US 3897237 A
A process for the disposal of pyrotechnic flares comprised essentially of magnesium, sodium nitrate and a binder. The flare is crushed and then soaked in a solvent which softens and dissolves the binder material. The dissolved binder and solvent is decanted and the remaining magnesium and sodium nitrate are washed in water which dissolves the sodium nitrate. The aqueous solution of sodium nitrate is removed and is useful as a fertilizer. The remaining magnesium is dried and screened and is reusable as an ingredient in a pyrotechnic device.
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Description (OCR text may contain errors)
States Musselman et a1.
[451 July29, 1975 1 PROCESS FOR DISPOSING OF PYROTECHNIC FLARES Inventors: Kenneth A. Musselman, Loogootee;
James E. Short, Jr., Switz City, both of Ind.
 Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.
 Filed: Aug. 2, 1974  Appl.No.: 494,131
US. Cl 71/1; 71/58 Int. C1. COSC 5/02 Field of Search 23/266; 149/61; 102/24;
References Cited UNITED STATES PATENTS 11/1935 Strathmeyer 71/58 X Griffith et al. 102/24 R Griffith et a]. 102/24 R Primary ExaminerFrank A. Spear, Jr. Assistant Examiner-Ferris H. Lander Attorney, Agent, or FirmR. S. Sciascia; Paul S. Collignon  ABSTRACT 5 Claims, 1 Drawing Figure PYROTECHNIC COMPOSITION CRUSH DISSOLVE METHYLENE CHLORIDE SOLUTION DECANT SOLVENT 8i BINDER WASH = ISOPROPYL ALCOHOL DECANT ALCOHOL a BINDER WASH -WATER DECANT FERTILIZER DRY 8i SCREEN MAGNESIUM PATENTEI] JUL 2 9 I975 PYROTECHNIC COMPOSITION CRUSH DISSOLVE CHLORIDE DECANT SOLVENT 8x BINDER WASH ISOPROPYL ALCOHOL DECANT ALCOHOL 8x BINDER WASH @WATER DECANT FERTILIZER DRY 8 SCREEN MAGNESIUM PROCESS-FOR DISPOSING OF PYROTECHNIC FLARES BACKGROUND OF HaINyENTI N The invention relates to a method fordisposing of pyrotechnic flares and more particularly to a nonpolluting method of disposing of flares comprised of magnesium, sodium nitrate'and a'binder and also for a method of disposing of waste materials which come from the manufacture of such flares.
It is necessary to dispose of waste pyrotechnic flare compositions as its storage is both costly and hazardous. Waste flare composition may either be bulk composition, left over from a production run or might be from defective illuminating flare candles. At one Naval Ammunition Depot, for example, over 900 pounds of pyrotechnic bulk production wastes were accumulated each day during a peak production period.
I-Ieretofore the main disposal method for such pyrotechnic waste was to burn the waste in an open buringpit in a sparsely populated area. In some cases, disposable of unserviceable items was accomplished by dumping at sea. Both methods, however, are undesirable because of pollution to either the air or water.
SUMMARY OF THE INVENTION The present invention relates to a process for disposing of pyrotechnic compositions comprised of magnesium, sodium nitrate and a binder which is either an unsaturated polyester or an epoxy. The material is first crushed and then placed in a solvent, such as a methylene chloride based stripper material, and allowed to soak until the binder becomes soft and dissolves. The solvent and dissolved binder are then decanted off and the remaining ingredients are washed in water which dissolves the sodium nitrate. The aqueous solution of sodium nitrate is removed and is useful as a fertilizer. The remaining magnesium is then dried and screened and is reusable as an ingredient in a pyrotechnic device.
It is therefore a general object of the present invention to provide a method for disposing of a flare composition which is safe and non-polluting of the environment.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING The FIGURE of the drawing is a block diagram showing the steps of a preferred method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT In the disposal method of the present invention, the three ingredients of the flare are first separated and then disposed of in an ecologically permissible and useful manner. By way of example, a flare composition might be comprised, by weight, of about 58 percent of magnesium, about 38 percent of sodium nitrate and about 4 percent of a binder. The binder is either an epoxy or an unsaturated polyester.
Prior to separation of the three basic ingredients of the composition, the pyrotechnic composition is first crushed by suitable means, such as by a hydraulically operated crushing blade. When waste production materounding the candle composition is removed. After crushing, the candle pieces or the waste composition pieces are fed into a mixing tank and allowed to soak in a solvent solutionfor about 30 minutes. Preferably the pieces and solvent solution are stirred at about 500-600 rpm, using an air operated mixing motor. One solvent used successfully is a methylene chloride based stripper which is comprised,by weight, of about 25 percent methylene chloride, about 25 percent isopropyl alcohol and about 50 percent water. The reaction of this solvent with the binder causes the hardened binder to soften and separate from the magnesium and sodium nitrate. The solvent and dissolved binder are decantedoff and that portion of the binder that is not removed by the solvent is washed away by isopropyl alcohol.
The remaining ingredients are next given a water wash which dissolves sodium nitrate. The ingredients are washed for about 15 minutes and the solution is agitated at about 500-600 rpm. The aqueous solution of sodium nitrate is filtered and the aqueous solution is useful as a fertilizer. Water does not vigorously attack the magnesium. In actuality, magnesium decomposes water slowly because its hydroxide, which results from the reaction:
is insoluble and once the hydroxide has been formed on the surface, the hydroxide hinders any further attack on the magnesium. After the aqueous solution of sodium nitrate is removed, the remaining ingredient, magnesium is dried by placing in open pans and heated at about l40 F., in a vented oven. The dried magnesium is screened through a No. 20 (841 micron) sieve and the magnesium passing through the sieve is useful as a fuel in pyrotechnic devices. In tests conducted at the Naval Ammunition Depot, Crane, Indiana, laboratory analysis of the screened magnesium indicated that the screened product was between 91 and 96 percent magnesium, and the product was successfully used in the manufacture of flares.
It can thus be seen that the present invention provides a disposal method for a pyrotechnic composition which does not pollute the environment. Further, that a portion of the ingredients of a pyrotechnic composition are recycled to provide useful end products.
Obviously may modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
I We claim:
1. A process for isolating and disposing of the chemical ingredients in illuminating flares comprised of magnesium, sodium nitrate, and a binder, said process comprising,
first crushing said chemical ingredients,
then dissolving said binder in a solvent,
then decanting to remove said solvent and the dissolved binder,
then washing the remaining chemical ingredients in water to dissolve sodium nitrate,
then decanting the aqueous solution of sodium nitrate for use as a fertilizer, and
then drying and screening the remaining ingredients for use as a fuel in pyrotechnic devices.
2. A process for isolating and disposing of the chemical ingredients in illuminating flares as set forth in claim 1 wherein said solvent is an aqueous solution of 5 methylene chloride comprised, by weight, of about 25 percent of methylene chloride, about 25 percent of isopropyl alcohol and about 50 percent of water.
3. A process for isolating and disposing of the chemical ingredients in illuminating flares as set forth in claim 1 wherein the step of first decanting to remove said solvent and the dissolved binder is followed by utes.