Aluminum citrate preparations and methods

• US 5,559,263 A
• Filed: 11/16/1994
• Issued: 09/24/1996
• Est. Priority Date: 11/16/1994
• Status: Expired due to Term

• Current Assignee: Nalco Company (Ecolab, Inc.)
• Original Assignee: TIORCO, Inc. (Ecolab, Inc.)
• Inventors: Smith, Julie E.
• Primary Examiner(s): NAZARIO GONZALEZ, PORFIRIO
• Application Number:
  US08/340,585
• Time in Patent Office: 678 Days
• Field of Search: 556/183
• US Class Current: 556/183
• CPC Class Codes: C07C 51/412 by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part
• CPC Class Codes: C07C 59/265 Citric acid
• CPC Class Codes: C07F 5/069 without C-aluminium linkages
• CPC Class Codes: C09K 8/512 containing cross-linking agents

Abstract

A method for the preparation, drying and use of a stable aluminum citrate solution is disclosed. The method involves first mixing a solution containing an aluminum-chloride compound having a molar ratio of aluminum to chloride greater than about 1:3 with an aqueous solution comprising citrate. This "starter" solution is agitated at a sufficient rate to keep the slurry moving while the pH of the mixture is adjusted to a level of about 5.0 to about 9.0. The final aluminum citrate product is used to crosslink water-soluble polymer in solution for the purpose of restricting water flow in subterranean formations. The resultant aluminum citrate solution may be used either as a liquid or dried prior to shipping and using at a remote location.

Claims

1. An aluminum citrate preparation in dry form having at least about 1.1 percent chloride by weight and a molar ratio of aluminum to citrate of between about 0.5:

1 and about 2.2;

1, capable of forming a clear aqueous solution having a pH between about 5.0 and about 9.0 at a concentration of at least about 3.1 percent by weight aluminum.

2. The aluminum citrate preparation of claim 1 having an aluminum:

chloride molar ratio of at least about 1;

3.

3. The aluminum citrate preparation of claim 1 having at least about 7 percent aluminum by weight.

4. A clear aqueous aluminum citrate preparation made by solubilizing the dry aluminum citrate preparation of claim 1 in sufficient aqueous medium to form an aluminum citrate solution having at least about 3.1 weight percent aluminum.

5. A clear aqueous aluminum citrate solution having at least about 3.1 percent by weight aluminum, a pH between about 5.0 and about 9.0 and a molar ratio of aluminum to citrate at most about 2.2:

1.

6. A method for the preparation of a solution comprising aluminum citrate complex comprising the following steps:

a. providing a first aqueous solution comprising an aluminum-chloride containing complex wherein the aluminum;

chloride ratio is at least about 1;

3;

b. mixing said first solution with a second solution comprising citric acid to form a composition having a molar ratio of aluminum;

citrate at most about 2.2;

1;

c. stirring said composition of step b. continuously at a rate sufficient to keep the resultant slurry in motion;

d. adjusting the pH of said composition to between about 5.0 and about 9.0 to obtain a clear solution.

7. The method of claim 6 wherein the pH adjustment of step d. is carried out with a concentrated basic hydroxide solution of the formula MOH, where M is an alkali metal or ammonium cation.

8. The method of claim 6 wherein said aluminum-chloride-containing complex is provided in the form of aluminum chlorohydrate solution having a molar ratio of aluminum:

chloride of about 1;

2, a concentration of up to about 50 percent by weight and an aluminum concentration of up to about 12.5 percent by weight.

9. The method of claim 6 wherein said aluminum-chloride-containing complex is provided in the form of a mixture of aluminum chlorohydrate and polyaluminum chloride solution, said polyaluminum chloride solution having an activity of between about 25 percent and about 34 percent by weight, and a molar ratio of aluminum:

chloride of at least about 1;

3 aluminum;

chloride.

10. A process of making a dry aluminum citrate preparation comprising:

a. providing a first aqueous solution comprising an aluminum-chloride containing-complex wherein the aluminum;

chloride ratio is at least about 1;

3;

b. mixing said first solution with a second solution comprising citric acid to form a composition wherein the molar ratio of aluminum;

citrate is at most about 2.2;

1;

c. stirring said composition of step b. continuously at a rate sufficient to keep the resultant slurry in motion;

d. adjusting the pH of said composition to between about 5.0 and about 9.0 to obtain a clear solution;

e. drying said composition.

11. The process of claim 10 wherein said drying is carried out using drum drying means.