Treatment of azide containing waste

• US 5,073,273 A
• Filed: 05/22/1991
• Issued: 12/17/1991
• Est. Priority Date: 05/22/1991
• Status: Expired due to Fees

• Current Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Kraft, Morton L., Gupta, Raj K., Coleman, William B.
• Primary Examiner(s): Silverman, Stanley S.
• Assistant Examiner(s): Nessler, Cynthia L.
• Application Number:
  US07/703,910
• Time in Patent Office: 209 Days
• Field of Search: 210/900, 210/760, 210/761, 210/753, 210/903, 210/766, 423/395
• US Class Current: 210/760
• CPC Class Codes: C02F 1/78 with ozone C02F1/4672 takes precedence
• CPC Class Codes: Y10S 210/90 Ultra pure water, e.g. conductivity water
• CPC Class Codes: Y10S 210/903 Nitrogenous

Abstract

A process for treating a gas generating material waste containing an alkali metal azide comprising the steps of preparing an alkaline aqueous solution containing the waste, treating the alkaline aqueous solution with a gaseous stream of ozone under conditions effective to oxidize the alkali metal azide to nitrogen and alkali metal nitrate, and then recovering the nitrate.

Claims

1. A process for the treatment of a waste containing an azide having he formula XN₃, where X is an alkali metal, comprising the steps of:

preparing an alkaline aqueous slurry containing said alkali metal azide; and

treating said alkaline aqueous slurry with a gaseous stream of ozone under conditions effective to oxidize the alkali metal azide to nitrogen and an alkali metal nitrate.

2. The process of claim 1 wherein said waste also contains water insoluble solids, and further including the step of separating said water insoluble solids from the alkali metal nitrate after ozonation.

3. The process of claim 2 wherein said water insoluble solids comprise a metal oxide.

4. The process of claim 3 wherein said waste is a composition comprising sodium azide, sodium nitrate and iron oxide.

5. The process of claim 3 further including the step of recovering said water insoluble solids.

6. The process of claim 3 wherein the nitrate is recovered by evaporation of water therefrom.

7. The process of claim 1 wherein said alkaline aqueous slurry has a pH more than about 8.

8. The process of claim 1 wherein said waste is a gas generating material containing an alkali metal azide and a metal oxide.

9. The process of claim 8 wherein said alkali metal azide is sodium azide and said metal oxide is iron oxide or copper oxide.

10. The process of claim 8 wherein the waste contains a water soluble oxidant.

11. A process for treating a gas generating material waste which contains an azide having the formula XN₃, where X is an alkali metal, and a water insoluble metal oxide reactable with said azide, comprising the steps of:

preparing an aqueous slurry containing said waste and having a pH more than about 9;

treating said aqueous slurry with a gaseous stream containing oxygen and ozone for a time, and with an amount of ozone, effective to oxidize said azide to nitrogen and nitrate ions in solution; and

separating said metal oxide from said solution.