Method for the preparation of liquid aluminum citrate

Claim 1

A method for the preparation of an aqueous solution of an aluminum citrate complex which consists essentially of the following steps: (a) providing an aqueous solution of AlCl 3 containing up to about 34 weight % AlCl 3 ; (b) combining the AlCl 3 solution with an aqueous solution of citric acid containing up to about 50 weight % citric acid, while vigorously agitating the resultant solution, to form an aluminum citrate solution having a mole ratio of aluminum ion to citric acid molecule of from about 1.5:1 to 2.0:1, said AlCl 3 solution being provided in an amount sufficient to form an aluminum citrate solution containing from 1 up to about 3 weight % aluminum; and (c) adding a basic hydroxide of the formula MOH where M is an alkali metal or ammonium cation to the aluminum citrate solution, while continuing to agitate the solution and while maintaining its temperature within the range of from 20° C. to 90° C., in sufficient quantity to raise the pH of the solution to a level of from 5.5 to 7.5.

Claim 2

A method for the preparation of an aqueous solution of an aluminum citrate complex which consists essentially of the following steps: (a) providing an aqueous solution of AlCl 3 containing up to about 34 weight % AlCl 3 ; (b) combining the AlCl 3 solution with an aqueous solution of citric acid containing up to about 50 weight % citric acid, while vigorously agitating the resultant solution, to form an aluminum citrate solution having a mole ratio of aluminum ion to citric acid molecule of from about 1.5:1 to 2.0:1, said AlCl 3 solution being provided in an amount sufficient to form an aluminum citrate solution containing from 1 up to about 3 weight % aluminum; and (c) adding a basic hydroxide of the formula MOH where M is an alkali metal or ammonium cation to the aluminum citrate solution, while continuing to agitate the solution and while maintaining its temperature within the range of from 20° C. to 90° C., in sufficient quantity to raise the pH of the solution to a level of from 5.5 to 7.5.

Claim 8

A method for the preparation of a stable liquid aluminum citrate which consists essentially of the following steps: (a) providing an aqueous solution of aluminum chloride containing up to about 34% (w/w) of aluminum chloride; (b) combining the aluminum chloride solution with an aqueous solution of citric acid containing up to about 50% (w/w) citric acid while providing vigorous agitation to form a solution of aluminum citrate containing from 1 to about 3 weight % aluminum and having a mole ratio of aluminum ion to citric acid molecule of from about 1.5:1 to about 2:1; and (c) adding a 50% (w/w) solution of sodium hydroxide to the aluminum citrate solution, while continuing to provide vigorous agitation and maintaining the temperature of the resultant at a level of from 40° C. to 60° C., to raise the pH to a level of from 6.0 to 7.0.

Claim 9

A method for the preparation of a stable liquid aluminum citrate which consists essentially of the following steps: (a) providing an aqueous solution of aluminum chloride containing up to about 34% (w/w) of aluminum chloride; (b) combining the aluminum chloride solution with an aqueous solution of citric acid containing up to about 50% (w/w) citric acid while providing vigorous agitation to form a solution of aluminum citrate containing from 1 to about 3 weight % aluminum and having a mole ratio of aluminum ion to citric acid molecule of from about 1.5:1 to about 2:1; and (c) adding a 50% (w/w) solution of sodium hydroxide to the aluminum citrate solution, while continuing to provide vigorous agitation and maintaining the temperature of the resultant at a level of from 40° C. to 60° C., to raise the pH to a level of from 6.0 to 7.0.