US3307697A - Apparatus for froth flotation - Google Patents

Apparatus for froth flotation Download PDF

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Publication number
US3307697A
US3307697A US294062A US29406263A US3307697A US 3307697 A US3307697 A US 3307697A US 294062 A US294062 A US 294062A US 29406263 A US29406263 A US 29406263A US 3307697 A US3307697 A US 3307697A
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United States
Prior art keywords
agitator
pulp
ring
air
baffles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US294062A
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English (en)
Inventor
Fahlstrom Per A H H Son
Oyasater Olav
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bolidens Gruvaktiebolag
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Bolidens Gruvaktiebolag
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/16—Flotation machines with impellers; Subaeration machines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1412—Flotation machines with baffles, e.g. at the wall for redirecting settling solids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1443—Feed or discharge mechanisms for flotation tanks
    • B03D1/1456—Feed mechanisms for the slurry
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1443—Feed or discharge mechanisms for flotation tanks
    • B03D1/1462—Discharge mechanisms for the froth
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1493—Flotation machines with means for establishing a specified flow pattern
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/24—Pneumatic
    • B03D1/242—Nozzles for injecting gas into the flotation tank

Definitions

  • the aeration device as an agitator, consisting of a disc attached to a vertically mounted shaft, the upper side of the disc being provided with a number of blades with or without notches between them.
  • the agitator there are, as a rule, radially placed stationary discs or ba-ffles which form an angle with the radial direction in order to counteract the rotation of the pulp.
  • the air fed to the pulp between the said agitator and a disc securely attached to the outside of the agitator is either sucked in because of the centrifugal action at the blades or, when greater quantities of air are required, it is also fed under positive pressure from an air compressor, is dispersed in the pulp partly through the mixture of air and pulp being struck against the blades, partly through the said mixture being ejected from the agitator and pressed between the surrounding discs or baffles.
  • the present invention relates to an apparatus for froth flotation'in which the above mentioned disadvantages are considerably reduced, a better and more effective dispersion and distribution of the air feed being obtained at the same time that the amount of air fed to the pulp is, per unit of volume, substantially increased, resulting in a more selective operation in the apparatus.
  • the froth flotation apparatus is of the type consisting of a trough provided with inlets for the pulp intended for flotation, outlets for tailing, and an overflow for concentrate; an agitator attached to a vertically mounted shaft in the trough, comprising a substantially circular horizontal disc which on its upper side is provided with radial or helical blades; a stationary baflle device secured around the agitator; and an air-feeding device for injecting and finely dispersing the air in the pulp.
  • the apparatus in the invention is characterised in that the air-feeding device comprises a number of annularly arranged dispersers, the dispersers being located between the outer ends of the blades and the inner sides of the baflles for the purpose of injecting air vertically into the pulp;
  • the air dispersers are arranged in a ring coaxially with the rotor shaft in a horizontal plane above the plane of the disc and arranged to eject the air substantially vertically downwards at right angles to the pulp ejected by the blades.
  • the air dispersers are preferably in the form of slots taken up in the longitudinal direction of a ring-shaped tube made of an elastomeric material, e.g. soft rubber.
  • the ring is secured in the apparatus preferably by a stiffening band of a rigid ductile material e.g. hoop iron, vulcanized into the ring, by means of which band the shape and position of the ring are maintained.
  • Thering is so placed between the agitator and the baffle device that the main part of the pulp ejected by the blades of the agitator is forced to pass it, the air being blown out from the dispersers flowing at right angles to the pulp which is quickly flowing horizontally outwards. This has proved to be of fundamental significance for maintaining an effective distribution of air with small bubbles.
  • FIG. 1 is a diagrammatic perspective view of a froth flotation apparatus according to the invention.
  • FIG. 2 shows a detail of an air disperser.
  • the froth flotation apparatus consists of a trough 1 in the form of a box-shaped respectively, for the pulp intended for flotation.
  • the froth flotation apparatus is provided with a baflle device comprising a curb of stationary, vertically standing baffles 11 the upper edges of which are welded to an iron ring 12 above the baffles.
  • the baflles can be welded to such an iron ring by their lower edges, or an iron ring can be attached to both the upper and lower edges of the baffles.
  • the baffle device rests at a number of points or brackets 13 and is held together by the iron ring 12.
  • Both the baflles 11 and the iron ring 12 can with advantage be covered with rubber.
  • one or more scrapers 15 are attached to a horizontally mounted shaft, arranged thus far is in its main parts already known.
  • An agitator is attached to the lower end of a vertically mounted shaft in the flotation trough, comprising a circular, horizontal disc 22, the upper side of which is provided with radial or helical blades 23.
  • the inner edges of the above mentioned baflles 11 lie along the periphery of a circle the diameter of which is sufliciently greater than the outer diameter of the disc 22 for a circular space to be formed between the disc 22 and the inner edges of the baffles 11.
  • a number of air dispersers for the vertical injection of air into the pulp have been arranged in this circular space above a plane in the radial extension of the disc.
  • the diffusers are suitably given the form of slots 25 (FIG.
  • annular tube 24 made of elastomeric ma-
  • the ring 24 which suitably consists of soft rubber, is placed with its under part lying very close, but not at a tangent to, a plane which can be considered to lie on the upper edges of the blades.
  • the ring 24 is suitably divided into three different sections bound to- 3 gether by T-junctions 26.
  • Flexible tubes 27, which are connected to a compressed air tube 29 with a stopcock 39 via a branch tube 28, are coupled to the T-junction.
  • An iron band 31 is vulcanized to that part of the rubber ring 24 which is turned outwards towards the baffles 11, the end of the iron ban-d extending beyond the tubing part in each section of the ring.
  • the slots are so made in the rubber tubing that they are sealed by the rubbers elasticity as long as positive pressure does not prevail inside the tubing but are opened by air under positive pressure.
  • a suitable outer diameter of the rubber tubing is between 50 and 100 mm. and the thickness of its walls between 7 and 20 mm.
  • the tubing 27 can display one single long slot or several slots in a row which for example have a length of between 7 and 20 mm. Likewise, two or three or possibly more parallel lines of such slots can be used to advantage.
  • Bubbles and fioatable particles are brought into contact with each other mainly in the zone outside the tubing and between the bafl les.
  • the air-borne particles rise out of the pulp and reach up to the froth zone of the apparatus where they are transmitted to the discharge channel 16.
  • the compressed air that is fed to the air distribution device through the pipe 29, the amount of which is regulated by the valve 30, is distribluted by means of the junction piece 28 through the tubes 27 to the T-junctions 26. An even distribution of air to the ring 24 is thereby attained.
  • the air is fed to the pulp through the slots 25 on the underside of the ring when the pressure of the air inside the ring exceeds the opening pressure of the slots and the counter-pressure of the pulp.
  • the slots are sealed because of the resiliency of the ring whereby the pulp is prevented from penetrating into the ring.
  • the air is introduced into a zone between the blades 23 and the baffles 11, at right angles to the quickly and horizontally flowing pulp. Because of the previously described vertically-horizontally circulating flow of pulp which arises with the agitator and baflies being so constructed, the pulp passes the air dispersing zone several times during its passage through the flotation trough 1. An effective distribution of air is hereby attained. The prior conditions for this are that there is pulp and that this is fed to the aeration device in such quantity that all the air can be carried away finely suspended in the pulp. This in turn implies that the finer the bubbles that are desired the greater the volume of pulp that must circulate through the air disperser.
  • An agitator which provides a horizontally outward-directed pumping action, e.g. conical discs provided with blades;
  • Annular tubing made of rubber or other material that can be vulcanized, with slots cut after vulcanization as well as being formed before vulcanization.
  • a single continuous slot as well as one or more rows of longer or shorter slots can be used;
  • Bafile device comprising a number of vertically placed, radial baffles, a obliquely placed or curved baffles in relation to the radial direction.
  • a froth flotation apparatus having a tank, inlets for the pulp intended for flotation, outlets for the tailing, an overflow for the froth, and a means for circulation and aeration of the pulp in the tank, the improvement wherein said means comprises:
  • a disc type agitator in said tank rotating about a vertical axis, said agitator moving the pulp which is adjacent thereto in a uniform, substantially horizontal, radial stream outwardly from the center of the agitator and beyond the peripheral edge thereof;
  • baflles fixed relative to said tank, said baffles being uniformly distributed around and spaced from said agitator, and positioned at substantially the same level as the agitator so as to intercept the substantially horizontal, radial stream of pulp therefrom;
  • a ring-shaped air feeding element substantially coaxial with said agitator and said baffles, said element in a radial direction being positioned between said baffles and the periphery of said agitator, but in an axial direction being offset from said agitator, said ring-shaped element further having air feeding openings spaced entirely therearound which are directed toward a plane coincident with the plane of said agitator so as to direct a uniform curtain of air substantially perpendicular to the flow path of the radial stream of pulp from said agitator;
  • disc type agitator consists of a substantially circular, horizontal disc, the upper side of which is provided with radial blades.
  • the air feeding element has the form of an annular tube made of an elastomeric material such as soft rubber, provided with rows of short slots in the longitudinal direction of the tube.
  • Apparatus according to claim 1 characterized by the fastening of the elastomeric air feeding element in the apparatus by attachment to a rigid ring of ductile material such as iron, vulcanized to the said air feeding element.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biotechnology (AREA)
  • Paper (AREA)
  • Mixers Of The Rotary Stirring Type (AREA)
US294062A 1962-08-03 1963-07-10 Apparatus for froth flotation Expired - Lifetime US3307697A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE854962 1962-08-03

Publications (1)

Publication Number Publication Date
US3307697A true US3307697A (en) 1967-03-07

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Family Applications (1)

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US294062A Expired - Lifetime US3307697A (en) 1962-08-03 1963-07-10 Apparatus for froth flotation

Country Status (3)

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US (1) US3307697A (ja)
FI (1) FI40706B (ja)
GB (1) GB973396A (ja)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3490589A (en) * 1968-06-17 1970-01-20 Cities Service Athabasca Inc Controlled phase separation vessel
US3909413A (en) * 1972-02-21 1975-09-30 Mitsui Mining & Smelting Co Flotation machine
US4624777A (en) * 1983-11-18 1986-11-25 Outokumpu Oy Flotation machine
US4681711A (en) * 1986-05-06 1987-07-21 Eaton John M Method and apparatus for aeration of wastewater lagoons
WO1989012496A1 (en) * 1988-06-20 1989-12-28 General Signal Corporation Mixing apparatus

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2243301A (en) * 1938-12-15 1941-05-27 Morse Bros Machinery Company Aeration apparatus
US2626052A (en) * 1947-04-11 1953-01-20 Carbonnier Robert Flotation machine
US3063689A (en) * 1957-10-02 1962-11-13 Distillers Co Yeast Ltd Gas/liquid contacting means

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2243301A (en) * 1938-12-15 1941-05-27 Morse Bros Machinery Company Aeration apparatus
US2626052A (en) * 1947-04-11 1953-01-20 Carbonnier Robert Flotation machine
US3063689A (en) * 1957-10-02 1962-11-13 Distillers Co Yeast Ltd Gas/liquid contacting means

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3490589A (en) * 1968-06-17 1970-01-20 Cities Service Athabasca Inc Controlled phase separation vessel
US3909413A (en) * 1972-02-21 1975-09-30 Mitsui Mining & Smelting Co Flotation machine
US4624777A (en) * 1983-11-18 1986-11-25 Outokumpu Oy Flotation machine
AU571281B2 (en) * 1983-11-18 1988-04-14 Outokumpu Oy Flotation machine
US4681711A (en) * 1986-05-06 1987-07-21 Eaton John M Method and apparatus for aeration of wastewater lagoons
WO1989012496A1 (en) * 1988-06-20 1989-12-28 General Signal Corporation Mixing apparatus

Also Published As

Publication number Publication date
GB973396A (en) 1964-10-28
FI40706B (ja) 1969-01-31

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