EP0858816A1 - Process for treating explosives - Google Patents

Abstract

A process for the decomposition of explosives into water-soluble products is offered, which can be completely disposed of thermally and / or biochemically, which by adding polar, aliphatic, non-saponifiable compounds to a strongly basic, preferably aqueous reaction medium and under controlled temperature control by metered addition explosives only need very short reaction times.

Description

The present invention relates to a method for the safe chemical degradation of Explosives on a technical scale to water-soluble reaction products, either are thermally, biochemically or combined biochemically and thermally disposable.

In this context, explosive substances can be detonated Fuels and explosives from the class of nitric acid esters, e.g. Nitrocellulose, Nitramines, e.g. Hexogen, nitro compounds, e.g. Trinitrotoluene, and batch understood of these explosives, which are carried out entirely by the remaining parts of the ammunition to be disposed of have been separated.

There is always a need to dispose of explosives when there is no storage capacity there is more for outdated ammunition, or if the chemical stability of less resistant explosives, e.g. Nitrocellulose, in aged ammunition Represents security risk.

Known and frequently used methods for the disposal of explosives are the Burning open and blowing up. For safety and / or ecological reasons these procedures are no longer allowed or only, in the case of compelling reasons, with Temporary exceptional permits can be carried out.

When burning openly, the explosives are burned openly in loose, low fillings, sometimes also in mixtures with desensitizing liquid or solid fuels, such as oils, solvents or sawdust, on fireplaces set up for this purpose. Toxic organic residues can get into the groundwater. In addition, the gaseous reaction products have an intolerably high NO _x concentration in today's opinion. There is a risk of detonation if too large amounts of explosive are used in an overfill. In addition, when using a fire place at short intervals, the embers hidden in the solid residues can lead to premature ignition when refilling new material. Serious accidents resulting from such occurrences are known.

When detonating, the detonation, which takes place under high pressure and temperature, leads to gaseous reaction products with tolerably small proportions of toxic reaction products such as carbon monoxide and NO _x. However, a disadvantage is the great effort to cordon off the blasting site, the noise pollution and the risk of accidents.

The most frequently used explosive disposal method in Western countries at the moment is closed combustion. This term is understood to mean the burning of explosives in stoves specially developed for this purpose, which are equipped with a denitrification device for removing NO _x . The plants meet the current ecological requirements. If work is to be carried out economically, the high investment costs and the risk of detonation, which cannot be completely eliminated, are to be assessed as disadvantageous.

Further disposal methods for explosives, which are known according to their principle and in some cases also proposed but have not yet been used on an industrial scale, are multi-stage. In the first stage, the explosives are first chemically broken down into non-toxic, water-soluble products
The other disposal stages include the options for the biochemical degradation of these products or their safe combustion in a waste incineration plant. The biochemical degradation can take place directly through the use of the neutralized, aqueous solution as liquid fertilizer or indirectly through the formation of sewage sludge, which can also be used as a fertilizer but is also combustible. To convert it into sewage sludge, the aqueous solution can be fed to a sewage treatment plant with sufficient capacity. From an economic point of view, however, direct use as liquid fertilizer makes sense because it is a valuable product that can be produced with the simplest of means.

In "ENCYCLOPEDIA OF EXPLOSIVS AND RELATED ITEMS", Picatinny Arsenal, Dover, New Jersey, USA, the volumes listed below contain information on the disposal of explosives using a multi-stage process: PATR 2700, 1966, Vol 3 (D 30) describes a process for the chemical degradation of nitrocellulose, in which 100 lbs of the explosive are chemically degraded by portionwise addition to a 70 ° C. stirred solution of 50 lbs NaOH and 460 lbs water. The same chapter also lists a laboratory procedure in which chemical degradation is carried out with a 15% aqueous Na ₂ S solution in a water bath. In chapter C 26 it is recommended to use the inorganic nitrates obtained from water-soluble explosives, such as ammonals and black powders, by water extraction, i.e. products that also result from the chemical degradation of the water-insoluble explosives, as fertilizer.

In "HAZARDS OF CHEMICAL ROCKETS AND PROPELLANTS", Volume 1, CPIA PUBLICATION 394, September 1984, the disposal options are also treated Explosive waste due to biodegradation and / or incineration.

In "Chemistry and Technology of Explosives", Volume 11, Leipzig 1963, T. Urbanski for nitrocellulose that has been treated with sodium or potassium hydroxide solution, the following reaction products specified: ammonia, nitrogen, carbon dioxide, alkali nitrate and nitrite, alkali salts of formic, oxalic, malonic, hydroxy and non-identifiable keto and aldehyde acids and sugar. As hydroxy acids e.g. Malic acid and dihydroxybutyric acid specified. According to this information, the resulting water-soluble solids are due to their chemical structure using the known methods both biochemically and can be disposed of thermally without any problems, provided that the excess is used for chemical degradation Bases with inorganic or organic acids, e.g. Phosphorus, sulfur, Acetic or formic acid can be neutralized.

Finally, US Pat. No. 4,231,822 protects a mining process by reducing it with expensive ones organic compounds that require uneconomically long reaction times.

The described processes for the chemical degradation of explosives, in particular of nitrocellulose, are either intended for small quantities or have the character of Principle tests for basic clarifications, in which the reaction time does not matter plays. They are unsuitable for industrial use for the following reasons: The explosives are usually as coarse crystals or in the case of polymeric compounds Granules before, the described degradation reactions with bases and / or reducing agents run strongly exothermic. When the explosives are added to the aqueous solution of the reactive substances is at the specified low temperatures in the range of 70 ° C Mass sales small because of the small particle surface. That is why initially only occurs weak temperature rise. When adding too large quantities of explosives this becomes exponential in a short time for large batches due to a heat build-up and thus lead to a dangerous rise in temperature, which is no longer possible even with strong cooling is controllable. Another disadvantage of the process is that the reaction occurs after sales of half of the total amount of explosives decrease so much that the temperature must be increased continuously by heating. This effect makes safe process control difficult and inevitably extends the response time.

DE 40 36 787 A1 claims a method in which the hydrolytic cleavage of explosives is carried out very generally by lye in the presence of solubilizers. Among the solubilizers, alcohols are also mentioned without being recognized as having any further advantageous influence on the reaction.

The object of the invention is therefore a safe, fast and therefore specify economic process for the removal of explosives, which is for industrial Suitable for use with thermal and / or biological disposal the degradation products can be coupled.

This object is achieved with the method for breaking down explosives into water-soluble, biochemically or thermally disposable products with the characterizing features of claim 1 .

• dosiert einem flüssigen Reaktionsmedium zugeführt werden, das aus der Lösung von mindestens einem anorganischen Reduktionsmittel und/oder mindestens einer starken Base mit einem Zusatz von 10 bis 30 Gew.%, bevorzugt 15 bis 25 Gew.%, eines polaren, aliphatischen, nicht verseifbaren
  
  Lösungsmittels
  
  , bezogen auf die Menge der wässrigen Lösung, besteht,
• darin unter Durchmischung und einer Temperaturführung, die das Reaktionsmedium bevorzugt am Sieden hält, wobei das Lösungsmittel bei konstanter Temperatur unter Rückflusskühlung siedet, in exothermem Abbau in lösliche Verbindungen umgesetzt werden.,
• worauf das Reaktionsmedium wahlweise durch mindestens eine anorganische Säure neutralisiert
• und das Neutralisationsgut mindestens teilweise isoliert wird,
• Nachfolgend kann die vollständige Entsorgung auf thermischem oder biochemischem Wege erfolgen.

The object is achieved in particular by a method in which solid explosives

• be metered into a liquid reaction medium which, from the solution of at least one inorganic reducing agent and / or at least one strong base with the addition of 10 to 30% by weight, preferably 15 to 25% by weight, of a polar, aliphatic, unsaponifiable
  
  Solvent
  
  , based on the amount of the aqueous solution,
• therein with thorough mixing and temperature control, which preferably keeps the reaction medium at the boil, the solvent boiling at constant temperature with reflux cooling, in exothermic decomposition into soluble compounds.
• whereupon the reaction medium is optionally neutralized by at least one inorganic acid
• and the neutralization material is at least partially isolated,
• The complete disposal can then be carried out by thermal or biochemical means.

The reaction medium is preferably aqueous and has a pH of about 14 during the entire degradation reaction.
The components bases, reducing agent, water and solvent preferably form a reactive dispersion in the stirred state, in which the solvent content is advantageously kept constant until the end of the decomposition reactions.
The reaction and temperature control is made possible by the continuously or discontinuously metered amount of explosive in such a way that the reaction enthalpy of the explosive corresponds to the enthalpy of evaporation of the boiling solvent, or its azeotrope, which is returned to the process by means of reflux cooling. Intensive mixing, preferably by stirring, is advantageous.
Constant temperature control is particularly advantageous for the degradation reaction, since the reaction is highly exothermic. In addition, the cooling effect of the boiling solvent is, at least temporarily, advantageously supported by external cooling of the reaction medium.

The term solvent is understood to mean organic compounds which are polar, aliphatic and non-saponifiable and which preferably boil significantly lower than the aqueous portion of the reactive medium, in contrast to the teaching of DE 40 36 787 A1 having no solvent effect on the explosives is required.
Preferred solvent are methanol, ethanol, propanol and isopropanol, as well as ketones such as acetone, methyl ethyl ketone and diethyl ketone.

Their effect lies, in addition to the aforementioned regulating influence on the temperature control in the Reaction medium, in a rapid acceleration of the reaction rate of degradation of the explosives, which can increase to 4- to 6-fold using the example of nitrocellulose as well as and in the very advantageous damping of the foam development in the preferably aqueous concentrated reaction medium.

The aqueous bases of NaOH and KOH are preferably used as strong bases, the effective concentration of which has to be determined according to economic considerations. Sodium hydroxide solution of at least 20% by weight and potassium hydroxide solution of at least 27% by weight are particularly preferred. The upper concentration limit is determined by the viscosity of the aqueous solutions and the solubility parameters of the added solvents and is around 40% by weight.
For the already mentioned example nitrocellulose, an empirical value of 0.75 kg NaOH per kg nitrocellulose has proven to be advantageous for the complete breakdown.

The concentration of the inorganic reducing agents which are optionally used, which are preferably NaHS and Na ₂ S, is between 5 and 30% by weight, depending on the base concentration.

The neutralization of the strongly alkaline reaction medium, which is preferred in the stirred state is present as a dispersion consisting of water, degradation products, excess bases and reducing agents and solvents, these components being dissolved Form in different proportions on the dispersion phases is advantageous matched to the disposal of the fully dismantled explosives. For solutions, that are to be biodegraded in wastewater treatment plants is usually not Neutralization required.

For use as fertilizer it is preferred to neutralize with phosphoric acid.

In addition, nitric acid and sulfuric acid are preferred. Of course, depending on the use of the so-called Neutralization goods , other inorganic or organic acids can also be used.

As a further step in the method according to the invention, an at least partial isolation of the Neutralization goods advantageous. Particularly advantageous is the at least partial distillation of the solvent, which can be reused in this way, while it even interferes, for example, when used as a fertilizer or in thermal disposal by burning.

For biological disposal with further use of the Neutralization goods As a fertilizer, it is advantageous to add or supplement selected ones
Plant nutrients to meet the corresponding requirement profile, which is defined specifically for the content of nitrogen, phosphorus and potassium as NPK value.

• das Reaktionsmedium durch die Lösungswärme der Alkalihydroxyde weitgehend auf die Reaktionstemperatur aufgeheizt wird,
• der Abbau der Explosivstoffe ohne Zufuhr von Fremdenergie bei der Siedetemperatur des Lösungsmittels oder dessen Azeotrops, abläuft,
• die Abbaureaktion durch das am Rückfluss siedende Lösungsmittel und die dadurch konstante Reaktionstemperatur, die bevorzugt deutlich unter dem Siedepunkt des Wassers liegt, ohne weitere Sicherheitsvorkehrungen unfallsicher gestaltet werden kann,
• durch Verwendung kostengünstiger Lösungsmittel der Zeitbedarf für die Umsetzung drastisch gesenkt wird,
• durch die Verwendung der Abbauprodukte als Düngemittel Anteile der Kosten rückgeführt werden können.

Die ganz besonderen Vorteile liegen im gefahrlosen und umweltfreundlichen Ablauf des Verfahrens und seinen nicht-toxischen Endprodukten.The method according to the invention is therefore particularly advantageous and inexpensive because

• the reaction medium is largely heated to the reaction temperature by the heat of solution of the alkali metal hydroxides,
• the decomposition of the explosives takes place without the supply of external energy at the boiling point of the solvent or its azeotrope,
• the degradation reaction due to the solvent boiling at the reflux and the constant reaction temperature thereby, which is preferably clearly below the boiling point of the water, can be made accident-proof without further safety precautions,
• the time required for the implementation is drastically reduced by using inexpensive solvents,
• By using the degradation products as fertilizers, parts of the costs can be reduced.

The very special advantages are the safe and environmentally friendly process and its non-toxic end products.

The advantages of the invention are explained in more detail in the following two examples:

Example 1 (comparative example )

Method not according to the invention, without adding a so-called Solvent , for comparison.

In a wall-heated reactor, 15.6 kg of NaOH solution with a concentration were added of 35%, set to an isothermal temperature of 90 ± 2 ° C, in the course of 195 minutes 7.30 kg of "nitrocellulose" with stirring in increasing amounts fed. Under this condition, the temperature of the reactor contents moved in one Range from 88 to 108 ° C with a standard deviation of 5 ° C around an average from 101 ° C. After the reaction has subsided, recognizable by the drop in temperature after the At the end of the addition, the temperature of the heating circuit was raised from 97 to 103 ° C. After Almost all remaining explosive particles had been converted within 150 minutes. While During this phase the temperature of the kettle contents dropped from 100 to 97 ° C.

• "Nitrocellulose": Treibladungspulver für Artilleriemunition in der Form von Streifen mit den Abmessung 495x11x1 mm, auf eine Länge von 60 mm gebrochen.
• Eingesetzte spezifische Menge NaOH fest: 0.75 kg/kg "Nitrocellulose".
• Aspekt und Eigenschaften der Reaktionslösung: Niederviskos, dunkel, pH 14.
• Umsatz, ermittelt durch Dekantieren der Reaktionslösung und Isolieren der zurückgebliebenen Partikel: 99.8 %.
• Reaktionsdauer: 5.8 Stunden.

The most important process data are:

• "Nitrocellulose": propellant powder for artillery ammunition in the form of strips with the dimensions 495x11x1 mm, broken to a length of 60 mm.
• Specific amount of NaOH used: 0.75 kg / kg "nitrocellulose".
• Aspect and properties of the reaction solution: low viscosity, dark, pH 14.
• Turnover, determined by decanting the reaction solution and isolating the remaining particles: 99.8%.
• Response time: 5.8 hours.

Example 2 (Method according to the invention)

• "Nitrocellulose": Treibladungspulver für Artilleriemunition in der Form von Streifen mit den Abmessungen 495x11x1 mm, auf eine Länge von 20 mm gebrochen.
• Eingesetzte spezifischen Menge NaOH fest: 0.75 kg/kg "Nitrocellulose".
• Aspekt und Eigenschaften des Reaktionsmediums: Niederviskos, dunkel, pH 14.
• Umsatz, ermittelt durch Dekantieren der Reaktionslösung und Isolieren der zurückgebliebenen Partikel: > 99.9 %.
• Reaktionsdauer: 0.90 Stunden.

174 g of water and 37.4 g of ethanol were placed in a 500 cm ³ sulphonation flask with a reflux condenser. After the addition of 74.7 g of NaOH solid within 5 minutes with stirring, the temperature of the solution rose to the maximum value of 71 ° C. as a result of the enthalpy of solution. At this temperature the portionwise addition of 100 g of "nitrocellulose" began. Boiling occurred after 10 minutes at a temperature of the reaction medium of 77 ° C. The total amount of "nitrocellulose" was added with constant boiling of the reaction medium within 34 minutes. The maximum temperature of 80 ° C was reached after 35 minutes. After a total of 54 minutes, the temperature dropped to 70 ° C without external cooling.
The most important process data are:

• "Nitrocellulose": propellant powder for artillery ammunition in the form of strips with the dimensions 495x11x1 mm, broken to a length of 20 mm.
• Specific amount of NaOH used: 0.75 kg / kg "nitrocellulose".
• Aspect and properties of the reaction medium: low viscosity, dark, pH 14.
• Turnover, determined by decanting the reaction solution and isolating the remaining particles:> 99.9%.
• Response time: 0.90 hours.

Example 3 (Method according to the invention)

• Nitrocellulose : Treibladungspulver für Mittelkalibermunition in Form zylindrischer Granulate mit einer mittleren Masse von 0.063g/Partikel.
• Eingesetzte spezifische Menge NaOH fest: 0.75 kg/kg Nitrocellulose .
• Aspekt und Eigenschaften des Reaktionsmediums: Niederviskos, dunkel, pH 14, Phasentrennung.
• Umsatz, ermittelt durch Dekantieren des Reaktionsmediums und Isolieren der zurückgebliebenen Partikel: 99,1%.
• Reaktionsdauer: 1.o Stunden.

In the same experimental set-up as in Example 2, 37.4 g of 1-propanol were introduced instead of ethanol. After adding 74.7 g of NaOH solid within 4 minutes with stirring, the temperature of the solution rose to a maximum of 75 ° C. At this temperature the portionwise addition of the Nitrocellulose . Strong boiling occurred after 5 minutes at a temperature of 88.5 ° C. The total amount of 100g Nitrocellulose was added with constant boiling of the reaction medium within 33 minutes. The maximum temperature of the degradation reaction remains at about 88 ° C. After a total of 60 minutes, the temperature dropped to 70 ° C. without external cooling.
The most important test data are:

• Nitrocellulose : Propellant powder for medium-caliber ammunition in the form of cylindrical granules with an average mass of 0.063g / particle.
• Specific amount of NaOH used: 0.75 kg / kg Nitrocellulose .
• Aspect and properties of the reaction medium: low viscosity, dark, pH 14, phase separation.
• Sales, determined by decanting the reaction medium and isolating the remaining particles: 99.1%.
• Response time: 1.o hours.

Example 4 (Method according to the invention)

• Nitrocellulose : Treibladungspulver für Mittelkalibermunition in der Form zylindrischer Granulate mit einer mittleren Masse von 0.063g/Partikel.
• Eingesetzte spezifische Menge NaOH fest: 0.75 kg/kg Nitrocellulose .
• Aspekt und Eigenschaften des Reaktionsmediums: Niederviskos, dunkel, pH 14, Phasentrennung.
• Umsatz: ermittelt durch Dekantieren und Isolieren der zurückgebliebenen Partikel:
• 98,7%.
• Reaktionsdauer: 1.2 Stunden.

In the same experimental set-up as in Example 2, 37.4 g of acetone were introduced instead of ethanol. After adding 74.7 g of NaOH solid within 10 minutes with stirring, the temperature of the solution rose to the maximum value of 58 ° C. with strong boiling. After the temperature dropped to 56 ° C, the portionwise addition of Nitrocellulose .
After 6 minutes boiling occurred again at 57 ° C. The addition of the total amount of 100g Nitrocellulose was carried out with constant stirring within 27 minutes. The maximum temperature of the degradation reaction of 61 ° C was reached after 43 minutes and after a total of 71 minutes the temperature dropped to 53 ° C without external cooling.
The most important process data are:

• Nitrocellulose : Propellant powder for medium-caliber ammunition in the form of cylindrical granules with an average mass of 0.063g / particle.
• Specific amount of NaOH used: 0.75 kg / kg Nitrocellulose .
• Aspect and properties of the reaction medium: low viscosity, dark, pH 14, phase separation.
• Turnover: determined by decanting and isolating the remaining particles:
• 98.7%.
• Response time: 1.2 hours.

Claims (12)

Process for breaking down explosives into water-soluble , biochemically or thermally disposable products, with the steps: a. Adding a solid explosive to a liquid reaction medium which contains at least one inorganic reducing agent and / or at least one strong base, b. exothermic decomposition of the explosive with mixing and temperature control to soluble compounds, c. optionally neutralizing the reaction medium by adding at least one inorganic acid, d. at least partially isolate the

Neutralization goods

and e. Disposal of the Neutralization goods ,
characterized in that
the reaction medium is aqueous and additionally contains 10 to 30% by weight of a polar, aliphatic, non-saponifiable solvent, the enthalpy of vaporization of which is kept in equilibrium with the enthalpy of reaction of the explosive by the metering rate at which the explosive is added to the reaction medium, thereby contributing to the degradation reaction constant temperature is carried out. Method according to claim 1 ,
characterized in that
the degradation is carried out in the boiling reaction medium under reflux of the solvent or its azeotrope. The method of claim 1 or 2 ,
characterized in that
the reaction medium has a pH of about 14 during degradation. Method according to one of the preceding claims,
characterized in that
the solvent is a compound boiling lower than the aqueous portion of the reaction medium, selected from the group consisting of methanol, ethanol, propanol, i-propanol, acetone, methyl ethyl ketone and diethyl ketone. Method according to one of the preceding claims,
characterized in that
the strong base is selected from the group NaOH and KOH. Method according to one of the preceding claims,
characterized in that
the reducing agent is selected from the group Na ₂ S and NaHS. Method according to one of the preceding claims,
characterized in that
the acids are selected from the group consisting of sulfuric acid, phosphoric acid and nitric acid. Method according to one of the preceding claims,
characterized in that
for temperature control, the reaction medium is cooled at least temporarily. Method according to one of the preceding claims,
characterized in that
the reaction medium is mixed by stirring. Method according to one of the preceding claims,
characterized in that
to at least partially isolate the neutralization material, the low-boiling solvent is at least partially distilled off. Method according to one of the preceding claims,
characterized in that
Disposal takes place thermally by incineration or biologically via clarification processes or as fertilizer. A method according to claim 11 ,
characterized in that
it is disposed of as fertilizer after the addition of supplementary plant nutrients.