Difference between revisions of "Black powder"
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In most of the world, the sale and own of black powder is forbidden, except under a certain amount, or is only permitted during New Year's Eve, as fireworks. Persons who work in the explosives domain may acquire a permit to use black powder. | In most of the world, the sale and own of black powder is forbidden, except under a certain amount, or is only permitted during New Year's Eve, as fireworks. Persons who work in the explosives domain may acquire a permit to use black powder. | ||
| − | Modern ammunition no longer uses gunpowder, and instead relies on smokeless powders. | + | Modern ammunition no longer uses gunpowder, and instead relies on smokeless powders. One exception is shotgun ammo: in certain countries black powder cartridges are still used for shotguns. |
==Preparation== | ==Preparation== | ||
Revision as of 11:15, 26 August 2015
Black powder, more commonly known as gunpowder, is one of the most known chemical explosives. It is a mixture of potassium nitrate, charcoal and sulfur, in a 75:15:10 ratio. The term black powder is usually preferred, to distinguish it from smokeless powder. It is classified as low explosive.
Contents
Properties
Chemical
Black powder will burn fast if ignited, even in vacuum, and will explode if ignited in a closed container.
A general reaction can be considered:
- 7 KNO3 + C7H4O + 3 S → K2CO3 + K2SO4 + 3/2 K2S + 4 CO2 + 2 CO + SO2 + 2 H2O + 3 N2
Physical
Black powder is, as its name suggests, a black powder, extremely fine (if properly grounded), with a slight metallic taste and a weak smell, usually from the sulfur and/or charcoal type used. It is considered an insoluble material (sulfur and saltpeter have poor solubility in all of their mutual solvents and charcoal is completely insoluble in any solvents). Gunpowder has a pH of 6.0 - 8.0. It's specific gravity varies between 1.70 - 1.82 (via mercury method) and 1.92 - 2.08 (via pycnometer). The standard black powder has an autoignition temperature of 464°C.
Availability
In some countries, such as United States and the Russian Federation, black powder is sold in gun stores, though some might only sell smokeless powder labeled as black powder or grains. Purchasing black powder may or may not require a license (such as a license to own and use smoothbore firearms or to manufacture ammunition), depending on the jurisdiction in question.
In most of the world, the sale and own of black powder is forbidden, except under a certain amount, or is only permitted during New Year's Eve, as fireworks. Persons who work in the explosives domain may acquire a permit to use black powder.
Modern ammunition no longer uses gunpowder, and instead relies on smokeless powders. One exception is shotgun ammo: in certain countries black powder cartridges are still used for shotguns.
Preparation
Potassium nitrate, sulfur and charcoal are first grounded separately. In a mortar, a mixture of these three materials in a weight proportion of 75% for potassium nitrate, 15% for charcoal, and 10% sulfur is added. The mortar must be made of a spark-free material. The mixture is CAREFULLY grounded until it becomes as fine as flour. This is the most dangerous part in the manufacture of gunpowder, as any static spark can ignite the fine powder and cause an explosion. If a ball mill is used, spark free ball mills, such as lead-antimony are a must. Another tip would be to add a little water, to reduce the chance of ignition. Other volatile solvents can also be added, though preferably non-flammable ones. The best type of charcoal for making gunpowder is made from softwood, such as willow. Avoid hardwood as it contains too much ash.[1] Pure carbon, such as amorphous carbon or graphite, requires a higher temperature for ignition than charcoal, and it's best to avoid using it.
Other and unconventional black powders
If potassium nitrate is unavailable, sodium nitrate can be used instead. This black powder tends to burn slower.
Replacing the potassium nitrate with a stronger oxidizer, such as potassium chlorate or potassium perchlorate increases the explosive power of the gunpowder, however potassium chlorate and sulfur mixtures are sensitive and are dangerous to mill or handle safely. Chlorate and perchlorate mixtures may corrode the gun barrel due to the hydrogen chloride gasses released during the detonation.
Red phosphorus can also be used instead of sulfur. The type of mixture without charcoal is known as Armstrong's mixture.
White gunpowder is a mixture of potassium chlorate, potassium hexoferrcyanate and sugar, in a 50:25:25 weight ratio.
Projects
- Blasting caps
- Fuses
- Black match
- Rockets
- Historic firearm models (handcannon, arquebus, matchlock, etc.)
Handling
Safety
Gunpowder is a dangerous explosive and should only be handled by people who know what they're doing. The milling procedure is known to cause detonations of the powder, so this MUST NOT be done by any amateur. If gunpowder ever ignites, it is extremely difficult to extinguish. Water can be used to put out fires and to soak any spills to prevent fire. Burning black powder gives off sulfur dioxide, which is very toxic. NEVER SMOKE NEAR GUNPOWDER CONTAINERS! While is difficult to ignite most flammable materials with a lit cigarette, black powder contains its own oxidizer and can ignite with any hot body, even if it doesn't have a flame.[2]
Storage
Storage of gunpowder is best done in wood or cardboard containers. The classic wooded keg is a good example. Gunpowder "kegs" should never be placed in the same room with flammable materials such as solvents, and instead should be kept in special rooms, away from anything and anyone. Metal containers and plastic are sometimes used to store black powder, such as military powder flasks and horns.
Disposal
Black powder can be burned, though this will produce sulfur dioxide gases.
Gunpowder may be safely discarded in the ground, as its components are already used as fertilizers. Many gun owners have done that with old powder, claiming no negative effects on the land.[3]
References
- ↑ http://www.dangerouslaboratories.org/foxfire5.html
- ↑ http://web.mit.edu/rocketteam/www/usli/MSDS/Black%20Powder.pdf
- ↑ http://www.taurusarmed.net/forums/lounge/67682-gunpowder-fertilizer.html
