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Magnesium
| Magnesium is the chemical element in the periodic table that has the symbol Mg and atomic number 12. Magnesium is the eighth most abundant element and constitutes about 2% of the Earth's crust, and it is the third most plentiful element dissolved in seawater. This alkaline earth metal is primarily used as an alloying agent to make aluminium-magnesium alloys. |
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The Goldschmidt process, patented in 1895, has been widely used since then. It is better known as thermite or Thermit, a trade name. A mix mainly of aluminium powder and iron oxide is packed into a crucible and ignited by a magnesium ribbon and a starter mass, or some other means. It is not easy to light. The vigorous reaction results in a slag of aluminium oxide on very hot molten iron, up to 3000°C. The iron flows into a mold that is part of the crucible, usually to perform a weld. The iron oxide is the oxidizer, and the aluminum metal the fuel, in the gasless reaction. The same idea can be used for other metals, such as chromium, manganese and ferrotitanium, and also for a nefarious incendiary device.
A great hazard in an around explosives is heat.
Some explosives ignite at temperatures substantially lower than those required to ignite wood, paper, or fabrics. The ignition of explosives frequently results in violent reactions. Every effort must be made to maintain normal temperatures around ammunition and explosives.
Fires in ammunition dump areas may be due to a number of causes. The following are moat common: dry grass, leaves, and underbrush ignited by sparks from locomotives, carelessly discarded cigarettes, campfires, or unprotected smokestacks.
Deterioration of explosives and ammunition normally occurs at such a slow rate that most of them remain serviceable for many years. Under unfavorable conditions, explosives and ammunition which are deteriorating pick up heat so fast that it cannot be dissipated, and the explosives and ammunition may burst into flames as a result. An explosion or detonation may also result when deteriorating explosive or ammunition is confined too closely. A definite safety hazard results when repacking, renovation, and salvage operations are not property supervised and conducted in accordance with recognized standards.
Magnesium is a fairly strong, silvery-white, light-weight metal (one third lighter than aluminium) that slightly tarnishes when exposed to air. In a powder, this metal heats and ignites when exposed to moisture and burns with a white flame. It is difficult to ignite in bulk, though it is easy to light if it is shaved into thin strips. Once ignited, it is difficult to extinguish, being able to burn in both nitrogen (forming magnesium nitride), and carbon dioxide.
Among the more common sources of fire hazards are excessive quantities of powder and loose explosives, accumulation of wastepaper, broken boxes, unauthorized use of spark-producing tools, defective machinery, faulty electrical equipment, and failure to provide the proper barricades and firebreaks necessary to prevent the spread of fire from one operation to another.
Lack of training and violations of instructions or written regulations are frequently responsible for serious consequences. The most common violations include smoking, carrying matches in forbidden areas or buildings, and tampering with explosives or ammunition, particular, ly grenades or fuzes.
Failure to understand and carefully observe the safety precautions prescribed for destroying ammunition and explosives might cause grass fires or explode nearby ammunition piles which are awaiting destruction. The most frequent sauce of these troubles is flying fragments released upon detonation.
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