Gas recirculation in mineral flotation

Patent metadata

Field	Value
Publication number	US-10252276-B2
Application number	US-201615781488-A
Country	US
Kind code	B2
Filing date	Dec 7, 2016
Priority date	Dec 9, 2015
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

Abstract

An arrangement for recirculation of flotation gas in a mineral flotation process wherein the flotation gas volume fluctuations are handled by a closed pressure equalization loop including an apparatus for storing gas and adsorbing changes of gas pressure; a flushing line for connecting the pressure side of the primary gas recirculation loop to the apparatus for storing gas and adsorbing changes of gas pressure for allowing expulsion of a fraction of the flotation gas from the primary gas recirculation loop; and a suction line for connecting the suction side of the primary gas recirculation loop to the apparatus for storing gas and adsorbing changes of gas pressure, whereby the suction line comprises a pressure reducer for restricting flotation gas flow through the suction line.

First claim

The invention claimed is:

1. An arrangement for recirculation of flotation gas in a mineral flotation process, comprising:
a primary gas recirculation loop comprising:
in a pressure side of the primary gas recirculation loop a gas feed manifold for providing recirculating flotation gas into a flotation cell unit,
a gas pressurizer for pressurising recirculating flotation gas flow at said gas feed manifold,
in a suction side of the primary gas recirculation loop a gas suction manifold for collecting flotation gas from a gas collection space(s) of a mineral flotation arrangement comprising the flotation cell unit, and transferring the collected flotation gas to the gas pressurizer; wherein the arrangement further comprises:

a closed pressure equalization loop comprising:
an apparatus for storing gas and adsorbing changes of gas pressure,
a flushing line for connecting the pressure side of the primary gas recirculation loop to the apparatus for storing gas and adsorbing changes of gas pressure for allowing expulsion of a portion of the volume of the recirculating flotation gas from the primary gas recirculation loop, and
a suction line for connecting the suction side of the primary gas recirculation loop to the apparatus for storing gas and adsorbing changes of gas pressure, either directly or via the flushing line, for allowing flotation gas, present in the apparatus for storing gas and adsorbing changes of gas pressure and/or in the flushing line, to be withdrawn into the suction side of the primary gas recirculation loop through the suction line,
wherein the suction line comprises first pressure reducer for at least one of restricting flotation gas flow through the suction line thereby maintaining and providing gauge vacuum to the suction side of the primary gas recirculation loop.

2. The arrangement as claimed in claim 1 , wherein each flotation cell unit is a sealed flotation cell unit.

3. The arrangement as claimed in claim 1 , wherein the first pressure reducer further prevents uncontrolled back flow of the recirculating flotation gas from the suction side of the primary gas recirculation loop to the closed pressure equalization loop.

4. The arrangement as claimed in claim 1 , wherein the first pressure reducer provides together with the apparatus for storing gas and adsorbing changes of gas pressure, a 0.5 to 15 mbar, gauge vacuum to the suction side of the primary recirculation loop.

5. The arrangement as claimed in claim 1 , wherein the first pressure reducer is a water lock.

6. The arrangement as claimed in claim 1 , wherein the first pressure reducer comprises a gas restrictor and an interlock.

7. The arrangement as claimed in claim 6 , wherein the gas restrictor is selected from the group consisting of choke tubes, choke pipes, choke orifice plates, flow restricting membranes and flow restricting packed-bed units.

8. The arrangement as claimed in claim 6 , wherein the interlock is selected from the group consisting of no-return valves, check valves, and backflow barriers.

9. The arrangement as claimed in claim 1 , wherein the first pressure reducer is a control valve.

10. The arrangement as claimed in claim 1 , wherein the flushing line comprises a second pressure reducer for reducing the pressure of flotation gas expulsed from the pressure side of the primary gas recirculation loop to the closed pressure equalization loop to or close to the level of the pressure of the closed pressure equalization loop.

11. The arrangement as claimed in claim 10 , wherein the second pressure reducer is a control valve.

12. The arrangement as claimed in claim 1 , wherein the gas collection space(s) of a mineral flotation arrangement comprising the flotation cell units comprises the headspace(s) of the flotation cell units.

13. The arrangement as claimed in claim 12 , wherein the gas collection space(s) of a mineral flotation arrangement comprising the flotation cell units further comprises froth collection line(s) that share a common gas space with said flotation cell unit(s).

14. The arrangement as claimed in claim 12 , wherein the gas collection space(s) of a mineral flotation arrangement comprising the flotation cell units further comprises the headspace of a concentrate sump wherein mineral concentrate provided by the mineral flotation process is collected.

15. The arrangement as claimed in claim 1 , wherein the gas collection space(s) of a mineral flotation arrangement comprising the flotation cell units comprises the headspace(s) of the flotation cell units, froth collection line(s) that share a common gas space with said flotation cell unit(s) and the headspace of a concentrate sump wherein mineral concentrate provided by the mineral flotation process is collected via said froth collection line(s).

16. The arrangement as claimed in claim 1 , wherein the arrangement further comprises a bleeding line for bleeding recirculating flotation gas from at least one of the primary gas recirculation loop and the secondary gas recirculation loop.

17. The arrangement as claimed in claim 16 , wherein the closed pressure equalization loop comprises a primary bleeding line for bleeding recirculating flotation gas from the closed pressure equalization loop.

18. The arrangement as claimed in claim 17 , wherein the primary bleeding line connects from the apparatus for storing gas and adsorbing changes of gas pressure to the atmosphere and comprises means for controlling the bleed of the flotation gas from the closed pressure equalization loop and preventing uncontrolled back flow of the bled flotation gas.

19. The arrangement as claimed in claim 18 , wherein the primary bleeding line comprises a gas cleaning apparatus, for cleaning the bled flotation gas before it is released to the atmosphere.

20. The arrangement as claimed in claim 18 , wherein the means for controlling the bleed of the flotation gas from the closed pressure equalization loop and preventing uncontrolled back flow of the bled flotation gas is a control valve.

21. The arrangement as claimed in claim 16 , wherein the primary gas recirculation loop comprises a secondary bleeding line for bleeding recirculating flotation gas from the primary gas recirculation loop.

22. The arrangement as claimed in claim 21 , wherein the secondary bleeding line is in the pressure side of the of the primary gas recirculation loop.

23. The arrangement as claimed in claim 21 , wherein the secondary bleeding line comprises means for controlling the bleed of the flotation gas from the primary gas recirculation loop.

24. The arrangement as claimed in claim 23 , which further comprises a gas cleaning apparatus for cleaning the bled flotation gas before it is released to the atmosphere.

25. The arrangement as claimed in claim 23 , wherein the means for controlling the bleed of the flotation gas from the primary gas recirculation loop is a control valve.

26. The arrangement as claimed in claim 1 , wherein the arrangement further comprises at least one of means for providing process gas into the primary gas recirculation loop and the closed pressure equalization loop.

27. The arrangement as claimed in claim 26 , wherein the closed pressure equalization loop comprises means for providing process gas into the closed pressure equalization loop.

28. The arrangement as claimed in claim 1 ,
wherein the flushing line comprises a second pressure

Assignees

• Outotec Finland Oy

Inventors

• Lakanen Jukka

Classifications

• B03D1/14

  Flotation machines (devices for feeding measured quantities of reagents B01J4/02; flotation apparatus for enzymology or microbiology C12M1/09) · CPC title

• B03D1/04 Primary

  by varying ambient atmospheric pressure · CPC title

• B03D1/028 Primary

  Control and monitoring of flotation processes; computer models therefor · CPC title

• Y02P10/20

  Recycling · CPC title