Systems and methods for regeneration of aqueous alkaline solution

Patent metadata

Field	Value
Publication number	US-2017033382-A1
Application number	US-201515303085-A
Country	US
Kind code	A1
Filing date	Apr 13, 2015
Priority date	Apr 13, 2014
Publication date	Feb 2, 2017
Grant date	—

Abstract

This invention is directed to regeneration of solutions comprising metal ions, and production of valuable hydroxide compounds. Specifically, the invention is related to regeneration of spent electrolyte solutions comprising metal ions (e.g. Al ions), such as electrolyte solutions used in metal/air batteries. The invention is further related to production of layered double hydroxides, and, optionally aluminum tri-hydroxide from aluminate.

First claim

What is claimed is:

1 . A system for the treatment of aqueous alkaline waste solution comprising dissolved hydroxide ions of metal A, said system comprises:
at least one reservoir; solid-liquid separation means; concentration means; agitation means; inlet for solid and liquid reagent addition; wherein said system consumes said aqueous alkaline waste solution; and wherein said system produces a regenerated aqueous alkaline solution, comprising reduced amount of dissolved hydroxide ions of metal A or wherein said system produces a regenerated aqueous alkaline solution free of dissolved hydroxide ions of metal A and wherein the system further produces metal A-containing solid products, and wherein said metal A-containing solid products comprise LDH.

2 . The system of claim 1 , wherein said metal A is aluminum and said dissolved hydroxide ions of metal A are aluminate [Al(OH) 4 − ] ions.

3 . (canceled)

4 . The system of claim 2 , wherein said metal A-containing solid products comprise aluminum-containing solid products comprising LDH and optionally ATH, LDH or a combination thereof.

5 . The system of claim 1 , further comprising temperature control means; distillation and reflux means; membrane separation means or a combination thereof.

6 . The system of claim 1 , wherein the source of said aqueous alkaline waste solution comprising dissolved hydroxide ions of metal A, is a chemical waste solution from a chemical process comprising oxidation of metal A or wherein the source of said aqueous alkaline waste solution comprising dissolved hydroxide ions of metal A, is spent electrolyte from an electrochemical process comprising oxidation of metal A.

7 . The system of claim 1 , wherein said system is modified to operate in a corrosive solution environment and in the presence of an organic co-solvent to perform the desired operations defined in claim 1 .

8 . The system of claim 1 , wherein said system is located on-board a vehicle.

9 . The system of claim 1 , wherein said system is off-board a vehicle.

10 . A method for the treatment of aqueous alkaline waste solution comprising dissolved hydroxide ions of metal A, said method comprising:
providing a system comprising:
at least one reservoir;
solid-liquid separation means;
concentration means;
agitation means;
inlet for solid and liquid reagent addition;
introducing, aqueous alkaline waste solution comprising dissolved hydroxide ions of metal A into said system; producing and separating metal A-containing solid products comprising, LDH and optionally comprising solid metal A hydroxides from said waste solution and reducing the amount of dissolved hydroxide ions of metal A in said waste solution, thus producing a regenerated aqueous alkaline solution, comprising reduced amount of dissolved hydroxide ions of metal A or free of dissolved hydroxide ions of metal A, wherein said producing and separating LDH from said waste solution comprises:
adding a metal B ions to said waste solution in said reservoir to induce precipitation of LDH;
separating said LDH from said waste solution; and
optionally drying said LDH.

11 . The method of claim 10 , wherein said metal A is aluminum and said hydroxide ions of metal A is aluminate [Al(OH) 4 − ] and said solid metal A hydroxides is ATH [Al(OH) 3 ].

12 . The method of claim 10 , wherein the source of said aqueous alkaline waste solution comprising dissolved hydroxide ions of metal A, is a chemical waste solution from a chemical process comprising oxidation of metal A or wherein the source of said aqueous alkaline waste solution comprising dissolved hydroxide ions of metal A, is spent electrolyte from an electrochemical process comprising oxidation of metal A.

13 . The method of claim 12 , wherein during said chemical or electrochemical process, metal A is dissolved in an alkaline solution such that said metal A forms dissolved metal A ions in said alkaline solution.

14 . The method of claim 10 , wherein said producing solid metal A hydroxides from said waste solution comprises separating, or precipitating and separating, said solid metal A hydroxides from said solution.

15 . The method of claim 14 , wherein said precipitating said solid metal A hydroxides is done using an electrolysis process, a dialysis process, a hydrolysis process, osmosis, phoresis or a combination thereof.

16 . The method of claim 15 , wherein said hydrolysis process comprises adding water to said waste solution, thus causing precipitation of solid metal A hydroxides.

17 . The method of claim 10 , wherein said producing solid metal A hydroxides involves the removal of dissolved hydroxide ions of metal A from said solution by decomposition of said dissolved hydroxide ions of metal A to solid metal A hydroxides and to free alkali hydroxides.

18 . (canceled)

19 . The method of claim 10 , wherein, prior to said addition of metal B ions said waste solution undergoes re-digestion, wherein said re-digestion comprises heating and agitating said waste solution to re-dissolve metal A solid hydroxide precipitate.

20 . A method for the treatment of aqueous alkaline waste solution comprising dissolved hydroxide ions of metal A and metal B ions, said method comprising precipitating LDH from said aqueous alkaline waste solution.

21 . The method of claim 20 , wherein said precipitation occurs spontaneously.

22 . The method of claim 20 , wherein the source of said aqueous alkaline waste solution comprising hydroxide ions of metal A, and metal B ions, is a metal alloy comprising metal A and metal B.

23 . The method of claim 20 , wherein said aqueous alkaline waste solution comprising hydroxide ions of metal A, and metal B ions, is formed from said metal alloy comprising metal A and metal B by a chemical or by an electrochemical process.

24 . The method of claim 23 , wherein during said chemical or electrochemical process, metal A and metal B are dissolved in an alkaline solution such that said metal A forms metal A ions and said metal B forms metal B ions in said alkaline solution.

25 . The method of claim 10 , wherein said metal B ion is selected from a group consisting of Ca, Mg, Ba, Sr and compounds of thereof.

26 . The method of claim 20 , wherein said electrochemical process is the operation of a metal-air battery.

27 . The method of claim 20 , wherein said metal-air battery comprises a cathode, an anode and an electrolyte solution, wherein said anode comprising said metal alloy comprising metals A and B.

28 . The method of claim 10 , wherein said metal B ions comprise Mg 2+ ions.

29 . The method of claim 10 , wherein said waste solution comprising NaOH, KOH, NH 4 OH, LiOH or organic base hydroxides (e.g. choline base).

30 . The method of claim 29 , wherein the concentration of said KOH or NaOH solution varies between 20 and 45 wt %.

31 . The method of claim 10 , wherein said method further comprises filtration, centrifugation, solids cake compression, washing, decanting, dewatering, drying, solvent evaporation, or a combination thereof.

32 . The method of claim 10 , wherein said LDH comprises Al.

33 . The method of claim 20 , wherein said LDH comprises meixnerite, hydrotalcite (HTC), or a combination thereof.

34

Assignees

• Alcoa Inc
• Phinergy Ltd

Inventors

• Tzidon Aviv
• Weaver Mark
• Yakupov Ilya
• Tzidon Dekel
• Yadgar Avraham
• Menegazzo Nicola

Classifications

• H01M2300/0014

  Alkaline electrolytes · CPC title

• C01F7/14

  Aluminium oxide or hydroxide from alkali metal aluminates · CPC title

• H01M12/08

  composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type · CPC title

• B60L58/16

  responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH] · CPC title

• H01M8/0693 Primary

  Treatment of the electrolyte residue, e.g. reconcentrating · CPC title