Method for improving overflow clarity in production of coal

Patent metadata

Field	Value
Publication number	US-11155478-B2
Application number	US-201715648891-A
Country	US
Kind code	B2
Filing date	Jul 13, 2017
Priority date	Jul 15, 2016
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

A transitional treatment composition and methods of treating coal refuse are provided. The transitional treatment composition comprises an anionic acrylate-acrylamide copolymer having from about 30 mole percent to about 50 mole percent (meth)acrylate, from about 50 mole percent to about 70 mole percent (meth)acrylamide, and a reduced specific viscosity of from about 18 dL/g to about 30 dL/g. The transitional treatment composition can be made down in an aqueous liquid.

First claim

The invention claimed is:

1. A composition consisting of:
a coal refuse comprising 20 wt % to 80 wt % non-expandable clay; and
an anionic acrylate-acrylamide copolymer having from about 36 mole percent to about 44 mole percent (meth)acrylate and about 56 mole percent to about 64 mole percent (meth)acrylamide, and a reduced specific viscosity of from about 22 dL/g to about 28 dL/g.

2. The composition of claim 1 , wherein the composition is aqueous slurry.

3. The composition of claim 1 , wherein the (meth)acrylate is acrylate.

4. The composition of claim 1 , wherein the (meth)acrylamide is acrylamide.

5. The composition of claim 1 , wherein the anionic acrylate-acrylamide copolymer has a weight average molecular weight of from about 4 million to about 7 million Daltons.

6. The composition of claim 5 , wherein the anionic acrylate-acrylamide copolymer has a weight average molecular weight of from about 5 million to about 7 million Daltons.

7. The composition of claim 6 , wherein the anionic acrylate-acrylamide copolymer has a weight average molecular weight of from about 6 million to about 7 million Daltons.

8. The composition of claim 1 , wherein the non-expandable clay comprises illite, kaolinite, or a combination thereof.

9. A method of treating coal refuse consisting of:
combining an anionic acrylate-acrylamide copolymer having from about 36 mole percent to about 44 mole percent (meth)acrylate, from about 56 mole percent to about 64 mole percent (meth)acrylamide, and a reduced specific viscosity of from about 22 dL/g to about 28 dL/g and coal refuse comprising 20 wt % to 80 wt % non-expandable clay.

10. A method of separating water from coal refuse consisting of:
combining an anionic acrylate-acrylamide copolymer having from about 36 mole percent to about 44 mole percent (meth)acrylate, from about 56 mole percent to about 64 mole percent (meth)acrylamide, and a reduced specific viscosity of from about 22 dL/g to about 28 dL/g and coal refuse comprising 20 wt % to 80 wt % non-expandable clay downstream of a coal flotation operation to form treated coal refuse; and
allowing the treated coal refuse to stand in a settling vessel to form a top layer comprising water having turbidity less than about 200 NTU, and a bottom layer comprising settled treated coal refuse; and optionally, transferring at least a portion of a layer from the settling vessel.

11. The method of claim 10 , further comprising transferring at least a portion of the bottom layer from the settling vessel.

12. The method of claim 10 , further comprising transferring at least a portion of the top layer from the settling vessel.

13. The method of claim 12 , wherein the portion of the top layer is transferred from the settling vessel via overflow.

14. The method of claim 10 , wherein the top layer has a turbidity less than about 100 NTU.

15. The method of claim 10 , wherein the top layer has a turbidity less than about 80 NTU.

16. The method of claim 10 , wherein the top layer has a turbidity less than about 60 NTU.

17. The method of claim 10 , wherein the bottom layer settles at a rate of from about 10 to about 15 inches per minute.

18. The method of claim 10 , wherein the anionic acrylate-acrylamide copolymer and the coal refuse are combined at a plurality of feed points of the anionic acrylate-acrylamide copolymer.

19. The method of claim 18 , wherein the plurality of feed points is at least three feed points.

Assignees

• Ecolab Usa Inc

Inventors

• Greulich Christopher Ryan
• Mcdonald Kevin
• Cheng Weiguo

Classifications

• C02F2001/007

  Processes including a sedimentation step · CPC title

• C02F2101/10

  Inorganic compounds · CPC title

• C02F1/56 Primary

  Macromolecular compounds · CPC title

• C08F220/56

  Acrylamide; Methacrylamide · CPC title

• B03D3/06

  Flocculation · CPC title