Sodium zirconium carbonate and zirconium basic carbonate and methods of making the same

• US 6,627,164 B1
• Filed: 11/28/2000
• Issued: 09/30/2003
• Est. Priority Date: 11/28/2000
• Status: Expired due to Term

• Current Assignee: Renal Solutions, Inc. (Fresenius Medical Care AG)
• Original Assignee: Renal Solutions, Inc. (Fresenius Medical Care AG)
• Inventors: Wong, Raymond J.
• Primary Examiner(s): Bos, Steven
• Assistant Examiner(s): Kuhar, Anthony
• Application Number:
  US09/723,396
• Time in Patent Office: 1,036 Days
• Field of Search: 423/69, 423/84, 423/179, 423/184, 423/186, 423/209, 423/419.1, 423/420.2, 423/421, 423/71
• US Class Current: 423/71
• CPC Class Codes: A61M 1/1696 with dialysate regeneration
• CPC Class Codes: A61P 7/08 Plasma substitutes; Perfusion solutions; Dialytics or haemodialytics; Drugs for electrolytic or acid-base disorders, e.g. hypovolemic shock artificial tears A61P27/04
• CPC Class Codes: B01J 20/0211 Compounds of Ti, Zr, Hf
• CPC Class Codes: B01J 20/0277 Carbonates of compounds other than those provided for in B01J20/043
• CPC Class Codes: B01J 20/0292 Phosphates of compounds other than those provided for in B01J20/048
• CPC Class Codes: B01J 20/043 Carbonates or bicarbonates, e.g. limestone, dolomite, aragonite
• CPC Class Codes: B01J 20/08 comprising aluminium oxide or hydroxide; comprising bauxite
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 20/28052 Several layers of identical or different sorbents stacked in a housing, e.g. in a column
• CPC Class Codes: B01J 20/3234 Inorganic material layers
• CPC Class Codes: B01J 2220/42 Materials comprising a mixture of inorganic materials materials coated or impregnated on a carrier B01J20/32
• CPC Class Codes: B01J 2220/62 In a cartridge
• CPC Class Codes: C01G 25/00 Compounds of zirconium
• CPC Class Codes: C01G 25/006 Compounds containing, besides zirconium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2006/82 water content

Abstract

A method of making sodium zirconium carbonate is described which involves forming a mixture of zirconium oxychloride with soda ash and then heating at a sufficient temperature and for a sufficient time to form the sodium zirconium carbonate. Subsequent washing and filtration steps can further form parts of this process. A novel sodium zirconium carbonate is further described which contains from about 2 wt % to about 5 wt % Na⁺; from about 44 wt % to about 50 wt % ZrO₂; from about 12 wt % to about 18 wt % CO₃²⁻; and from about 32 wt % to about 35 wt % H₂O.

Claims

1. A method of making a sodium zirconium carbonate free of OH groups comprising heating a mixture of zirconium oxychloride and soda ash at a sufficient temperature and for a sufficient time to form said sodium zirconium carbonate free of OH groups.

2. The method of claim 1, further comprising, prior to said heating, agitating the zirconium oxychloride and soda ash to form a solution mixture at ambient temperature.

3. The method of claim 1, wherein said soda ash is in the form of an aqueous slurry or solution.

4. The method of claim 1, wherein said zirconium oxychloride and soda ash are present in a weight ratio of from about 3.0:

1 to about 4.0;

1.

5. The method of claim 4, wherein said weight ratio is from about 3.5:

1 to about 4.0;

1.

6. The method of claim 4, wherein said weight ratio is about 3.6:

1.

7. The method of claim 1, wherein said zirconium oxychloride is in the form of a powder or solution.

8. The method of claim 1, wherein said sufficient temperature is the boiling temperature of the mixture of zirconium oxychloride and soda ash.

9. The method of claim 8, wherein the heating occurs for about 2 hours.

10. The method of claim 1, wherein said temperature is from about 150°

F. to about 250°

F.

11. The method of claim 1, further comprising, after said heating, filtering off the sodium zirconium carbonate.

12. The method of claim 11, further comprising, after filtering, washing any chloride or any impurities from said sodium zirconium carbonate.

13. The method of claim 1, further comprising, after heating, titrating an alkaline slurry comprising said sodium zirconium carbonate with at least one acidic agent to obtain a pH of less than about 7.0.

14. The method of claim 13, wherein said pH is from about 3.5 to about 6.0.

15. The method of claim 13, wherein said pH is about 6.

16. The method of claim 13, further comprising, after titrating, filtering off said sodium zirconium carbonate and washing said sodium zirconium carbonate.

17. The method of claim 16, further comprising, after washing, drying said sodium zirconium carbonate.

18. The method of claim 17, wherein said drying occurs for a sufficient time to form a free flowing powder.

19. The method of claim 17, wherein after said drying, said sodium zirconium carbonate has a moisture content of from about 10% LOD to about 60% LOD.

20. The method of claim 19, wherein said moisture content is from about 30% LOD to about 35% LOD.

21. The method of claim 18, wherein said sodium zirconium carbonate has an average particle size of from about 30 microns to about 50 microns.

22. The method of claim 1, wherein said heating occurs at a heating rate of from about 0.5°

F. to about 1°

F./minute until boiling temperature of said mixture.

27. The method of claim 1, wherein said zirconium oxychloride and soda ash are mixed at a temperature of from about 40°

F. to about 110°

F.

28. The method of claim 1, wherein said sodium zirconium carbonate has a formula NaZrO₂CO₃.nH₂O.

23. A method of making sodium zirconium carbonate comprising mixing zirconium oxychloride with soda ash and agitating to form a solution mixture at ambient temperatures;

heating said mixture of zirconium oxychloride and soda ash at a sufficient temperature and for a sufficient time to form said sodium zirconium carbonate, wherein said sufficient temperature is the boiling temperature of the mixture of zirconium oxychloride and soda ash;

after said heating, filtering off the sodium zirconium carbonate;

after filtering, washing any chloride or any impurities from said sodium zirconium carbonate;

titrating an alkaline slurry comprising said sodium zirconium carbonate with at least one acidic agent to obtain a pH of less than about 7.0;

after titrating, filtering off said sodium zirconium carbonate and washing said sodium zirconium carbonate; and

after washing, drying said sodium zirconium carbonate.

24. A sodium zirconium carbonate comprising from about 2 wt % to about 5 wt % Na⁺;

from about 44 wt % to about 50 wt % ZrO₂;

from about 12 wt % to about 18 wt % CO₃²⁻

; and

from about 32 wt % to about 35 wt % H₂O, based on the weight of the sodium zirconium carbonate.

25. The sodium zirconium carbonate of claim 24, wherein said sodium zirconium carbonate satisfies ANSI/AAMI RD-5-1992 standard on extractable toxic impurities.

26. The sodium zirconium carbonate of claim 24, wherein said sodium zirconium carbonate satisfies at least one of the following characteristics:

a phosphate adsorption having a minimum capacity of from about 30 to about 35 mg/PO₄-P/gm SCZ;

a minimum HCO₃⁻

content of from about 2 to about 4 mEq HCO₃⁻

gm SCZ;

a leachable Na⁺ content of from about 1.5 to about 2.0 mEq Na⁺/gm SCZ;

or a pH range of titrated sodium zirconium carbonate of from about 6 to about 7.

29. A method of making a sodium zirconium carbonate comprising:

heating a mixture of zirconium oxychloride and soda ash at a sufficient temperature and for a sufficient time to form said sodium zirconium carbonate; and

titrating an alkaline slurry comprising said sodium zirconium carbonate with at least one acidic agent to obtain a pH of less than about 7.0.

30. A method of making a sodium zirconium carbonate comprising:

heating a mixture of zirconium oxychloride and soda ash at a sufficient temperature and for a sufficient time to form said sodium zirconium carbonate, wherein said heating occurs at a heating rate of from about 0.5°

F. to about 1°

F./minute until boiling temperature of said mixture.