Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
  • A62D3/10—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by subjecting to electric or wave energy or particle or ionizing radiation
  • A62D3/11—Electrochemical processes, e.g. electrodialysis
  • A62D3/115—Electrolytic degradation or conversion
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
  • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
  • C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
  • C02F1/4672—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
  • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
  • C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
  • C02F1/4676—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electroreduction
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/06—Explosives, propellants or pyrotechnics, e.g. rocket fuel or napalm
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/40—Inorganic substances
  • A62D2101/45—Inorganic substances containing nitrogen or phosphorus
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
  • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
  • C02F1/46104—Devices therefor; Their operating or servicing
  • C02F1/46109—Electrodes
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
  • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
  • C02F1/46104—Devices therefor; Their operating or servicing
  • C02F1/46109—Electrodes
  • C02F2001/46119—Cleaning the electrodes
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
  • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
  • C02F1/46104—Devices therefor; Their operating or servicing
  • C02F1/46109—Electrodes
  • C02F2001/46133—Electrodes characterised by the material
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
  • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
  • C02F1/46104—Devices therefor; Their operating or servicing
  • C02F1/46109—Electrodes
  • C02F2001/46152—Electrodes characterised by the shape or form
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/003—Explosive compounds, e.g. TNT
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/30—Organic compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/30—Organic compounds
  • C02F2101/38—Organic compounds containing nitrogen
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2201/00—Apparatus for treatment of water, waste water or sewage
  • C02F2201/46—Apparatus for electrochemical processes
  • C02F2201/461—Electrolysis apparatus
  • C02F2201/46105—Details relating to the electrolytic devices
  • C02F2201/4612—Controlling or monitoring
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2201/00—Apparatus for treatment of water, waste water or sewage
  • C02F2201/46—Apparatus for electrochemical processes
  • C02F2201/461—Electrolysis apparatus
  • C02F2201/46105—Details relating to the electrolytic devices
  • C02F2201/46155—Heating or cooling

Definitions

• compositions of the type described above can be effectively desensitized, and thus rendered much less susceptible to inadvertent initiation, in a nonhazardous and controlled manner by electrolysis.
• the composition is placed in contact with two electrodes and an electric current is passed from one to the other through the composition.
• One or more of the active components in the compositions undergoes an electrolytic conversion in an oxidation or reduction reaction (or both) at the appropriate electrode, thereby lowering the susceptibility of the composition to initiation.
• the invention is most conveniently performed by macerating the solid material and combining it with a liquid to form a slu ⁇ y prior to placing it in contact with the electrodes.
• the liquid will be one which will improve the transport of ions through the composition in response to the electric current, and preferably one which will dissolve one or more of the components of the composition to produce a dissolved electrolyte.
• the efficiency of the process will generally increase as the contact area between the solid and the liquid increases, and thus, higher degrees of maceration will generally result in improved efficiencies.
• the composition is placed in the electrolysis cell closer to one of the two electrodes than to the other, and preferably in contact with the closer electrode.
• the electrodes are then energized through a polarity switch which enables one to reverse the polarity.
• the electrode which is closer to the solid composition ie., the working electrode
• the electrode which is closer to the solid composition is first energized as an anode, thereby causing the binder to oxidize.
• This oxidation and resulting decomposition of the binder cause the composition to swell, thereby improving access of the ions produced by the electric current to the other components of the composition.
• the polarity is then either maintained or switched, depending on the remaining materials to be decomposed and the type of decomposition reaction required.
• the working electrode is switched to a negative polarity (cathode), whereas for oxidation reactions, the working electrode is held at a positive polarity (anode).
• a negative polarity is applied to the working electrode.
• FIG. 1 is a side view of a desensitizing processor which can be used in performing the process of the present invention.
• FIG. 2 is a block diagram of a system for driving, controlling and monitoring the processor of FIG. 1.
• FIG. 3 is a perspective view of a cell which may be used in the practice of the invention and is of a different configuration from that of FIG. 1.
• FIG. 4 is a diagram showing the cell of FIG. 3 in combination with electrical and temperature control systems.
• FIG. 5 is a diagram showing a third type of cell in which the present invention may be practiced.
• FIG. 6 is a plot of nitroglycerin content vs. time in a propellant composition undergoing desensitization in accordance with the invention.
• the present invention is applicable to a wide range of compositions of the type described above, including various formulations of propellants and explosives.
• Examples are single-base propellants, double-base propellants, cast double-base propellants, crosslinked propellants, single-component and multi-component explosives and plastic-bonded explosives.
• These compositions typically include explosive components, oxidants, fuels, and binders, the latter including both energetic and nonenergetic substances, including fuel-rich and/or oxidizer-rich binders, and other additives such as plasticizers, bonding agents, extenders, catalysts, stabilizers, lubricants and other types of modifiers, fillers and functional substances.
• Examples of specific energetic components are ammonium nitrate (AN), ammonium perchlorate (AP), ammonium picrate, 2,4-diamino-l,3,5-trinitrobenzene (DATB), diazodinitrophenol (DDNP), diethylnitramine dinitrate (DINA), ethylenedinitramine (EDNA), ethylene glycol dinitrate (EGDN), cyclotetramethylene tetranitramine (HMX), lead azide, lead styphnate, mannitol hexanitrate (MN), mercury fulminate, nitrocellulose (NC), nitroglycerin (NG), nitromethane (NM), pentaerythritol tetranitrate (PETN), picric acid (PA), cyclotrimethylene trinitramine (RDX), trinitrophenylmethylnitramine (“Tetryl”), 2,2,2-trinitroethyl 4,4,4- trinitrophenylmethylnit
• Examples of fuels included in these compositions are aluminum and other metals or metal hydrides.
• Examples of binders and other additives, which are also part of the fuel, are polysulfides, polyurethanes, polybutadienes, triacetin, resorcinol, and graphite. These lists are not exhaustive, but merely illustrative of the types of materials included in compositions which can be treated in accordance with this invention.
• compositions to which the invention is applicable are solid in form prior to treatment, and certain of these will be capable of desensitization in solid form, depending on the composition itself and the electrolysis apparatus. In most cases involving solid compositions, however, best results will be obtained by first the composition to a slu ⁇ y and performing electrolysis on the slurry.
• the liquid used to form the slu ⁇ y will be any liquid capable of conducting an electric current ionically, preferably a polar liquid capable of dissolving salts, acids or bases to form an ionically conducting electrolyte.
• the liquid be one which will partially dissolve one or more of the active components of the composition, Le., those which are the source of the detonation risk. This will help leach out some of the active component and enhance its decomposition when subjected to the electric current
• polar liquids are water and aqueous media in general, low molecular weight alcohols such as methanol, ethanol, propanol, isopropanol, butanol and isobutanol, and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.
• low molecular weight alcohols such as methanol, ethanol, propanol, isopropanol, butanol and isobutanol
• ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.
• Water is preferred for purposes of low cost, safety and ease of use.
• the amount of liquid used to form the slurry is also not critical, and will be selected primarily on the basis of practical considerations of equipment scale, and ease of handling, processing and transferring. In most cases, the proportion of liquid actually used will range from about 30% to about 90% by volume of the slurry, with amounts between about 50% and about 75% preferred.
• additives which are not part of the composition itself may be incorporated in the slurry to enhance and accelerate the electrolysis.
• Such additives may for example be materials that increase the electrical conductivity of the slurry, and also materials that degrade the nitro-, nitramine- and nitrato- containing compounds present in the composition.
• Examples of such additives are alkali metal, alkaline earth metal and ammonium hydroxides or other water-soluble inorganic bases, water-soluble acids and salts, and sulfides, sulfates, sulfites and polysulfides of alkali metals, alkaline earth metals and ammonia.
• alkali or alkaline earth metals are sodium, potassium, and calcium.
• current density is used herein to denote the amount of current per unit area of electrode surface. In processing cells where the two electrodes differ significantly in surface area, the surface area used in determimng the current density is that of the electrode which offers the highest resistance to current flow.
• the process is to be conducted under such conditions of time, temperature and current density that the reactions which take place occur in a non- self-propagating manner, __., are not subject to spontaneous acceleration but are driven essentially entirely by the electric current
• the optimum or preferred current for any particular application of this invention will depend on the scale of the process, including the amount of material to be treated, the size of the equipment and the time period available for the treatment In most cases, however, effective results are obtained with a current density not exceeding about 0.30 amps/cm 2 , preferably not exceeding about 0.20 amps/cm 2 . Currents as low as 0.01 amps/cm 2 will be useful and practical in certain small scale systems.
• the preferred range for most systems is therefore about 0.01 amps/cm 2 to about 0.20 amps/cm 2 , with about 0.01 amps/cm 2 to about 0.03 amps/cm 2 particularly preferred.
• the applied potential may be lowered in the direction of the minimum activation potential, since progressively less reducing agent is required.
• the potential is adjusted at intervals to the lowest potential that will maintain the maximum negative slope for the depletion curve.
• the temperature is not critical, the only consideration being that the temperature itself not create a hazardous situation or cause any substantial amount of vaporization.
• the rate of desensitization increases with increasing temperature, the invention is readily and adequately conducted at ambient or room temperature, ie., 20 to 25°C. Cooling of the system during the process is generally not required, and the temperature will frequently rise due to the electric current itself. In most cases, the rise will not be sufficient to require temperature control.
• the temperature is maintained at an elevated level. For aqueous systems, a preferred temperature range is above about 140°F (60°C) yet safely below the boiling temperature of 212°F (100°C). Elevated temperature increases the reaction rate and reduces the decomposition activation energy requirements. The increased reaction in the slurry further increases the cell conductivity which lowers the electrode overvoltage requirements.
• the length of time during which the desensitization is permitted to proceed will be any duration which will achieve the desired degree of desensitization at the current used. In most cases, the duration will be greater than about twenty minutes, preferably greater than about 1 hour, and most preferably greater than about 4 hours.
• the electrodes may be constructed of any of the materials which are known for use as electrodes. The actual material to be used may be varied widely. Selection of the material for any particular application, however, will be influenced by a number of factors. For example, preferred materials will generally be those which are the least susceptible to degradation from the passage of electric current In certain systems, furthermore, the preferred materials will be those which are inert to the electrochemical reactions which will occur during the process. In certain other systems, it will be preferable to use electrodes which themselves become reduced or oxidized during the process. In still other systems, it will be preferable to use electrodes which absorb reactants or products of the electrochemical reactions occurring in the process.
• the configuration and spacing of the electrodes and the design and construction of the electrolysis cell are not critical, and will be varied according to the needs of the system.
• the cell may for example be a single-vessel cell, a partitioned cell two half-cells.
• the cell efficiency will depend at least in part on the electrode surface area, since the electrochemical reactions take place at the electrode surfaces.
• the electrodes will generally be spaced from about 1cm to about 100cm apart, preferably from about 3cm to about 30cm.
• Electrolysis may be conducted using any of a variety of electric cunent profiles.
• the actual type of cunent may be varied, although certain types may be preferable for treating certain compositions.
• alternating cunent, direct cunent or pulsed cunent may be used.
• the frequency may vary and is not critical.
• pulsed cunents each pulse will be direct cunent.
• the pulse duration however may vary.
• a computer is particularly useful for control of pulse switching and duration.
• the degree to which the composition is electrolyzed in the practice of the invention is also noncritical and may vary.
• FIG. 1 one example of an electrolytic cell 11 in which the process of the invention may be performed is shown.
• the slu ⁇ y 12 to be desensitized is placed in an open-top vessel 13.
• the vessel 13 is supported on a turntable 14, electrically powered to rotate.
• the turntable may be constructed with the capability of being raised or lowered to place it in contact, or remove it from contact, with the other components of the structure entering the vessel through its opening from above.
• a support stand 15 Placed over the turntable 14 and vessel 13 are a support stand 15, constructed to span the vessel opening. Secured to the stand are a stiner bar 16 and electrodes 17, 18, arranged to extend downward into the interior of the vessel 13 and thereby be submerged in the slu ⁇ y 12.
• the stiner bar 16 is rigidly attached to a first tier 19 of the support stand and remains stationary as the turntable 14 rotates.
• the apparatus shown in FIG. 1 further includes a mechanism for scraping the electrodes clean of deposited solids.
• the electrodes in this example are rod-shaped, and the scraping mechanism consists of a pair of scraper cages 22, 23, each sunounding one of the electrodes with a small gap as clearance.
• the yoke 24 which joins the electrodes is suspended from the second tier 25 of the support stand by a movable rod 26 whose motion is controlled by an air cylinder 27, which may for example be a double-acting short stroke actuator cylinder.
• the movable rod 26 is shown in the extended position.
• the actuator cylinder 27 retracts the rod 26, moving the electrodes upward inside the stationary scraper cages.
• the actuator cylinder holds the rod in this retracted position until a further signal actuates the return of the rod to the extended position. It will be clear from the drawing that only a short range of motion of the rod is needed for the electrodes to move sufficiently to be scraped by the scraper cages.
• the gap is filled with water 66 which also covers the upper electrode 63. Liquor from the propellant maceration operation may be used as the water.
• the two electrodes are electrified by appropriate voltage supply lines 67, 68.
• the lower electrode 62 serves as the cathode and the upper electrode 63 serves as the anode.
• the cunent was turned off and the slurry removed from the plastic container. Water was then removed from the slurry by decantation and evaporation, to return the propellant materials to solid form. Analyses and standard sensitivity tests were then performed to compare the treated material with the starting material prior to being formed into the slurry. The analyses included determinations of the levels of ammonium perchlorate, HMX and NG, and the sensitivity tests included a Naval Ordnance Laboratory Card Gap Test and a Bureau of Mines Dropweight Impact Test Each of the sensitivity tests was conducted according to standard procedures well known and readily available to those skilled in the art The Card Gap Test was conducted using zero cards.

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• Chemical & Material Sciences (AREA)
• Electrochemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Organic Chemistry (AREA)
• Water Supply & Treatment (AREA)
• Environmental & Geological Engineering (AREA)
• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Toxicology (AREA)
• Emergency Management (AREA)
• Business, Economics & Management (AREA)
• General Health & Medical Sciences (AREA)
• Health & Medical Sciences (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Applications Claiming Priority (4)

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• 1992
  • 1992-01-24 WO PCT/US1992/000551 patent/WO1992013117A1/en not_active Application Discontinuation
  • 1992-01-24 JP JP4505421A patent/JPH0747832B2/ja not_active Expired - Lifetime
  • 1992-01-24 GB GB9220055A patent/GB2258245B/en not_active Expired - Fee Related
  • 1992-01-24 DE DE4290097T patent/DE4290097T1/de not_active Withdrawn
  • 1992-01-24 EP EP19920905614 patent/EP0522140A4/en not_active Withdrawn
  • 1992-01-24 UA UA93003852A patent/UA26910C2/uk unknown

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