Liquid explosives, impact sensitivity

Extremely explosive, heat- and shock-sensitive as liquid or vapour [1], During determination of the impact-sensitivity of the confined material, rough handling of the container caused ignition. The material should only be handled in small quantity and with great care [2]. 

The cyanide is a friction- and impact-sensitive explosive, and may initiate detonation of liquid hydrogen cyanide. Other heavy metal cyanides are similar. 

Accidental admixture of oxygen gas with unstabilised liquid tetrafluoroethylene produced a polymeric peroxide which was powerfully explosive, and sensitive to heat, impact or friction [1], Removal of oxygen by treatment with pyrophoric copper to prevent explosion of tetrafluoroethylene has been claimed [2],... 

Mechanical impact on a road surface on to which liquid oxygen had leaked caused a violent explosion [1], Anecdotal evidence that there have been several like incidents is given [2], Mixtures of asphalt and liquid oxygen were shown to be impact-sensitive on the small scale, but on the larger scale a detonator was necessary to initiate mild explosion of liquid oxygen on a layer of asphalt [3], Oil,... 

Modified Impact Tests for Liquid Explosives (7) Explosion Temperature Test (pp 7-8 and Fig 8, p 39) Decomposition Temperature Test (8) Sensitivity to Initiation by Sand Test (pp 9-11 and Figs 9 10,... 

MagyKemFolyoirat 7(8), 346-52(1956) (Initiation of expln of Amm Perchlorate with Cr20j-Ti02 catalysts) 19) P.E. Skidmore D.E. Thompson, "Development of an Improved Method for Determining Impact Sensitivity of Liquid Explosives , ABL Rept ABL/X-10 (1957) 19a) J.E. Sin-... 

Explosives Sensitivity Data. Card-gap and projectile sensitivity, data are presented by Watson (Ref 1) for a wide variety of expl compns tested at the USBurMines laboratories in more or less standard test geometries. The results of both tests are in good agreement in that they provide the same sensitivity ordering fbr different subclasses of expls. Least sensitive were homogeneous liquids that did not exhibit a tendency, to undergo low-velocity detonation, AN-FO (Ammonium Nitrate-Fuel Oil), and most cast military expls. Of intermediate sensitivity were pressed and powdered military expls, cast Pentolite, permissible and nonpetmissible water-based expls, and one commercial two-component expl. The most sensitive were permissible and nonpermissible Dynamites and expls susceptible to low-velocity detonations Refs I) R.W. Watson, 1 Card-Gap and Projectile Impact Sensitivity Measurements, A Compilation , USBurMines Information Circular 1C 8605(1973)... 

Picatinny arsenal (PA) impact apparatus The sample which is placed in the depression of a small steel die-cup and then capped by a thin brass cover, is used in this test. The value of minimum height at which at least one out of ten trials results in explosion gives impact sensitivity. In the case of liquids, it is filled in a die-cup and tested in a manner similar to solids. 

Metal Azides. Vapor with silver or sodium azide forms explosive bromine azide.10 Metals. Impact-sensitive mixtures are formed from lithium or sodium in dry bromine.11 Potassium, germanium, antimony, and rubidium ignite in bromine vapor.12 Violent reaction occurs with aluminum, mercury, or titanium.13 Methanol. Vigorously exothermic reaction on mixing the liquids.14 Nonmetal Hydrides. At room temperature, violent explosion and ignition occur with silane and its homologs15,16 and with germane.17... 

The following explosive props are given in Urbahski (Ref 4), Blatt (Ref 6) 8c ADL (Ref 7) Impact Sensitivity — much more sensitive than NG or NGc when absorbed on filter paper the pure liquid can be detonated with a hammer. 

NJ. The following tests are described Impact Test with PicArsn Apparatus (pp 2 to 4 with Figs 1, 2, 3 4 on pp 32 to 35) Impact Test with USBurMines App (4 to 7 with Figs 5, 6 7 on pp 36 to 38) Modified Impact Tests for Liquid Explosive Made with BurMinesApp and with PicArsnApp (7) Explosion Temperature Test (7 to 8 with Fig 8 on p 39) Decomposition Temperature Test (8) Sensitivity to Initiation as Determined by Sand Test (9—II with Figs 9, 10, 11 12 oh pp 40—3) Modified Sand Test for Liquid Explosives (12—14) Electrostatic Sensitivity Test (14—15 and Figs 13 14 on pp 44 45) Brisance by Sand Tests (16—17) Initiation Efficiency by Sand Test (17) Stability Tests, which include 75°C International Test (18) 82.2°C KI Test (19) 100° Heat Test (19) 90°, 100° 120°C Vacuum Stability Tests (19—22 and Figs 15, 16 17 on pp 46—8) 65.5°C Surveillance Test (22—3 and Fig 18 on p 49) ... 

Measurement of Impact Sensitivity of Liquid Explosives and Monopropellants... 

Johansson and co-workers (7, 8, 9) have shown that heat transfer from a compressed spherical bubble does not increase the temperature of its liquid surface sufficiently to account for the impact sensitivity of liquid explosives the high sensitivity of nitroglycerin is postulated as arising from the fact that small droplets are readily formed by the impact and ignited by the compressed air. Bolkhovitinov (1) postulated crystallization of the liquid under the impact pressure, with the phase transition causing the temperature increase which causes explosions. Bowden (3) favors the adiabatic compression of gas bubbles combined with the dispersion of the explosive into fine particles as the mechanism for initiation by mechanical impact. 

A significant conclusion from the data on the importance of compression ratio in initiating explosion of nitroglycerin is that processing or handling liquid explosives and monopropellants under reduced pressure may introduce a hazard by sensitizing the liquid to weak impacts. 

Of the approximately 12 motion pictures we made of the impact initiation process, all show that the structure of the air bubble is broken down and replaced by a turbulence area. Ignition occurs at the former site of the bubble after an induction period. The compression ratio of the air bubble appears to be the major factor determining probability of initiation by impact. The mechanism for impact initiation of nitroglycerin therefore appears to be a quasi-adiabatic compression of the gas, with heat transfer accelerated by spray formation. Hot spots formed at the former site of the bubble undergo an accelerating exothermic reaction which proceeds to a deflagration. The possibility that liquid explosives under reduced pressure may be sensitized to weak impacts must be considered. 

DOT CLASSIFICATION 4.3 Label Danger When Wet, Corrosive, Flammable Liquid SAFETY PROFILE Moderately toxic by inhaladon. Corrosive. A severe irritant to skin, eyes, and mucous membranes. Ignites spontaneously in ait. A very dangerous fire hazard when exposed to heat or flame. Forms impact-sensitive explosive mixtures with potassium permanganate, lead(II) oxide, lead(TV) oxide, copper oxide, silver oxide. To fight fire, use water, foam, CO2, mist. When heated to decomposition it emits toxic fumes of CL. See also CHLOROSILANE. 

DOT CLASSIFICATION 6.1 Label Poison SAFETY PROFILE Poison by ingestion, subcutaneous, intravenous, and intraperitoneal routes. Human systemic effects by ingestion nausea or vomiting, hypermotility, diarrhea, kidney changes, somnolence. Hydrolyzes to toxic fumes. A friction- and impact-sensitive explosive. It may initiate detonation of liquid hydrogen cyanide. Incompatible with fluorine, magnesium, sodium nitrite. When heated to decomposition it emits very toxic fumes of Hg, NO, and CNT See also CYANIDE and MERCURY COMPOUNDS. 

Erythritol tetranitrate (Figure 3.26) is a solid. It forms colorless crystals and has a melting point around 61°C. It is made by dissolving erythritol in nitric acid and then precipitating out the explosive by adding sulfuric acid to the solution. It is not nearly as impact sensitive as nitroglycerine or the other liquids mentioned. It finds little use as a common explosive. 

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