Cheddite
Cheddite (French cheddite ) is the name of a group of non-homogeneous chlorate explosives that were developed and produced in France from the end of the 19th century and later in Great Britain and Germany . The name is derived from the district of Chedde in the municipality of Passy ( Haute-Savoie department ), where Cheddit was first produced. The chemist EAG Street developed the first cheddite in 1897. As a mining explosive, cheddites gained great industrial importance, but are no longer used for it today. The plastic explosive gelatine cheddite has been used for military purposes since the middle of the 20th century .
Composition and types
Cheddites are similar in composition to Sprengel's chlorate explosives . By incorporating the chlorates in various binders such as oils, resins or gelatine, a relatively high level of insensitivity to shock and impact is achieved. The hygroscopicity of the often used cheap sodium chlorate has a disadvantage , which can be avoided by using the more expensive potassium chlorate .
A distinction is made between different types of cheddites, common in each case are a chlorate and an oily or resinous binder, which envelops the chlorate and thus reduces the sensitivity to impact. Most types also contain one or more nitro compounds that are oxidized by the chlorate in the explosion and some of them have explosive properties themselves.
| component | Type 41 | Type 60 | Type 03 | Street BP 9970 | Street DP 100522 | Street DP 117051 | Street DP 118102 | Bonnet DP 124237 | Turpin's pyrodialyte | Gelatin cheddit |
|---|---|---|---|---|---|---|---|---|---|---|
| Potassium chlorate | 80% | 80% | - | 80% | 80% | 80% | 80% | 80% | 84% | - |
| Sodium chlorate | - | - | 79% | - | - | - | - | - | - | 79% |
| castor oil | 8th % | 6% | 5% | 5% | - | - | - | - | - | 5% |
|
Sulphured mineral oil (S) |
- | - | - | - | 10% | 10% | 10% (S) | - | - | - |
|
Resin , tar (H / T), stearic acid (S) |
- | - | - | - | - | - | - | 12% (S) | 14% (H / T) | - |
|
Nitronaphthalene (NN) Dinitrotoluene (DNT) Dinitrobenzene (DNB) Trinitrotoluene (TNT) Picric acid (PS) |
12% NN | 12% NN 2% PS |
16% DNT | 13% NN 2% DNT |
10% NN | 10% NN | 10% NN | 3% DNB | - | 2% DNT 14% TNT |
|
Detonation speed |
<3175m / s | 3175 m / s | > 3175m / s | - | - | - | - | - | - | - |
| Remarks | instead of NN also azobenzene ; sometimes small amounts of coal powder or starch | small amounts of nitroglycerin , nitrocellulose or aniline pricrate | instead of NN also azobenzene | 2% ethanol to improve homogeneity | Preparation with nitrocellulose to a plastic-like mass | |||||
| Swell ,, | ||||||||||
Manufacturing
Depending on the type, the nitro compound is first dissolved in the oil or resin at 40-80 ° C and then the heated chlorate is added while stirring. Other components are sometimes added in small amounts, such as coal powder, sulfur or ethanol , in order to improve the homogeneity or the properties of the explosives. The resulting mass is mechanically mixed or kneaded and crushed.
Properties and use
Due to the high chlorate content, cheddites are sensitive to friction, impact and fire, but to a much lesser extent than mixtures of chlorates with sulfur or charcoal. In a drop hammer test with a hammer weighing five kilograms , the type 60, which is similar to dynamite , detonated with a 50% probability at a height of 0.253 m. Type 41, however, only detonated (with a 50% probability) at a fall height of 0.352 m. The explosives could be stored for several years.
Cheddites were used on a large scale as explosives in mining , road and tunnel construction . The Type 60 was used for blasting in very hard rock; Type 41 was mainly used to split stones without breaking them completely. Gelatin cheddit is made as a military plastic explosive in Switzerland .
Were ignited by cheddite detonator , with about 0.5 to 1.5 grams of mercury fulminate ( mercury (II) -fulminat ).
Individual evidence
- ^ A b c d Rudolf Biedermann: The explosives: their chemistry and technology. 2nd edition, BG Teubner, Leipzig, 1910, p. 66.
- ^ Wissenschaft-Online-Lexika: Entry on Cheddite in the Lexikon der Chemie, accessed on August 6, 2009.
- ^ A b Henry Burnell Faber: Military Pyrotechnics, Volume 3. BiblioBazaar, LLC, 2009, ISBN 978-1-103-27980-7 , p. 127.
- ↑ a b c United States Dept. of the Army: Military explosives. Headquarters Dept. of the Army, 1992.
- ↑ George Stuart Brady, Henry R. Clauser, John A. Vaccari: Materials Handbook: an encyclopedia for Management, technical professionals, purchasing and production Management, technicians, and supervisors. 15th edition, McGraw-Hill Professional, 2002, ISBN 978-0-07-136076-0 , p. 890.