Abstract: Provided is a method for preparing a fluid containing size-controlled particles that is optimized with respect to use of a target fluid as a matrix fluid under conditions approximating actual conditions. In a preferred embodiment, size-controlled SiO2 particles are obtained by mixing and dispersing SiO2 starting particles having various sizes in a N2 carrier gas followed by fractionation with a fractionator. The size-controlled particles are electrostatically collected by a porous member from the carrier gas flow. Ultrasonic vibrations are then applied to the porous member while a HCl matrix fluid flows through the porous member loaded with the size-controlled particles. This causes release of the size-controlled particles from the porous member and their admixture and dispersion into the HCl matrix fluid.

Abstract: A process for continuously discriminating between a contaminated plastic material containing trapped volatile contaminants and plastic material which contains an acceptable threshold of contaminants comprising first supplying a continuous source of plastic material wherein the plastic material contains trapped volatile contaminants and feeding a sample of the plastic material preferably to the input section of an auger conveyor. The auger conveyor contains a barrel and a transfer screw positioned within the barrel with flights thereon for conveying the plastic material, the auger also connected to an output section which itself is connected to a detector for detecting trapped volatile contaminants.

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: A method for reducing both reagent consumption and scale formation in a mineral separation circuit employing sulfoxy compounds as reagents. The method involves introducing into the mineral separation circuit a non-oxidizing gas in a quantity sufficient to reduce the degree of oxidation of the sulfoxy radical. Preferably the gas is introduced during the reagent conditioning and flotation stages, the stages where the presence of dissolved oxygen in a slurry is most likely to create the conditions conducive to oxidation of the sulfoxy radicals which result in reagent consumption and scale formation problems. The process is suitable for a wide range of mineral separation circuits which use sulfoxy reagents for the separation of sulfidic minerals including chalcopyrite, pentlandite, pyrite, sphalerite, pyrrhotite or galena.

Abstract: A process for the separation of minerals of different mineralogical character. The process involves conditioning a milled slurry or a slurry of a flotation concentrate which contains a mixture of valuable sulfidic minerals and non-sulfidic gangue material with an inert/non-oxidizing gas and/or a reducing/deoxifying agent. The conditioning is conducted to achieve a controlled dissolved oxygen content or electrochemical reduction potential conducive to the separation of the valuable sulfidic mineral, non-sulfidic gangue material. The inert/non-oxidizing gas and/or reducing/deoxifying agent may be added to the slurry in a quantity sufficient to increase rejection of the non-sulfidic gangue minerals or to improve the selectivity between the valuable sulfidic minerals and non-sulfidic gangue minerals.

Abstract: A method of increasing both flotation selectivity and effectiveness of a sulfoxy radical-containing reagent added to a mineral separation circuit. The method involves adding a non-oxidizing gas to the mineral separation circuit prior to and/or simultaneously with the addition of the sulfoxy radical-containing reagent in a quantity sufficient to achieve a chemical environment conducive to flotation separation of minerals. The process is suitable for use with a broad range of slurries and flotation concentrates having a mixture of valuable materials including sulfidic copper minerals, sulfidic and non-sulfidic copper minerals, valuable lead and/or zinc and/or nickel minerals, sulfidic iron minerals (particularly pyrite) and non-sulfidic gangue material. It is particularly suitable for polymetallic ores containing economic values of copper and/or lead and/or zinc and/or nickel which is frequently in association with iron sulfide.

Abstract: A disposable first tube (68) extends axially through, and is detachably connected to, an annular main body (10'). An input piezo electric element (38) is attached to a first end of the tubular main body (10'). A second, sensor piezo electric element (40) is attached to the opposite end of the main body (10'). A nozzle (20') having a nozzle passageway (110) and a discharge opening (112) is detachably secured to an outlet end of the first tube (68). A second tube (102) within the first tube (68) delivers a core liquid to the nozzle passageway (110). A sheath liquid is delivered through a space in the first tube (68) surrounding the second tube (102). The nozzle passageway (110) forms the core and sheath liquids into a small diameter jet stream. Electrical energy is delivered to the input piezo electric element (38), to vibrate the nozzle (20') and break the jet stream into droplets.

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: 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: A descalant means, comprising L.sub.E structured liquid crystals which when placed close to, or into a liquid stream, cause the formation of microscopic liquid crystalline structures, which act as nucleation sites for the formation of crystal structures of normally liquid-soluble or insoluble salts, and other suspended particles, these crystalline structures being chemically stable and causing a large reduction in the scaling potential of the liquid, thereby avoiding scale buildup on metal or other containment surfaces and also initiating descaling of surfaces already containing scale buildup. Furthermore, said means will reduce the amount of detergents, soaps, surfactants and polymers required in washing and other forms of water use.

Abstract: A disposable first tube (68) extends axially through, and is detachably connected to, an annular main body (10'). An input piezo electric element (38) is attached to a first end of the tubular main body (10'). A second, sensor piezo electric element (40) is attached to the opposite end of the main body (10'). A nozzle (20') having a nozzle passageway (110) and a discharge opening (112) is detachably secured to an outlet end of the first tube (68). A second tube (102) within the first tube (68) delivers a core liquid to the nozzle passageway (110). A sheath liquid is delivered through a space in the first tube (68) surrounding the second tube (102). The nozzle passageway (110) forms the core and sheath liquids into a small diameter jet stream. Electrical energy is delivered to the input piezo electric element (38), to vibrate the nozzle (20') and break the jet stream into droplets.

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 multi-stage froth flotation process is provided for concentrating sulphide minerals or middlings containing non-ferrous metal values such as nickel, cobalt and copper, which co-exist with significant amounts of pyrrhotite. The process is carried out without relying on any specific reagent as pyrrhotite depressant, but rather by exploiting the natural pulp environment with low REDOX potentials generated by mild steel grinding media in the grinding step preceding the froth flotation. The concentrate from the flotation stage(s) in which the REDOX potential rises above a predetermined value, is recycled back to the grinding step and/or to preceding flotation stage(s) from which concentrate is collected as the final product or is subjected to an up-grading in a further cleaning stage.

Abstract: A method for recovering materials, in particular rejects or scraps of sheathed cables or wires, comprises introducing the parts into an enclosed space and placing them on a support provided with a drain, removing the oxygen from the enclosed space, raising the temperature inside the enclosed spaced until it reaches a melting temperature of one of the materials so that it drains through the drain, collecting the melted material in a recovery tank maintained at a temperature less than or equal to the melting temperature, then raising the temperature inside the enclosed space to cause the material remaining on the parts to dissipate in the form of vapour or gas, and recovering after cooling, the material drained into the recovery tank and the material or materials remaining on the support.

Abstract: A ferrofluid sink/float separator for separating nonmagnetic materials of different densities comprises a horizontal separating tank and a magnetic field generating mechanism. The separating tank is filled with a ferrofluid capable of being induced by the magnetic field generating mechanism to have a magnetic field gradient and various apparent densities in the direction of earth gravity. The magnetic field generating mechanism comprises two magnetic poles spaced at an interval and a gap which is defined by the two magnetic poles and is located under the horizontal separating tank.

Abstract: The present invention concerns a method of separating variable ores containing copper, lead, zinc and the like as the refining material for non-ferrous metals and gangue minerals such as pyrite, quartz, feld spar and the like from dug out ores and, particularly, it relates to a flotation method. For obtaining non-ferrous metal valuable ores as concentrates from ores by a flotation method, flotation is conducted by using gaseous sulfurous acid or aqueous sulfurous acid as a depressant for controlling the floatability of pyrite. The flotation method comprises measuring the redox potential of an ore solution before and after the addition of gaseous sulfurous acid or aqueous sulfurous acid and determining an optimum addition amount by utilizing a proportional relationship present between the difference of the potential and the valuable quality enhancing rate.

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: A three-dimensional warehouse in which its working efficiency is improved with respect to the receiving and taking out of articles and its housing efficiency is improved. The warehouse has entrance/delivery stations provided at a plurality of stories, for housing blocks provided on a vertical plane. The warehouse also has horizontal conveyors disposed to circulate along the periphery of a housing area by connecting the horizontal conveyor of the same story. The warehouse may further include a vertical conveyor for connecting the horizontal conveyors in the vertical direction. The articles can be taken in and out efficiently by driving and selecting the conveyor and the entrance/delivery stations to be used.

Abstract: In a method for the automated processing of bulk mail, envelopes are transferred to a receiving apparatus in bulk fashion (from incoming mail trays or the like) for the extraction of documents contained by the envelopes, and the extracted documents are delivered to a remittance processing device, preferably both automatically and without the need for human intervention. Subsequent processing of the extracted documents within the remittance processing device then proceeds in usual fashion, completing the acquisition of information which is necessary to ready such documents for deposit into the banking system. Also disclosed are various presorting functions so that only envelopes containing documents of a specified type will be fully processed, other sorting functions such as the identification of specific types of documents (invoices or checks) for separate processing, and the use of a single extraction device to deliver extracted documents to either one, or a series of remittance processing devices.

Abstract: The invention proposes using liquefied carbon dioxide as a separation agent for flotation and/or sedimentation separation, which is particularly suitable for separating foodstuff mixtures such as meat components, because it can be maintained in liquid phase at the freezing point of water and is inert with respect to many substances of the mixture. By controlling the pressure and/or the temperature at values of about 26 bar and -14.degree. C., the density of the separation agent can be adjusted to correspond to that of water so that water containing substances of the mixture can be readily separated.

Abstract: The present invention is a filtration method and device for separating particles of a suspension according to their mass. The invention includes a rotating uncloggable filter. The filter rotates inside of a stationery housing. Separation by particle size is achieved by adjusting the rotational speed of the filter. The filter is particularly useful for washing photographic suspensions.

Abstract: A method is disclosed for determining the distribution according to size of particles which make up a noncontinuous phase dispersed within a matrix which is not completely soluble in an aqueous solution. The method involves dissolving the matrix containing the particles in an essentially nonaqueous liquid causing the particles to be suspended. The suspension is then eluted through a separating medium which sorts the particles according to size. A detector monitors the effluent from the separating medium and creates a record of the data. This record is then compared to data obtained from known standards in order to estimate the size distribution in the sample.

Abstract: The automatic control device comprises a channel used to measure the level and density of pulp in a chamber of a floatation machine, in which two bubbling tubes communicate with a differential pressure transducer connected to the input of a frother flow control channel and to the input of a correction unit whose other input is connected to a pressure transducer communicating with one of the bubbling tubes. The bubbling tubes are installed in hydrostatic tubes located outside the chamber and communicating therewith at different levels relative to the pulp level. The output of the correction unit is connected to the input of a circuit designed to control the flow rate of water and frother in a pulp level stabilizing channel and having its output connected to an actuator valve of a pipeline feeding water and frother.

Abstract: The invention is directed to a method of regulating a flotation system having an inflow quantity of suspension flow dependent on production demands, including a primary flotation stage and a secondary flotation stage where the secondary flotation stage treats the froth of the primary stage, transporting de-aereated froth from the primary flotation stage to a collection vessel which is in fluid communication the secondary flotation stage; recycling suspension flow from the secondary flotation cells of the secondary flotation stage in part to an inlet of the primary flotation stage, and in part to an inlet of the secondary flotation stage, and regulating the level of de-aereated froth in the collection vessel by controlling the amount of suspension flow recycled from said secondary flotation stage to the inlet of the secondary flotation stage.

Abstract: A cement mixing and pumping simulator comprises actual and virtual equipment. In response to an operator controlling this equipment, signals representing operating characteristics of a cement mixing system realistically represented by the actual and virtual equipment are generated. These signals are communicated for displaying the operating characteristics to the operator so that the operator obtains real-time responses to the operator's control of the actual and virtual equipment.

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 present invention is further directed towards a method for determining the efficiency of separation of a dense media separation process. This method includes determining an apparent distance a particle must travel in a dense media cyclone to be correctly beneficiated. From this apparent distance, an apparent velocity a particle must achieve to be correctly beneficiated is calculated. This apparent velocity is used, along with cyclone geometry and operational parameters to calculate a divergence value which indicates the efficiency of separation. The present invention also includes a method for selecting cyclone geometry and operating parameters which includes determining separation efficiency and adjusting geometry and parameters in a manner to obtain improved efficiency.

Abstract: The separation density of a dense media comprising a slurry of magnetite and water in a cyclone for beneficiating coal containing refuse is maintained within predetermined limits by: (a) measuring the total solids in an overflow of the cyclone; (b) comparing the total solids with a predetermined correlation with separation density; and (c) changing the relative proportions of the feed flow of magnetite and water to the cyclone when the separation density as determined by the correlation is outside the predetermined limits.

Abstract: A method is disclosed for determining the distribution according to size of particles which make up a noncontinuous phase dispersed within a matrix which is not completely soluble in an aqueous solution. The method involves dissolving the matrix containing the particles in an essentially nonaqueous liquid causing the particles to be suspended. The suspension is then eluted through a separating medium which sorts the particles according to size. A detector monitors the effluent from the separating medium and creates a record of the data. This record is then compared to data obtained from known standards in order to estimate the size distribution in the sample.

Abstract: A process for the flocculation, precipitation, agglomeration or coagulation of substances or microorganisms present in a liquid in a dissolved, colloidally dissolved, suspended or emulsified state and a device for carrying out the process. The respective liquid is exposed to one or several fields of stationary ultrasonic waves, the ultrasonic frequency f being higher than one seventh of a cutoff frequency fo which depends on the kinematic viscosity of the liquid and the effective radius of the particles present in the liquid.The device includes an ultrasonic treatment tank which receives the liquid to be purified and is provided with an ultrasonic transducer radiating the ultrasonic waves to an opposing reflecting surface.

Abstract: This invention provides an apparatus and method for the complete fractionation of submicron particles according to size by capillary hydrodynamic fractionation. This objective is achieved by using small diameter capillaries; introducing a minor fraction of a liquid dispersion of particles to be separated into at least one capillary fraction; passing the minor fraction through the capillary; and, at the exit of the capillary, diluting the minor fraction with the same liquid as is carrying the fractionated sample. These modifications in the flow patterns are essential to the use of capillaries with diameters smaller than 60 microns. This invention is especially adapted for rapid analytical separation of not only rigid colloidal particles but also of soft latexes.

Abstract: In a flotation system, the generated quantity of foam is determined and, independent thereof, process parameters which directly or indirectly affect the generated foam quantity are reduced in their quantity depending on foam quantity. This is brought about by reduction of specific substance flows and also such substance flows that circulate in a flotation system. Production waters used for dilution are partly replaced by fresh water. This precludes an excessive amount of generated foam from causing difficulties in the operation of a flotation system.

Abstract: An improved material separation system and method utilizing control particles of generally known physical characteristics as tracer particles through the separation process. The control particles are generally the same or similar to the materials being separated and are coated with or bonded to a fluorescing dye. The control particles are mixed with the material to be separated prior to separation. The mixture is imposed with a energy source which excites the fluorescent dye causing fluorescing emission. The fluorescing emission is detected at the output of the separation of the mixture to determine if the separation is operating efficiently and as desired.

Abstract: A control system having optoelectric detectors responsive to different solids concentrations and character of the solids of a slurry, the signal of the detectors being input to a process controller which adjusts the rate of addition of chemicals to the feed stream of a froth cell to control the separation of solids from impurities. The impurities pass out of the cell as tailings. The controller calculates a feedforward output from the signals from detectors sensing different slurry conditions in the process feed stream, and the controller output adjusts the addition of different chemicals (additives) to the processing cell. The controller also calculates a feedback output after receiving a signal from a third detector in the tailings which monitors the extent of separation and recovery of solids from the processing cell.

Abstract: A control system having opto-electric detectors responsive to different solids concentrations and character of the solids of a slurry, the output of the detectors controlling the addition of a flocculants to the slurry to optimize coagulation of the materials in the slurry. The detectors having outputs sensing different slurry conditions with the detector outputs being processed to control the addition of different flocculants to the cell.

Abstract: Particulate material influenced by the acoustic forces in an ultrasonic standing wave is manipulated in a liquid column (16) by the use of at least two standing waves having axes extending transversely across the column at different orientations to its longitudinal axis. The nodes of the standing waves intersect within the column to give regions of greatest acoustic influence that allows a relative displacement between the particles and the liquid in a direction transverse to the axes of the standing waves. The effects of acoustic streaming can be reduced and the physical arrangement of the ultrasound apparatus in relation to the column is simplified.

Abstract: A magnetohydrostatic centrifuge of unique geometry in which an elongated separation space is provided within the bore of an elongate cylindrically shaped multipolar magnet. Separations are accomplished both with and without rotation by passing particles to be separated through the separation space within a paramagnetic or ferromagnetic fluid. Certain separations are preferably made using a quadrupolar magnet configuration with a paramagnetic fluid, others with a quadrupolar magnet and a ferromagnetic fluid, and still others, with a sextupolar magnet and a ferromagnetic fluid. Efficient use is made of the magnetic field through the use of a plurality of inner ducts creating a plurality of thin, elongate separation channels characterized by long particle dwell time and short drift distances during the separation process. Significant throughput capacity is achieved in a system in which the magnetic medium is pumped through the separator.

Abstract: An apparatus to acoustically fluidize a bed of fine particles comprises a generally box-shaped hollow chamber. An acoustic source is located at the bottom of the chamber and a convection inhibiting heater is located at the top of the chamber. An acoustic wave is directed from the source into the chamber to levitate and suspend fine particles within the chamber at determinable distances from the acoustic source according to the intensity and frequency of the acoustic wave.

Abstract: A process for programming of field decay or of increase of channel flow in field-flow fractionation which imparts improved uniformity of fractionating power which comprises an improvement in the field-flow fractionation technique which involves varying one of the parameters that affect the interaction of the sample components with the field and fluid medium in order to reduce separation time and better equalize component separation. These parameters include decreasing the field strength according to a specific power equation, or increasing the flow rate according to another power equation, or use of both parameters together.

Abstract: A tracer element for use in determining the efficiency of a heavy medium separation method which is made of aluminum, an aluminum/zinc alloy or an aluminum/magnesium alloy.

Abstract: A magnetohydrostatic centrifuge of unique geometry in which an elongated separation space is provided within the bore of an elongate cylindrically shaped multipolar magnet. Separations are accomplished both with and without rotation by passing particles to be separated through the separation space within a paramagnetic or ferromagnetic fluid. Certain separations are preferably made using a quadrupolar magnet configuration with a paramagnetic fluid, others with a quadrupolar magnet and a ferromagnetic fluid, and still others, with a sextupolar magnet and a ferromagnetic fluid. Efficient use is made of the magnetic field through the use of a plurality of inner ducts creating a plurality of thin, elongate separation channels characterized by long particle dwell time and short drift distances during the separation process. Significant throughput capacity is achieved in a system in which the magnetic medium is pumped through the separator.

Abstract: A process for automating fine coal cleaning including monitoring the operation of a flotation cell for separating coal from ash impurities by automatically detecting the coal content of the tailings from the cell and controlling the supply of additives to the cell to optimize slurry coal recovery and automatically monitoring the fluid level of the coal slurry in a dewatering filter tub to control the supply of additives to the filter tub and functioning of a dewatering filter.

Abstract: In the froth flotation of ore in a column, the froth/pulp interface level and the efficiency of the froth washing operation are controlled by determining a profile of temperatures measured in the froth layer and slurry below the interface. Temperatures are measured with temperature sensing elements immersed in the froth layer and extending to below the interface level. The measured profile is compared with a target profile and deviations are corrected by changing the tailings flowrate or the washwater flowrate to return a measured profile to the target profile. An inflection point in the profile occurs at the interface level. The inflection point in a measured profile is compared with a level set point, and a deviation from set point value is corrected by increasing or decreasing the flow of tailings whereby the interface level returns to its set point.

Abstract: Separation of particles types from a mixed population of particles in a liquid is obtained in an ultrasonic wave produced by interference between the outputs from spaced ultrasonic sources (115,118). One or more selected particle types may be separated by displacement axially along the standing wave or may be carried transversely through the standing wave or by combining both methods. The described separation can be achieved by control of flow of the liquid or giving the standing wave a drift, or by controlling the intensity or the frequency of the standing wave or by any combination of these factors. The preferred ultrasonic frequency range is between 100 kHz and 100 MHz. The process is particularly suitable for the separation of biological particles, from macromolecules to plant cells.

Abstract: A method for improving separation of the flotable phase from the non-flotable phase of a slurry of particulate material in a froth flotation machine comprising a tank, an upper outlet port for discharge of the flotable phase, and a mechanism for delivering air to the slurry in the tank to form a froth which includes a mixture of air bubbles and the flotable phase from the slurry, with the rate and selectivity of separation of the flotable phase from the slurry for predetermined size particles of the flotable phase and at a predetermined concentration of the flotable phase being dependent on the total volume and size distribution of the air bubbles generated in the slurry, the method of this invention comprising the steps of providing a quantity of slurry in the tank, generating air bubbles of relatively small size and relatively large size, and controlling the volume of air as small bubbles and the volume of air as large bubbles in response to the concentration of the flotable phase of the slurry for enhanced

Abstract: A method and apparatus for monitoring the operation of a froth flotation process comprises sensing variations in solids content of the input stream to the process, varying the dosage of flotation reagent employed in accordance with the input variations, sensing variations in solids content of at least one of the output streams after a predetermined time lapse, comparing the input and output readings with control data relating input and output solids content, and re-adjusting the dosage of flotation reagent dependent on the difference between the actual readings and the control data.

Abstract: An on-stream method and apparatus for measuring the content of a mineral constituent in a flowing slurried ore on a dry weight basis, is provided. The slurry density and flow rate, and optionally temperature, are measured to calculate a period of time during which the flowing slurry is diverted into a vessel in order to collect a target mass of ore solids therein. The time period is preferably calculated according to the following formula: ##EQU1## wherein: t is the period of time (sec);M.sub.solid is the selected target mass of the ore (g);Q.sub.slurry is the measured mass flow rate of the slurry (g/sec);p.sub.water is the density of water (g/cm.sup.3);p.sub.slurry is the measured density of the slurry (g/cm.sup.3); andp.sub.solid is the known density of the ore solids contained in the slurry (g/cm.sup.3).The slurry flow is then diverted into the vessel for the duration of the calculated time period.

Abstract: The separation of different types of particulate matter in a carrier liquid is obtained by using an ultrasonic standing wave and relying on the different acoustic responses of the different particle types. By varying the acoustic energy propagation cyclically a more effective separation rate can be obtained, with a more readily attracted particle type being subjected to a further discrimination step in each cycle. The cyclical energy variation may be in the intensity of the standing wave, e.g. using suppression means, and/or the velocity of the standing wave relative to the liquid medium, e.g. using phase control means.