation of the fine stream, acid and/or activator may be added at the conditioning, cleaning, re-cleaning, cleaner-scavenging or third cleaning stage. During flotation of the coarse stream, alkali and/or depressant may be added at the conditioning or cleaning stage.

Abstract: The present invention relates to a froth flotation mechanism located in a flotation cell, comprising a directional element suspended from the lower end of a hollow shaft extending to the lower section of the cell and vertical vanes attached to said directional element, which extend above and below the directional element and horizontally beyond the directional element. The substantially horizontal circular plate of the directional element is symmetrically attached around the shaft at its centre and the outer edge of the central plate is bent downwards to form the lap of the guiding part. The gas spreading plate is located on the inner side of the lap. The flotation cell is comprised of a cylindrical lower section, a middle section located above it in the form of a truncated cone widening upwards, and a cylindrical upper section attached to the top of it.

Abstract: A separation apparatus and method for use in separating magnetic material from non-magnetic material that includes the use of a magnetic grid, e.g., a permanently magnetic grid, which defines a plurality of openings. The grid assists in preventing magnetic material from being transported to an overflow.

Abstract: A fluid level control apparatus for selectively controlling the movement of liquid flowing out of a flotation cell is described. The fluid level control apparatus is significantly reduced in size in comparison with the flotation cell or cells to which it is connected which enables less expensive construction and reduced operating costs in terms of both the equipment and the plant as a whole. The fluid level control apparatus comprises a vessel having a valve positioned therein which includes a valve body structured with a curved surface which provides selective and finite control of fluid flowing through the vessel of the control apparatus. In one embodiment at least one of the inlet and outlet of the control apparatus exhibit a cross-sectional area taken transverse to the intended fluid flow therethrough having a substantially horizontal dimension which is greater than a substantially vertical dimension.

Abstract: The invention relates to a flotation machine which at least contains a flotation cell having a means for feeding slurry in the flotation cell, a means for feeding air into the slurry and producing froth, a means for removing froth from the flotation cell and a means for removing tailings from the flotation cell. According to the invention the flotation cell (1,21) is provided with at least one rotating froth removal device (8,26) immersed at least partly in the froth (9,27) and so shaped that one end of the froth removal device (8,26) is extendible over the launder (12) attached to the flotation cell (1) in order to recover the froth (9,27) from the flotation cell (1,21) using the centrifugal force generated by the froth removal device (8,26).

Abstract: A process of separating a desired constituent from a mixture of particulate matter including the steps of: conditioning a liquid mixture of particulate matter with a frothing agent to create a pulp; aerating the pulp to generate a float fraction of froth supported on the surface of a non-float fraction of pulp; separating a portion of froth from the float fraction; draining the separated froth; washing the separated froth with a liquid to dislodge particles comprising one or more of non-selectively attached, entrained, and entrapped particles; and recovering the washed froth, is disclosed herein. Also disclosed herein are a froth cleaning apparatus and a froth flotation apparatus for separating a desired constituent from a mixture of particulate matter.

Abstract: An apparatus for separation of solids in froth is presented. The apparatus includes: a housing (1), establishing a chamber (2) for flows of liquid and solid material and a froth bed (30) on the liquid; feeding means (14) for getting incoming material to be separated in contact with said froth bed (30); discharging means (6) for solid material near the bottom (12) of said housing (1); aerator means (24, 26) under the liquid surface (78) for creating bubbles and thus forming said bed of froth (30) and generating movement on the bed of froth (30); means for discharging froth from the housing (1) including at least a froth outlet (74). The apparatus is characterized by a surface (32) connected to said feeding means (14) so as to reduce the vertical speed component of the material being fed with the feeding means (14) from above said froth bed in and on to said froth bed (30).

Abstract: The invention uses machine-vision to improve the performance of a flotation operation to provide a substitute for conventional human vision and problem-solving abilities. The invention redirects the conventional approach of “characterizing the froth” to “measuring the froth characteristic.” The invention provides a method of monitoring and controlling a mineral mixture flow in a froth flotation cell of a flotation plant which includes the steps of obtaining a series of digital images extracted of froth characteristics from a flotation cell. The digital images are transmitted to a computer for processing thereof into parameter signals of digital parameter froth characteristics.

Abstract: Invention relates to a flotation machine which at least contains a flotation cell (2) having a means for feeding slurry in the floatation cell, a means for feeding gas into the slurry and producing aerated slurry (4) and froth (3), a means for removing froth from the flotation cell and a means for removing tailings from the flotation cell, when the flotation cell (2) is provided with at least one separation device (5), which is arranged to float at the interface (6) between phases having different densities, such as froth (3) and aerated slurry (4), in order to improve the removal of froth phase from the flotation cell.

Abstract: An improved flotation separation apparatus for separating and classifying diverse, liquid-suspended solids having a plurality of high volume air bubble infusers. Each infuser includes a circular cavity defined by an interior circumferential wall. A plurality of stationary impinging plates projecting from the interior circumferential wall into the circular cavity and equally spaced circumferentially in series therealong. An injecting stream of water and air impinges upon the impinging plates in series to repeatedly create, divide and subdivide air bubbles as the injection stream transverses the series of impinging plates.

Abstract: The invention relates to a flotation machine which at least contains a flotation cell having a means for feeding slurry in the flotation cell, a means for feeding air into the slurry and producing froth, a means for removing froth from the flotation cell and a means for removing tailings from the flotation cell. According to the invention the flotation cell (1,21) is provided with at least one rotating froth removal device (8,26) immersed at least partly in the froth (9,27) and so shaped that one end of the froth removal device (8,26) is extendible over the launder (12) attached to the flotation cell (1) in order to recover the froth (9,27) from the flotation cell (1,21) using the centrifugal force generated by the froth removal device (8,26).

Abstract: At the separation of different minerals from the ores by means of flotation, it belongs to known art to monitor a larger part of the uppermost froth layer in the flotation cell by means of a video camera whose signals are analyzed in a digital computer, in order to detect the structure and color of the froth. The new method and apparatus direct and limit the monitoring and analysis to the surface of the floated material within a fixed, narrow strip which is parallel to the overflow edge of the cell and within which the material surface passing it is homogeneous in the stationary state. The said strip thus presents a renewing sample of the surface at the location in question, which sample represents the stationary state in the average sense. The strip is subjected to homogeneous illumination, which may meet the strip at different angles depending on the primary object, i.e. whether the color or structure is being determined.

Abstract: The invention relates to a device for separating solids from liquids by means of flotation, particularly for separating impurities and ink particles from fibre suspensions, with several injectors 10, which are provided inside a flotation cell 1. It is mainly characterised by the injectors 10 being arranged in one row.

Abstract: An apparatus for recovering a desired fraction of a raw material bearing the desired fraction has a vessel or cell defining a treatment chamber therein, with an inlet into the chamber for introducing a slurry of raw material to be treated into the chamber. An attrition zone is defined in a portion of the chamber proximate the inlet in the flow path of material introduced into the chamber, the particles being caused to impact against each other in the attrition zone to cause attritioning thereof. A floatation zone is defined in a distal portion of the chamber, in flow communication with the attrition zone, in which attritioned particles from the attrition zone can be contacted with gas bubbles to form a froth phase separated from the slurry by a slurry-froth interface such that the desired fraction is either selectively taken up into the froth phase by the gas bubbles or selectively left behind in the slurry. An outlet from the chamber for the froth phase is present.

Abstract: A device and process for aerating dispersions, particularly for flotation of pulp suspensions, in a de-inking process where the pulp suspension containing dirt particles is sprayed into a tank together with air. The air is injected at a minimum of two successive points and mixed with the suspension.

Abstract: The invention relates to a flotation cell line, wherein there are installed, in order to treat the flotatable material, several flotation cells so that the flotatable material can be set to flow through the flotation cell line. According to the invention, the flotation cells (, 1, 2, 3, 4, 5; 31, 32, 33, 34, 35) that are arranged successively in the flowing direction (22, 52) of the flotatable material, are at least partly installed in parallel with respect to each other.

Abstract: The invention relates to a method for improving the operation of a flotation cell line, said flotation cell line comprising several flotation cells (1, 2, 3, 4, 5; 11, 12, 13, 14, 15) that are connected by means of liquid stream flow. According to the invention, at least part of the material flotated in the flotation cell line is conducted past the cell (1, 11) that is located first in the flotation cell line, when seen in the flowing direction (7, 16) of the flotatable material.

Abstract: A fluid level control apparatus for selectively controlling the movement of liquid flowing out of a flotation cell is described. The fluid level control apparatus is significantly reduced in size in comparison with the flotation cell or cells to which it is connected which enables less expensive construction and reduced operating costs in terms of both the equipment and the plant as a whole. The fluid level control apparatus comprises a vessel having a valve positioned therein which includes a valve body structured with a curved surface which provides selective and finite control of fluid flowing through the vessel of the control apparatus.

Abstract: A system for removing bleed-through contaminants from OCC fiber pulp includes a plurality of primary flotation cells, with each primary flotation cell having an inlet, an accept outlet and a reject outlet. The inlet and the accept outlets of the plurality of primary flotation cells are coupled together in a series configuration. The reject outlets are coupled together in parallel. A secondary flotation cell has an inlet, at least one accept outlet and a reject outlet. The secondary flotation cell inlet is fluidly coupled with the reject outlet of the primary flotation cells. A water clarifier has an inlet, a clarified water outlet and a sludge outlet. The inlet is connected with the reject outlet of the secondary flotation cell.

Abstract: Process and device for the flotation of contaminates out of an aqueous fibrous suspension using a foam. The process includes creating the foam, introducing the fibrous suspension into the foam, transferring contaminates from the fibrous suspension to the foam, and removing some portion of the fibrous suspension from the foam as an accepted stock. The device includes a liquid containing area, a mechanism for introducing a gas into the liquid containing area, and a mechanism for introducing the fibrous suspension into a foam containing area arranged to be adjacent the liquid containing area.

Abstract: A flotation machine is provided which includes at least one flotation cell having an inner chamber. The fiber suspension is transported into the inner chamber, and a gas is injected into the fiber suspension within the inner chamber at a temperature below 20° C. to cause the wax to clump within the fiber suspension. The clumped wax is removed from the fiber suspension.

Abstract: A method for optimising a mineral recovery process. A slurry 10 is fed to a conditioning step 20. The condition slurry 30 is then provided to a flotation circuit 40 to recover a concentrate 50. The remainder of the slurry is then rejected as tail 60 or passed for further processing. The present invention provides apparatus for analysing a sample stream 100 of the slurry. A sample stream 100 is provided to an analysis device 200 which treats the sample with an oxidising gas similar to the oxidative treatment 20. Several parameters are measured before and/or after the oxidative treatment of the slurry. The flotability characteristic of the slurry is then determined as a function of the measured parameter(s). The result is used to optimise mineral recovery. This apparatus can be used intermittently or continuously to provide on-going optimisation of the mineral recovery circuit.

Abstract: A device and process for aerating dispersions, particularly for flotation of pulp suspensions, in a de-inking process where the pulp suspension containing dirt particles is sprayed into a tank together with air. The air is injected at a minimum of two successive points and mixed with the suspension.

Abstract: Process and apparatus for removing solids from an aqueous fiber suspension in a flotation container that includes a drainage section. The process includes adding gas bubbles to the fiber suspension entering the flotation container, and collecting a flotation foam formed within the flotation container. The flotation foam includes the solids to be removed. The process also includes laterally moving the flotation foam in the drainage section, such that at least a portion of fluid within the flotation foam is drained from the flotation foam, collecting the drained fluid in the drainage section, discharging the drained fluid from the drainage section, discharging the flotation foam as a rejects material, and discharging a purified fiber suspension as an accepted stock suspension. The apparatus includes a flotation container, and a drainage section coupled to the flotation container. The drainage section is arranged to drain at least a portion of fluid from a flotation foam.

Abstract: This invention relates to a method for the treatment of a desulfurization absorbing fluid after gas-liquid contact with combustion exhaust gas in which fine particles of unburned carbon and other materials are efficiently removed from the desulfurization absorbing fluid to improve the quality of a by-product (e.g., gypsum) obtained therefrom. The method of this invention comprises the steps of feeding a gas into a desulfurization absorbing fluid (A) containing fine particles of unburned carbon and other materials and thereby producing gas bubbles so as to cause the fine particles to adhere to the surfaces of the gas bubbles and create a foam phase (D) consisting of the gas bubbles; and breaking the foam phase (D) to obtain a liquid (E) containing the fine particles.

Abstract: An elutriation apparatus which combines pressurized liquid nozzles (16A) and the low energy air nozzles (20) producing bubbles for flotation and separation of trace materials in a heterogeneous mixture of materials is described. Quantitative separation of trace evidence is achieved by the apparatus by a closed system of mechanical separations using the water and the air to isolate and deposit trace evidence on a fine mesh screen filter (17) submerged in the water (24) in a container (23). The method provides a rapid, quantitative and inexpensive method for detection of the evidence in soil samples.

Abstract: A froth flotation cell comprising a tank and an impeller rotatably disposed in the tank for suspending solids and dispersing air in a pulp phase or slurry in the tank, thereby generating froth from the pulp phase. A plurality of radially oriented launders are placed near the top of the tank and have one end connected to an outer launder adjacent the outer periphery of the tank. A secondary launder, concentric with the outer launder may also be placed near the top of the tank and attached to the second ends of the radial launders. The secondary launder is attached to a dispersing mechanism located around the impeller. The secondary launder is in fluid communication with the radial launders, and the radial launders are likewise in fluid communication with the central launder. This provides a network of launders which collects froth at various locations throughout the flotation cell and causes rapid removal of froth from the flotation cell.

Abstract: A cyclonic-static micro-bubble flotation apparatus which includes a single unit flotation device having a cyclonic separation unit in the bottom portion of the device and a column flotation portion which includes packing in the upper portion of the flotation device.

Abstract: A mixture of air, paper stock made from recycled paper, foaming agents and surfactants are injected into a pressurized container. The container has a stock inlet at an end opposite a stock outlet, and three outlets arranged along the top of the container between the stock inlet and the stock outlet. The first top outlet nearest the stock inlet is separated from the second and third outlets by a baffle, and the second and third outlets are separated from the stock outlet by a baffle. Each outlet has a valve which controls flow from that outlet. By adjusting the outlet valves, foam and waste ink is vented from the first and second outlets from the stock inlet, while stock is vented from the third outlet which is closest to the stock outlet. The stock passing through the third outlet is recycled through the container.

Abstract: An apparatus and process for the separation of coal from pyritic impurities using a modified froth flotation system. The froth flotation column incorporates a helical track about the inner wall of the column in a region intermediate between the top and base of the column. A standard impeller located about the central axis of the column is used to generate a centrifugal force thereby increasing the separation efficiency of coal from the pyritic particles and hydrophillic tailings.

Abstract: The invention realizes a baffle for a reactor for liquids purification, said reactor comprising: a tank containing the liquid to be purified; a plurality of injectors suitable for introducing in the tank said liquid to be purified; one or more rotating blades arranged inside said tank, suitable for keeping agitated said liquid to be purified. Said baffle is applied to at least one of said one or more blades and it is formed of a disk supplied with a plurality of through openings suitable for favoring, during the rotation of said blades, the passing of the descending flow of liquid during the purification, and of the ascending flow of aeriform substance dispersed in said liquid, in order to favor the stabilization of the turbulent motion of the liquid itself in correspondence with said blades.

Abstract: Flotation equipment for mineral processing having a single column with multi-sections or chambers in which the partitions between chambers can be moved for optimum hydrodynamics resulting in the separation of different particles in each chamber which rises to the top of the chambers entrained with air bubbles to form froth layers. Provision is made for processing large particles in at least one of the chambers.

Abstract: An apparatus for producing highly pressurized air-saturated water intended preferably for dispersion in flotation plants, has, preferably, an upstanding cylindrical pressure vessel (21) which, in operation, is filled partially to a controlled level with pressurized water flowing through an opening in the bottom part of the vessel, and partially by continuously delivered pressurized air, wherein the air is dissolved in the water during its passage through the pressure vessel (21). Pressurized water is delivered to the apparatus in the upper end of the pressure vessel (21) through a spray element (24) or the like to effectively break up the water flow. The spray element is arranged so that at least part of the water flow is sprayed on to the inner wall surfaces of the vessel (21) which, in operation, surround the air-filled part and together with this part produce a curtain of water which substantially covers the inner wall surfaces.

Abstract: Equipment 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: A flotation cell row including a row of cells through which, in use, a process liquid flows in turn, including a first bank of cells having a last cell 4 being the most downstream cell and a second bank of cells having a first cell 5 being the most upstream cell, the second bank being the bank immediately downstream of the first bank, in which one or both of the last cell 4 and the first cell 5 are structured to define a port 37 having a rim through which, in use, the process liquid flows from the last cell 4 to the first cell 5, and a valve member 10 mounted for movement between a closed position abutting the rim 44 and an open position spaced from rim 44, to control flow of process liquid through the port 37.

Abstract: The present invention relates to a hydraulic reactor and classifier, with ultrasonic application for a continuous process of separation and recovering minerals or other type of materials or for the production of chemical compounds. It comprises a body of two main sections, an upper part and a lower part. The upper part comprises a container, a loading compartment, a lamella package, at least one ultrasound transducer package and a peripheral weir. The lower part comprises an inverted semi-pyramidal container having a square base, the square base attached to the upper part, at least one ultrasound transducer package at different location within the reactor to distribute the ultrasound effect all over the slurry flowing through the reactor, a nozzle for delivering a liquid or a gas. The final part comprises a pinch valve for discharging coarse particles as a slurry.

Abstract: An apparatus for extracting floatable minerals from a slurry (3). Slurry (3) is fed into a tank (2) via a feed inlet (25) and agitated and aerated so as to create an upper zone containing froth enriched with the floatable minerals. The agitation and aeration are also regulated to create a lower zone (41) containing a relatively dense or coarse component of the slurry (3), and an intermediate zone (42) containing a substantially less dense or finer component of the slurry (3). The surface froth is progressively withdrawn via a launder (30) thereby to produce a flotation concentrate. Similarly, the relatively dense component of the slurry (3) is progressively withdrawn from the lower zone (41) via a bottom inlet (26), and the relatively less dense of the slurry (3) is progressively withdrawn from the intermediate zone (42) via a side outlet (28).

Abstract: Methods for washing sawdust are disclosed which include providing a mixture of sawdust and water to a vessel, subjecting the mixture to a reduced pressure so that gases present in the sawdust cause expansion therein and the sawdust rises to the surface of the mixture while the contaminants descend within the vessel, and withdrawing the sawdust from the vessel, in which the sawdust is withdrawn from the vessel at a location above the point where the sawdust and water enter the vessel. Apparatus for carrying out this method is also disclosed.

Abstract: A flash flotation device (1) comprises a tank (2) to contain slurry (3) incorporating minerals to be extracted, a feed inlet (25) for admission of slurry (3) into the tank (2), agitation means (10) to agitate the slurry (3) within the tank (2), aeration means to aerate the slurry (3) whereby floatable minerals in suspension form a surface froth for removal via froth lip (29), a bottom outlet (26) for withdrawal of relatively coarse or dense components of the slurry (3) from the tank (2), and a side outlet (28) to regulate the level of slurry (3) in the tank (2).

Abstract: Hydrophobic material is selectively separated from an aqueous feed by forming gas bubbles in a flow of the feed, forming hydrophobic material/gas bubbles aggregates by motionless mixing and separating the aggregates as a froth by use of centrifugal action.

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: 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 method of processing recycled paper which contains such a high amount of wax, hot melts or stickies that they would be expected to cause a stoppage of the paper-manufacturing machine. The paper to be recycled is pulped in a pulper and passed on to respective subsequent stages which include a despecker, grader and hydrocyclone. Pulping takes place at a temperature of at least 60.degree. C., and at the same time subjects the paper to a high shear action. The processing line includes a pulp-thickening stage, preferably after the processing stages mentioned, in order to separate off a very high proportion of the wax, hot melts and stickies finely dispersed in the pulper.

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: A froth crowder device is disclosed for incorporation into a froth flotation cell to improve the froth removal dynamics of the flotation cell. The froth crowder device is positioned within a froth flotation cell above and below the overflow launder, and provides a sloped surface to direct froth toward the overflow launder in an expedited manner. Experimental data confirms that use of a froth crowder device as disclosed expedites movement of the froth toward the launder for more efficient operation, permits operating the rotor of the flotation cell at reduced speeds without compromising the efficiency of operation, and reduces the amount of air necessary to produce a froth in the cell. Experimental data also confirms that little or no surface eddies are observed in froth flotation cells in which a crowder device as disclosed is used.

Abstract: The present invention is directed to a type of flotation machine that combines three separate operations in a single unit. The flotation machine is a hydraulic separator that is capable of reducing the pyrite and other mineral matter content of a coal. When the hydraulic separator is used with a flotation system, the pyrite and certain other minerals particles that may have been entrained by hydrodynamic forces associated with conventional flotation machines and/or by the attachment forces associated with the formation of microagglomerates are washed and separated from the coal.

Abstract: The automatic regulator device comprises a channel for measuring the level and density of pulp in the chamber of a floatation machine, in which two bubbling pipes are in communication with a differential pressure pickup connected to the input of a frother flow-rate regulating channel and to one input of a correction unit whose other input is connected to a pressure pickup communicating with one of the bubbling pipes. The output of the correction unit is connected to the input of a circuit designed to regulate the rate of flow of water with frother in a pulp level stabilizing channel, the output of said circuit being connected to an actuator valve installed on a pipeline feeding water with frother and furnishing a control signal with respect to a pulp level deviation from a preset value.

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.