Classifications

• • 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
  • B03D1/02—Froth-flotation processes
• • 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
  • B03D1/1475—Flotation tanks having means for discharging the pulp, e.g. as a bleed stream
• • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S210/00—Liquid purification or separation
  • Y10S210/902—Materials removed
  • Y10S210/911—Cumulative poison
  • Y10S210/912—Heavy metal

Definitions

• the present invention relates to an improvement brought about in the separation and the recovery of solids from liquids containing them and using the ion flotation process.
• the invention also relates to the means for implementing this improvement.
• Ion flotation is a known technique aimed at eliminating certain ions, in particular metal cations, from a solution containing them.
• This technique consists in introducing into the solution to be treated, a surfactant, called a collector, the role of which is to complex and insolubilize the ion which one wishes to separate and to entrain, within this liquid, in an upward movement, said complex on the surface of this liquid and to recover it on this surface.
• the present invention aims to overcome these drawbacks and to provide a simple and economical method and means allowing:
• the Applicant has unexpectedly found that by subjecting a fraction of the liquid to be treated containing the solid to be recovered to a process consisting in admitting this fraction into a device adapted to lower its pressure, in bringing the resulting flow into contact with a gas admitted into this flow at very high speed and at low incidence, in bringing the two fluids together under conditions of expansion for make a fine emulsion and take up said emulsion by raising the pressure while maintaining the resulting pressure at a level lower than that corresponding to the initial pressure of the admitted liquid, and injecting said emulsion into a volume of the liquid to be treated, we obtained on the surface of this volume, and in a quiet zone, an accumulation of the desired solid practically free from the initial liquid phase.
• liquid to be treated is meant any suspension of the "collector-ion" precipitate in the liquid phase.
• the ability of the solid to float is not altered by modification, for example of its particle size, neither during its passage through the device nor by untimely turbulence within the liquid mass. .
• the Applicant has found that the system applies particularly well when the liquid to be treated is a concentrated solution of a mineral acid such as for example phosphoric acid; the yield expressed as a percentage of the quantity of solid separated in a single operation turns out to be at least 307. in the case of the phosphoric medium.
• a mineral acid such as for example phosphoric acid
• the invention provides a recycling circuit in the system allowing total recovery of the desired solid.
• a pre-treatment tank for the solution to be treated this pre-treatment consisting in introducing into it a surfactant (collector) so as to form a suspension, this medium being maintained under stirring by means of an agitator 2 of any known type, and in 5 a flotation cell supplied with this suspension by any suitable means.
• This cell is then made to pass through a non-turbulent ascenti ⁇ nnel current intended to convey the solid towards the surface of the suspension, this current being obtained in the following way: by means of a pump 3, the medium coming from the tank 1 in an apparatus 4 of the type which is the subject, for example, of French patent 2,484,862 and comprising from upstream to downstream, a converging conduit for supplying said medium, a gas injection stage produced so that this gas be admitted at very high speed under a relatively low incidence; this injection stage is immediately followed by an expansion stage constituted by an enclosure whose walls are non-converging which opens into a clearly divergent zone in communication, possibly, with an enclosure for recovering and / or recycling the gas.
• the device 4 is shown placed at the base of the cell 5. It can just as advantageously be placed above the latter.
• a population of stable, fine, numerous bubbles is obtained which is capable of transporting the solid contained in cell 5 to the surface 5a of the liquid phase.
• This solid collects on this surface practically free of entrained liquid; it is recovered by any suitable means at 6 to be sent to a storage bin 7.
• the liquid medium is returned, via line 8, to the device 4 by the circuit designated by the references 9-10-11 , possibly using a pump 3a.
• the liquid medium is recovered in the recovery tank 12.
• the method and the device according to the invention are particularly advantageous for the recovery of elements such as uranium, zirconium. cadmium, arsenic, rare earths, etc. contained in wet phosphoric acid with minimum entrainment of said acid.
• Example 1 the method and the device according to the invention can be applied to a flotation cell of the type described in French patent 2,354,820 previously cited.
• a flotation cell of the type described in French patent 2,354,820 previously cited.
• Such a cell in which the original gas ejector is replaced by a device according to the invention can then operate under clearly different and more economical conditions than those for which it is designed.
• the following examples will better illustrate the scope and interest of the invention: Example 1
• the precipitation is carried out as in Example 1 by carrying out a pre-reduction of the uranium (before the introduction of the collector into the acid).
• the conditions of flotation of the precipitate are the same as in Example 2 with an R ratio equal to 4.2.
• the effectiveness of the device for the flotation of the precipitate is also excellent, of the order of 90% after one pass and 98% after recycling the acid solution for 5 minutes.
• the uranium content eliminated by this implementation of the process is thus greater than 85% after one pass and equal to 95% after 5 minutes of recycling.
• the acid treated is a wet industrial phosphoric acid containing 30% P 2 O 5 and containing approximately 40 mg / l as Cd and 115 mg / l as uranium.
• the flotation equipment used is commercial pilot equipment (WEMCO Depurator type) with four in-line cells of approximately 30 liters each; the device (4) of the appended figure is then positioned vertically above the liquid phase loaded with solid circulating in the cell, the outlet of the device being located below the surface of the liquid; the tests were carried out with only two of the cells. These two cells were equipped with the device according to the invention to replace the original ejector.
• the flotation conditions are as follows at the device (4):

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Biotechnology (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Separation Of Suspended Particles By Flocculating Agents (AREA)
• Physical Water Treatments (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9310119

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (9)

Citations (9)

Family Cites Families (11)

• 1984
  • 1984-11-30 FR FR8418301A patent/FR2574002B1/fr not_active Expired
• 1985
  • 1985-06-18 MA MA20685A patent/MA20458A1/fr unknown
  • 1985-06-19 DE DE8585903006T patent/DE3572604D1/de not_active Expired
  • 1985-06-19 WO PCT/FR1985/000163 patent/WO1986003142A1/fr not_active Ceased
  • 1985-06-19 US US06/893,330 patent/US4844873A/en not_active Expired - Fee Related
  • 1985-06-19 EP EP85903006A patent/EP0203076B1/fr not_active Expired
  • 1985-06-19 JP JP60502741A patent/JPS62500918A/ja active Granted
• 1986
  • 1986-07-30 OA OA58913A patent/OA08372A/xx unknown

Patent Citations (9)

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