Engulfed nano/micro bubbles for improved recovery of large particles in a flotation cell

• US 10,315,202 B2
• Filed: 07/14/2015
• Issued: 06/11/2019
• Est. Priority Date: 07/14/2015
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Baldauf, Julia, Bojovschi, Alexe, Moore, Stephen
• Primary Examiner(s): Lithgow, Thomas M
• Application Number:
  US14/799,432
• Publication Number:
  US 20170014834A1
• Time in Patent Office: 1,428 Days
• Field of Search: 210703-707
• CPC Class Codes: B03D 1/02 Froth-flotation processes
• CPC Class Codes: B03D 1/025 adapted for the flotation of fines
• CPC Class Codes: B03D 1/1443 Feed or discharge mechanisms for flotation tanks
• CPC Class Codes: B03D 1/16 with impellers; Subaeration machines mixing gases or vapours with liquids B01F23/20
• CPC Class Codes: B03D 1/24 Pneumatic mixing gases or vapours with liquids B01F23/20
• CPC Class Codes: C02F 1/24 by flotation C02F1/465 takes precedence

Abstract

A method of recovering particles from a liquid, a froth flotation apparatus, and a method of recovering particles in a flotation cell are disclosed. In an embodiment, the method comprises a technique of exposing the particles to first-size bubbles having a first predetermined size; the first-size bubbles adhering to the particles; and exposing the particles in a liquid, with the first-size bubbles adhering to the particles, to second-size bubbles having a second predetermined size, the second predetermined size being at least approximately ten times larger than the first predetermined size. The method further comprises the second-size bubbles adhering to the particles and engulfing the first-size bubbles on the particles; and using the second-size bubbles adhering to the particles to recover the particles from the liquid. In one embodiment a first surfactant is used to form the first-size bubbles, and a second surfactant is used to form the second-size bubbles.

Claims

1. A method of recovering particles from a liquid, comprising:

exposing the particles to first-size bubbles having a first predetermined size;

the first-size bubbles adhering to surfaces of the particles;

exposing the particles in a liquid, with the first-size bubbles adhering to the particle surfaces, to second-size bubbles having a second predetermined size, said second predetermined size being at least approximately ten times larger than the first predetermined size;

the second-size bubbles adhering to the particle surfaces and engulfing the first bubbles on the particle surfaces; and

using the second-size bubbles adhering to the particle surfaces to recover the particles from the liquid.

2. The method according to claim 1, wherein:

the exposing the particles to first-size bubbles includes using a first surfactant to form the first-size bubbles; and

the exposing the particles to second-size bubbles includes using a second surfactant to form the second-size bubbles.

3. The method according to claim 2, wherein:

the first surfactant has a first molecular length; and

the second surfactant has a second molecular length, said first molecular length being longer than the second molecular length.

4. The method according to claim 1, wherein the exposing the particles to first-size bubbles includes:

spraying the particles with a surfactant before exposing the particles to the first-size bubbles;

conducting the particles downward through a first region of a flotation cell with the surfactant sprayed on the particles; and

injecting the first-size bubbles into the first region of the flotation cell to adhere the first-size bubbles to the particles.

5. The method according to claim 4, wherein the exposing the particles to the second-size bubbles includes:

conducting the particles, with the first-size bubbles adhering to the particles, into a second region of the flotation cell; and

exposing the particles to the second-size bubbles in the second region of the flotation cell.

6. The method according to claim 4, wherein:

the spraying the particles with a surfactant includes spraying the particle with a first surfactant; and

the exposing the particles to the second-size bubbles in the second region of the flotation cell includes exposing the particles to a second surfactant in the second region.

7. The method according to claim 1, wherein:

the exposing the particles to the first-size bubbles includes exposing the particles to the first-size bubbles in a first region of the flotation cell; and

the exposing the particles to second-size bubbles includes exposing the particles to the second-size bubbles in a second region of the flotation cell.

8. The method according to claim 1, wherein:

the first-size bubbles are nano-size bubbles; and

the second-size bubbles are micron or larger size bubbles.

9. The method according to claim 8, wherein the nano-size bubbles have sizes less than approximately one micron.

10. The method according to claim 1, wherein:

the first-size bubbles are micron-sized bubbles; and

the second-size bubbles are millimeter-size bubbles.