(19) TZZ ¥Z _T (11) EP 2 305 624 A1 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.: 06.04.2011 Bulletin 2011/14 C06B 21/00 (2006.01) C06B 23/00 (2006.01) C06B 45/10 (2006.01) F42B 33/06 (2006.01) (2007.01) (2007.01) (21) Application number: 09382190.8 A62D 3/02 A62D 3/30 (22) Date of filing: 01.10.2009 (84) Designated Contracting States: (72) Inventors: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR • Botija Gonzalez, José Manuel HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL E-48960, Galdácano (Vizcaya) (ES) PT RO SE SI SK SM TR • Beitia Gomez de Segura, Fernando María Designated Extension States: E-28042, Madrid (ES) AL BA RS (74) Representative: ABG Patentes, S.L. (71) Applicant: Maxamcorp Holding, S.L. Avenida de Burgos 16D 28042 Madrid (ES) Edificio Euromor 28036 Madrid (ES) (54) Self-degradable explosive formulations (57) The present invention relates to self-degradable, shaped explosive formulations, comprising a molecular ex- plosive and a water-swellable polymer. EP 2 305 624 A1 Printed by Jouve, 75001 PARIS (FR) EP 2 305 624 A1 Description Field of the Invention 5 [0001] The present invention generally relates to the remediation of explosives which have not detonated; particularly to the degradation of shaped explosive formulations comprising a molecular explosive by means of physical-mechanical decomposition thereof and, if desired, converting the molecular explosive into a safe or environmentally acceptable compound. 10 Background of the Invention [0002] In the production of explosive formulations for seismic surveys as well as in the production of military devices (e.g., anti-tank mines, anti-personnel mines, bombs, etc.) and in initiators, compounds based on nitro groups (nitrode- rivatives), nitrate esters (nitroesters) and nitramines are commonly used. Representative examples of said compounds 15 include nitroglycerine, nitroglycol, 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), octogen or cyclote- tramethylene tetranitramine (HMX), cyclonite or cyclo-1,3,5-cyclotrimethylene-2,4,6-trinitramine (RDX), etc. These com- pounds can be used alone or combined with one another or with other non-explosive materials, depending on the applications for which they are intended. By way of example, the use of TNT/PETN (Pentolite) and TNT/RDX (Composition B) mixtures is common in seismic surveys. 20 [0003] Seismic surveys, for example, those conducted for gas and petroleum exploration, are commonly carried out under complicated conditions and, occasionally, the explosive charges used do not detonate due, for example, to failures in the initiation system. As a result, undetonated explosive charges can remain buried in the soil or in the subsoil but containing potentially explosive compounds that can be accidentally detonated with the resulting risk for people and animals. Furthermore, due to their chemical composition, said compounds (nitroderivatives, nitroesters and nitramines) 25 can generate a serious environmental problem. [0004] Explosive formulations intended for seismic surveys have some particular characteristics since, on one hand, they must maintain their explosive characteristics for at least 6 months from being placed in the subsoil, and, on the other hand, if they do not detonate, their explosive characteristics must disappear at the end of a determined time period so that they cannot be subsequently initiated or detonated due to an external stimulus, thus reducing the risk for the 30 population of an accidental detonation. Nevertheless, given that most used explosive components, such as nitroderiv- atives, nitroesters and nitramines, have a half-life of more than 20 years, the latent risk for people is very high. [0005] The removal of explosives which have not detonated is a very complicated and dangerous job and, occasionally, virtually impossible. To that end, several methods and systems for the degradation of undetonated explosive compositions (remediation) have been developed. 35 [0006] Some of said methods for the degradation of undetonated explosive compositions comprise the use of micro- organisms capable of decomposing said explosive compounds (bioremediation) which are incorporated in the explosive formulation for their manufacture (see, for example, US patent 7,240,618). However, the use of microorganisms gives rise to a number of both economic and technological drawbacks since the explosive formulations generally used in seismic surveys are prepared melting the molecular explosive at a high temperature (close to 100˚C) which can cause 40 the decomposition of all or a large part of the microorganisms, their capacity to degrade the explosive compounds thus disappearing. In addition, the microorganisms need available nutrients to be able to develop their activity; the supply of such nutrients complicates the development and production of such explosive formulations. [0007] Other methods for the degradation of undetonated explosive compositions are based on the use of enzymes capable of degrading nitroderivatives or nitroesters. In this sense, the capacity of several redox enzymes, such as 45 ferredoxin NADP oxidoreductase, glutathione reductase, xanthine oxidase and oxyrase, to convert TNT into 4-hydrox- ylamino-2,6-dinitrotoluene (4-HADNT), as well as the capacity of the PETN reductase to degrade PETN (WO 97/03201) and TNT (WO 99/32636), are known. However, the use of enzymes is very delicate and presents the drawback that the enzymes can be inactivated if the conditions of the environment alter their shaping or secondary structure, they thereby lose their capacity to degrade said compounds. 50 [0008] Methods for the degradation of undetonated explosive compositions based on the use of chemical reagents for the degradation of said explosive compounds (chemical remediation), for example, the use of sodium chlorite to degrade RDX and HMX, have also been described; nevertheless, said methods require the dissolution of reagents and explosives to be degraded and, in addition, when the chemical reagent selected is very reactive with the explosive compounds (e.g., a chlorite), a composition that is unsafe both in its manufacture and in its use could be generated. 55 [0009] Although there are several methods and systems for reducing the risk of detonation of undetonated explosive charges, there is still a need to develop alternative methods and systems with respect to those existing which overcome all or some of the previously mentioned drawbacks. Advantageously, said methods and systems must enable, in addition to the decomposition of the undetonated explosive charge, the conversion of the explosive compounds into inert com- 2 EP 2 305 624 A1 pounds and/or their degradation for the purpose of reducing or eliminating the environmental pollution caused by said compounds. Brief Description of the Drawings 5 [0010] Figure 1 is a schematic depiction of an explosive device provided by this invention comprising a shell (2) provided with side holes (3) for housing the self-degradable formulation of the invention (1) and in which an initiation system 10 or detonator (4) is housed. Figure 2 is a schematic depiction of a variant of the explosive device provided by this invention shown in Figure 1 in which the holes (3) of the shell (2) housing the self-degradable formulation of the invention (1) are sealed with a water-porous or water-soluble material (3’). Figure 3 is a graph showing the degradation rate of TNT in aqueous solution with iron (Fe0) powder in different 15 amounts. Figure 4 is a graph showing the degradation rate of PETN in aqueous solution with iron (Fe0) powder in different amounts and at different pH values. Detailed Description of the Invention 20 [0011] In one aspect, the invention provides a self-degradable, shaped explosive formulation, substantially free of water-soluble oxidizing salts, hereinafter self-degradable formulation of the invention, comprising: - at least one molecular explosive, and 25 - between 0.2% and 1% by weight with respect to the total weight of the explosive formulation of a water-swellable polymer. [0012] As it is used herein, the expression "substantially free of water-soluble oxidizing salts" means that the self- degradable formulation of the invention lacks, or contains an amount equal to or less than 1% by weight with respect 30 to the total weight of the explosive formulation of the invention, of one or more completely or partially water-soluble oxidizing salts used in the production of explosive formulations, for example, ammonium nitrates, chlorates and per- chlorates, or of alkaline or alkaline-earth metals, and mixtures thereof. In a particular embodiment, the self-degradable formulation of the invention contains an amount equal to or less than 0.5% by weight with respect to the total weight of the explosive formulation of the invention, of said oxidizing salts; preferably, the self-degradable formulation of the 35 invention lacks said completely or partially water-soluble oxidizing salts used in the production of explosive formulations. [0013] The term "shaped" in the sense used in the present description means that the self-degradable formulation of the invention has a determined spatial or three-dimensional configuration, for example, cylindrical, etc., in which its components are bound by cohesive and/or adhesive forces. [0014] Likewise, as it is used herein, the term "self-degradable" applied to an explosive formulation means that said 40 explosive formulation is converted into a non-explosive formulation or into a formulation