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

Patent metadata

Field	Value
Publication number	US-10315202-B2
Application number	US-201514799432-A
Country	US
Kind code	B2
Filing date	Jul 14, 2015
Priority date	Jul 14, 2015
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

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.

First claim

The invention claimed is:

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.

Assignees

• IBM

Inventors

• Baldauf Julia
• Bojovschi Alexe
• Moore Stephen

Classifications

• C02F1/24

  by flotation (C02F1/465 takes precedence) · CPC title

• B03D1/1443

  Feed or discharge mechanisms for flotation tanks · CPC title

• B03D1/24 Primary

  Pneumatic {(mixing gases or vapours with liquids B01F23/20)} · CPC title

• B03D1/025

  adapted for the flotation of fines · CPC title

• B03D1/02

  Froth-flotation processes · CPC title