US3336171A - Ammonium nitrate explosive compositions containing (metal-excess chloride) combustion catalyst - Google Patents

Ammonium nitrate explosive compositions containing (metal-excess chloride) combustion catalyst Download PDF

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Publication number
US3336171A
US3336171A US526818A US52681866A US3336171A US 3336171 A US3336171 A US 3336171A US 526818 A US526818 A US 526818A US 52681866 A US52681866 A US 52681866A US 3336171 A US3336171 A US 3336171A
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United States
Prior art keywords
metal
ammonium nitrate
chloride
compositions containing
combustion catalyst
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Expired - Lifetime
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US526818A
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English (en)
Inventor
Arthur G Keenan
Jr Karl J Notz
Nicholas B Franco
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Research Corp
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Research Corp
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Priority to US526818A priority Critical patent/US3336171A/en
Priority to GB1252/67A priority patent/GB1127871A/en
Priority to FR92035A priority patent/FR1509401A/fr
Priority to BE692948D priority patent/BE692948A/xx
Priority to DE19671646327 priority patent/DE1646327B1/de
Application granted granted Critical
Publication of US3336171A publication Critical patent/US3336171A/en
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    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06BEXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B23/00Compositions characterised by non-explosive or non-thermic constituents
    • C06B23/007Ballistic modifiers, burning rate catalysts, burning rate depressing agents, e.g. for gas generating
    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06BEXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B31/00Compositions containing an inorganic nitrogen-oxygen salt
    • C06B31/28Compositions containing an inorganic nitrogen-oxygen salt the salt being ammonium nitrate

Definitions

  • This invention relates to ammonium nitrate gas producing or explosive compositions, and more particularly to ammonium nitrate compositions having an improved decomposition rate.
  • Ammonium nitrate is widely used as a component of explosive compositions often in admixture with an oxidizable material such as cellulose or related materials, various other polysaccharides, carbohydrates and oxidizable organic compounds, and carbon and sulphur.
  • an oxidizable material such as cellulose or related materials, various other polysaccharides, carbohydrates and oxidizable organic compounds, and carbon and sulphur.
  • primers or detonators such as nitr-osta-rch, nitrocellulose, nitroglycerine and trinitrotoluene may also be included in these compositions.
  • combustion catalysts Another approach utilized for improving the sensitivity of an ammonium nitrate explosive is the incorporation of a combustion catalyst into the explosive composition.
  • the most commonly employed combustion catalysts contain chromium usually in the form of chromate or other readily available salts of chromium.
  • Compositions containing iron, nickel and cobalt have been described for use in conjunction with chromium.
  • Other compositions containing various metals have also been described as combustion catalysts.
  • the present invention is an ammonium nitrate gas producing or explosive composition containing at least 0.05% by weight of a metal and at least one chloride anion per metal atom in excess of the ratio of chloride anion to metal atom that would be obtained by adding the metal as its chloride salt.
  • the metal may be supplied in free or combined form.
  • a readily available salt containing the metal as a cation or as part of the anion.
  • suitable salts would include nitrates, carbonates, sulfates, chromates and the like.
  • ammonium nitrate melt dissolves most metals by forming the metal nitrate.
  • the decomposition rate of ammonium nitrate gas producing or explosive compositions is improved by the incorporation of at least 0.05% of a metal usually provided as its salt and excess chloride anion as described more fully below.
  • the improved catalytic effect of the present invention increases with increasing the metal content of the explosive composition until either the diluent effect of the metal salt or its limited solubility in the system begins to decrease its effectiveness.
  • These factors vary widely With the particular metal salt employed and there is no theoretical upper limit for the amount of metal which may be employed. Satisfactory explosive compositions containing as high as 20% by Weight of the metal have been prepared and tested. Compositions containing about 1 to 5% by weight of the metal would be the most useful.
  • ammonium nitrate compositions containing at least one chloride anion per metal atom in excess of the ratio obtained by adding the metal as chloride exhibit the improvement of the present invention.
  • the rate of decomposition increases markedly as the ratio of chloride anions to metal atoms increases up to about 10:1 and relatively little further improvement, and possibly some decrease, is noted as additional chloride is added.
  • FIG. 1 Data illustrating this is presented in graphical form in FIG. 1 wherein the maximum temperature obtained on decomposing ammonium nitrate containing 0.1% by weight of a metal is plotted as a function of the amount of chloride anions present.
  • the particular metal employed was copper added as its carbonate; generally speaking other metals and metal salts behave in a similar manner.
  • the rate of improvement obtained using metal-chloride combustion catalysts in an ammonium nitrate composition according to the present invention with various metals was determined.
  • the metals are:
  • Chromium Titanium Copper Lead Silver Manganese Nickel Mercury Iron Bismuth Gold Platinum Palladium Zinc Cobalt Cadmium Cerium Aluminum Zirconium Chromium, copper, silver and nickel are particularly effective.
  • Metals having a standard oxidation potential above 2.0 volts, i.e., the alkali metals such as lithium, potassium, sodium, et cetera, are much less effective.
  • Chloride ion is by far the most effective halide for use in conjunction with metals in the synergistic catalytic combinations of the present invention.
  • a slight beneficial effect has been noted when bromide is used in place of chloride, but this effect is not of practical interest when considered in the light of the relative cost of bromide salts and chloride salts.
  • the substitution of iodide or fluoride for chloride does not give any appreciable synergistic effect.
  • the particular cation employed as the chloride carrier is not critical, but for reasons of economy and convenience, the chlorides of sodium, potassium and ammonium are preferred.
  • the improved compositions of the present invention are made by incorporating the metal containing additive and the chloride anion containing additive into an ammonium nitrate explosive composition by any conventional means, for example, by milling or dry mixing the ingredients. The mixture may then be shaped or pressed or otherwise prilled to the form of compacted grains. Regular shaped particles are preferably prepared by adding the ingredients to each other in a fused or molten condition and pressing the resultant paste into suitable molds. The particles are allowed to cool before being removed from the mold.
  • ammonium nitrate as used herein is intended to include ordinary commercial grade ammonium nitrate,
  • compositions may contain a small amount of impurities and are generally provided with a small amount of moisture resisting material such as petrolatum or paraffin.
  • the curves shown in FIG. 2 of the drawing are graphs of temperature against time obtained on a potentiometric recorder from a thermocouple set in an ammonium nitrate sample held in a furnace at 185 C.
  • the method employed for measuring temperature was generally similar to that used in standard differential thermal analysis. Since the temperature differentials obtained were rather large, it was not necessary to utilize certain of the refinements of conventional differential thermal analysis.
  • the thermocouple reference junction was located in a constant temperature ice bath rather than in an inert sample in the furnace itself, and the furnace was programmed to maintain a constant temperature of 185 rather than rise continually. None of these variations made any essential difference in the results obtained since more refined procedures would show exactly the same relative behavior for the various systems studied.
  • thermographs shown in FIG. 2 were obtained by weighing six grams of air-dried ammonium nitrate and the required amounts of other constituents into a glass reactor tube, shaking to achieve some degree of mixing and inserting the tube into a furnace at 185 C.
  • the sample melted circa 160170 depending on the particular composition being tested, reached 185 in about 30 minutes total time and took off in another to minutes, again depending on the composition being tested.
  • These parameters apply to the particular apparatus and conditions, especially the furnace temperature, employed.
  • thermographic methods give only relative results, the absolute values of which are dependent on the specific apparatus and operating parameters. However, the relative behavior of the samples in a given system remains the same.
  • curve A shows the results obtained using ammonium nitrate alone without any additives and confirms the relative insensitivity of pure ammonium nitrate.
  • Curve B shows the relatively small improvement obtained using only a metal additive (about 0.1% by weight added as its salt; the particular metal employed Was chromium but other metals give similar results).
  • Curve C shows the improvement obtained by using 5 mole percent sodium chloride as the sole additive.
  • Curves D, E, F and G show the synengistic improvement obtained when compounds of chromium, copper, silver and nickel, respectively, are used as additives together with sodium chloride in a chloride/metal atom ratio of 37:1. The more active the metal, the shorter the induction period and the higher the peak obtained.
  • An explosive composition consisting essentially of ammonium nitrate, at least 0.05% by weight of a metal and at least one chloride anion per metal atom in excess of the ratio of chloride anion to metal atom that would be obtained by adding the metal as its chloride salt.
  • composition according to claim 1 wherein the metal is chromium, copper, silver or nickel.
  • composition according to claim 1 wherein the metal is in the form of salt.
  • composition according to claim 1 containing at least ten chloride anions per metal atom.
  • composition according to claim 1 containing 1 to 5% by weight of a metal.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Catalysts (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Paints Or Removers (AREA)
US526818A 1966-02-11 1966-02-11 Ammonium nitrate explosive compositions containing (metal-excess chloride) combustion catalyst Expired - Lifetime US3336171A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US526818A US3336171A (en) 1966-02-11 1966-02-11 Ammonium nitrate explosive compositions containing (metal-excess chloride) combustion catalyst
GB1252/67A GB1127871A (en) 1966-02-11 1967-01-10 Ammonium nitrate explosive compositions
FR92035A FR1509401A (fr) 1966-02-11 1967-01-20 Compositions explosives à base de nitrate d'ammonium, améliorées
BE692948D BE692948A (en)van) 1966-02-11 1967-01-20
DE19671646327 DE1646327B1 (de) 1966-02-11 1967-02-07 Explosivstoffgemisch auf der Basis von Ammoniumnitrat

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US526818A US3336171A (en) 1966-02-11 1966-02-11 Ammonium nitrate explosive compositions containing (metal-excess chloride) combustion catalyst

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US3336171A true US3336171A (en) 1967-08-15

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US (1) US3336171A (en)van)
BE (1) BE692948A (en)van)
DE (1) DE1646327B1 (en)van)
FR (1) FR1509401A (en)van)
GB (1) GB1127871A (en)van)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19844350C1 (de) * 1998-09-28 2000-03-23 Fraunhofer Ges Forschung Verfahren zur Herstellung von phasenstabilisiertem Ammoniumnitrat

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US254893A (en) * 1882-03-14 Holder
US2154416A (en) * 1936-08-10 1939-04-11 Ici Ltd Nondetonating blasting explosive
CA528513A (en) * 1956-07-31 Taylor James Explosive compositions
US2816012A (en) * 1955-04-04 1957-12-10 Drackett Co Heat-producing compositions
US2829958A (en) * 1954-04-26 1958-04-08 Ici Ltd Explosive compositions

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE305059C (en)van) *

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US254893A (en) * 1882-03-14 Holder
CA528513A (en) * 1956-07-31 Taylor James Explosive compositions
US2154416A (en) * 1936-08-10 1939-04-11 Ici Ltd Nondetonating blasting explosive
US2829958A (en) * 1954-04-26 1958-04-08 Ici Ltd Explosive compositions
US2816012A (en) * 1955-04-04 1957-12-10 Drackett Co Heat-producing compositions

Also Published As

Publication number Publication date
GB1127871A (en) 1968-09-18
FR1509401A (fr) 1968-01-12
BE692948A (en)van) 1967-07-20
DE1646327B1 (de) 1970-10-15

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