Zirconium basic carbonate and methods of making the same

• US 7,101,519 B2
• Filed: 08/10/2004
• Issued: 09/05/2006
• 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): Hendrickson, Stuart L.
• Assistant Examiner(s): RAETZSCH, ALVIN T
• Application Number:
  US10/914,954
• Publication Number:
  US 20050031523A1
• Time in Patent Office: 756 Days
• Field of Search: 423/85, 423/84, 423/420.2, 423/419.1
• US Class Current: 423/85
• 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

Methods of making zirconium basic carbonate are further described which involve titrating an aqueous slurry of sodium zirconium carbonate to a pH of from about 3.5 to about 4.0 with an acidic agent wherein the sodium zirconium carbonate has a moisture content of from about 15% to about 25% LOD in solid form. The process further involves washing the aqueous slurry containing the formed zirconium basic carbonate with water. A novel zirconium basic carbonate is further disclosed which has a minimum adsorption 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; and/or a pH range of titrated sodium zirconium carbonate of from about 6 to about 7.

Claims

1. A method of making a zirconium basic carbonate comprising titrating an aqueous slurry of sodium zirconium carbonate to a pH of from about 3.5 to about 4.0 with a acidic agent, wherein said sodium zirconium carbonate has a moisture content of from about 15% to about 25% LOD in solid form;

and washing said aqueous slurry containing the zirconium basic carbonate with water.

2. The method of claim 1, further comprising recovering said zirconium basic chloride wet powder from said slurry.

3. The method of claim 2, wherein said recovery occurs by a vacuum filtration.

4. The method of claim 2, wherein said recovery occurs by centrifuging.

7. The method of claim 1, wherein said sodium zirconium carbonate is formed by heating a mixture of zirconium oxychloride and soda ash at a sufficient temperature and for a sufficient time to form said sodium zirconium carbonate.

8. The method of claim 7, further comprising, after heating, filtering off the sodium zirconium carbonate and washing any chloride or 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 below about 7.0;

filtering off said sodium zirconium carbonate and washing said sodium zirconium carbonate; and

drying said sodium zirconium carbonate for a sufficient time to obtain a free flowing powder;

wherein after drying, sodium zirconium carbonate has a moisture content of from about 10% LOD to about 60% LOD.

5. A zirconium basic carbonate having:

Na⁺ of less than about 1000 ppm;

a ZrO₂ wt % of from about 35 wt % to about 40 wt %;

and a CO₃²⁻

of from about 8 wt % to about 10 wt %, based on the weight of the zirconium basic carbonate.

6. The zirconium basic carbonate of claim 5, wherein said zirconium basic carbonate has about 0 wt % SO₄²⁻

and about 0 wt % Cl⁻

.