Process for the production of dibasic magnesium hypochlorite

• US 4,380,533 A
• Filed: 07/08/1981
• Issued: 04/19/1983
• Est. Priority Date: 03/12/1980
• Status: Expired due to Fees

• Current Assignee: OLIN Corporation
• Original Assignee: OLIN Corporation
• Inventors: Wojtowicz, John A.
• Primary Examiner(s): Hearn, Brian E.
• Application Number:
  US06/281,534
• Time in Patent Office: 650 Days
• Field of Search: 423/473, 423/474, 423/164, 423/636
• US Class Current: 423/473
• CPC Class Codes: C01B 11/066 Magnesium hypochlorite

Abstract

A process is described for the production of dibasic magnesium hypochlorite which comprises reacting a magnesium salt with an aqueous slurry of a crystalline hypochlorite salt in a reaction mixture containing a chloride ion source. The aqueous slurry has a solids content of from about 10 to about 90 percent by weight of a hypochlorite salt such as an alkali metal hypochlorite or calcium hypochlorite. The process provides a dibasic magnesium hypochlorite product which is readily separated.

Dibasic magnesium hypochlorite, Mg(OCl)₂.2Mg(OH)₂ is useful in bleaching and sanitizing applications.

Claims

1. A process for the production of dibasic magnesium hypochlorite which comprises reacting a magnesium salt, an aqueous slurry of a crystalline hypochlorite salt selected from the group consisting of alkali metal hypochlorites and calcium hypochlorite, and a chloride ion source to form a reaction mixture, said slurry having a solids content of from about 10 to about 90 percent by weight of said hypochlorite salt, evolving chlorine gas from said reaction mixture, the molar ratio of magnesium ion to the hypochlorite ion being from about 0.4:

1 to about 2.0;

1.0 and recovering said dibasic magnesium hypochlorite therefrom.

2. The process of claim 1 which said hypochlorite salt is calcium hypochlorite.

3. The process of claim 1 in which said hypochlorite salt is an alkali metal hypochlorite selected from the group consisting of lithium hypochlorite and sodium hypochlorite.

4. The process of claim 2 in which said magnesium salt is added as an aqueous slurry and said reaction mixture has a total water content of no more than about 60 percent by weight.

6. The process of claim 2 or claim 5 in which said magnesium salt is selected from the group consisting of magnesium acetate, magnesium carbonate, magnesium chlorate, magnesium perchlorate, magnesium chloride, magnesium chromate, magnesium nitrate, magnesium sulfate, and hydrates thereof.

7. The process of claim 6 in which said chloride ion source is selected from the group consisting of alkali metal chlorides, magnesium chloride, and calcium chloride.

8. The process of claim 7 in which said slurry contains from about 35 to about 65 percent by weight of said hypochlorite salt.

9. The process of claim 8 in which said magnesium salt is magnesium chloride or magnesium nitrate.

13. the process of claim 6 in which said reaction mixture is purged with an inert gas.

15. The process of claim 1 in which the rate of addition of hypochlorite ion is at least 2 gram moles per kilogram of magnesium salt per hour.

16. The process of claim 1 or claim 5 in which said molar ratio of magnesium ion to the hypochlorite ion is from about 0.75:

1.0 to about 1.0;

1.0.

5. A continuous process for the production of dibasic magnesium hypochlorite which comprises:

a. admixing a solid magnesium salt with an aqueous slurry having a solids content of from about 20 to about 80 percent by weight of calcium hypochlorite, and a chloride ion source, the molar ratio of the magnesium ion to the hypochlorite ion being from about 0.4;

1.0 to about 2.0;

1.0, to produce a reaction mixture containing dibasic magnesium hypochlorite, chlorine gas, and a solution containing dissolved calcium and magnesium values;

b. evolving chlorine gas from said reaction mixture;

c. separating said solid dibasic magnesium hypochlorite from said solution;

d. treating said solution with an alkali metal hydroxide to form a slurry of magnesium hydroxide in a solution containing dissolved calcium values; and

e. separating said magnesium hydroxide from said solution.

10. The process of claim 5 in which said magnesium hydroxide is reacted with an acid to form a magnesium salt and returning said magnesium salt to step a.

11. The process of claim 10 in which said solution containing dissolved calcium values is treated with an alkali metal hydroxide to form a slurry of calcium hydroxide in a solution and recovering said calcium hydroxide from said solution.

12. A process for the production of dibasic magnesium hypochlorite which comprises reacting an anhydrous solid magnesium salt with an aqueous slurry of a crystalline hypochlorite salt selected from the group consisting of alkali metal hypochlorites and calcium hypochlorite and a chloride ion source to form a reaction mixture, said slurry having a solids content of from about 10 to about 90 percent by weight of said hypochlorite salt and a molar ratio of magnesium ion to hypochlorite ion of from about 0.4:

1.0 to about 2.0;

l.0, evolving chlorine gas from said reaction mixture, and recovering said dibasic magnesium hypochlorite therefrom.

14. A continuous process for the production of dibasic magnesium hypochlorite which comprises:

a. admixing a solid magnesium salt with an aqueous slurry having a solids content of from about 20 to about 80 percent by weight of calcium hypochlorite, and a chloride ion source to produce a reaction mixture containing dibasic magnesium hypochlorite, chlorine gas, and a solution containing dissolved calcium and magnesium values;

b. evolving chlorine gas from said reaction mixture;

c. separating said solid dibasic magnesium hypochlorite from said solution;

d. treating said solution with an alkali metal hydroxide to form a slurry of magnesium hydroxide in a solution containing dissolved calcium values;

e. separating said magnesium hydroxide from said solution; and

f. reacting said magnesium hydroxide with an acid to form a magnesium salt and returning said magnesium salt to said reaction mixture.