Demilitarization of high burn rate propellants containing ferrocene or its derivatives

Abstract

An effective method to recover the catalyst material, ferrocene or its deatives, from high burn rate propellants comprises the method which uses compressed gas in the form of a near critical liquid to extract, remove, and recover the specific catalyst material directly from rocket motors or from chunks of cut propellant. The method comprises introducing compressed carbon dioxide into a pressure vessel containing the propellant from which the catalyst material is to be recovered. The carbon dioxide as a near critical liquid (NCL) is circulated within the pressure vessel where extraction of ferrocene or its derivatives directly from the propellant takes place. The NCL with extractibles is transported to a warming and recovery zone where the extractibles are recovered after the carbon dioxide is volatilized and returned for recycling, compressing, and further extracting after being adjusted to a near critical liquid. Analytical data indicates that from 99.8% to 100% of ferrocence or its derivatives is readily recoverable from propellant which is undergoing demilitarization after it is determined to have burning rate, sensitivity, or other measureable changes to be out of system specification. After recovery of the high dollar value catalyst material, the propellant can be safely handled for removal using conventional water jet apparatus to cut and remove the propellant for reclamation of any of the propellant ingredients.

We claim: 
     
       1. A method for extracting, removing, and recovering ferrocene or its derivatives from a solid propellant composition comprised of ammonium perchlorate, aluminum, crosslinked hydrocarbon binder, and said ferrocene or its derivatives, said method comprising: i. introducing compressed carbon dioxide gas at a predetermined pressure and temperature which results in said compressed carbon dioxide being in a near critical liquid state into a pressure vessel containing cooled solid propellant composition having ferrocene or its deivatives as a dispersed ingredient that is extractible by said near critical liquid, said pressure vessel having an inlet means for introducing said near critical liquid and said pressure vessel having an outlet means having a plurality of perforations for discharging the near critical liquid and extractibles from said pressure vessel;   ii. providing an extraction time to achieve extraction of ferrocene or its derivatives from said propellant composition;   iii. providing an extended extraction time to achieve maximum extraction by circulating within said pressure vessel said near critical fluid containing ferrocene or its derivatives as extractibles;   iv. removing said near critical liquid containing said extractibles to a collection chamber;   v. effecting pressure change and temperature change of said near critical liquid containing said extractibles to achieve a phase change and subsequent evaporation of carbon dioxide to a gas to thereby achieve a separation of said extractibles;   vi recycling said carbon dioxide gas through a compressor for compressing to a compressed gas; and,   vii. recovering said extractibles which include ferrocene or its derivatives.   
     
     
       2. The method of claim 1 wherein said predetermined pressure of said compressed carbon dioxide is about 760 psig, and said propellant is about 31° C. 
     
     
       3. The method of claim 2 wherein 99.8% of ferrocene is recovered from said propellant composition, and wherein said pressure vessel is a rocket motor. 
     
     
       4. The method of claim 2 wherein said ferrocene derivative is 2,2-bis(ethylferrocenyl)propane, said pressure vessel is a rocket motor, and wherein 100% of said 2,2-bis(ethylferrocenyl)propane is recovered from said propellant composition.