Thursday, December 20, 2007
Friday, December 14, 2007
Thermite
Thermite reactions have many uses. Thermite was originally used for repair welding in-place thick steel sections such as locomotive axle-frames where the repair can take place without removing the part from its installed location. It can also be used for quickly cutting or welding steel such as rail tracks, without requiring complex or heavy equipment.
A thermite reaction, when used to purify the ores of some metals, is called the Thermite process, or aluminothermic reaction. An adaptation of the reaction, used to obtain pure uranium, was developed as part of the Manhattan Project at Ames Laboratory under the direction of Frank Spedding. It is sometimes called the Ames process.
When thermite is made using iron (II) oxide, for maximum efficiency it should contain, by mass, 25.3% aluminium and 74.7% iron oxide. (This mixture is sold under the brand name Thermit as a heat source for welding.) The complete formula for the reaction using iron (III) oxide is as follows:
ΔH = -851.5 kJ/mol[citation needed]
When thermite is made using iron (II,III) oxide, for maximum efficiency it should contain, by mass, 23.7% aluminium and 76.3% iron oxide. The formula for the reaction using iron (II,III) oxide:
ΔH = -3347.6 kJ/mol[citation needed]
Interestingly, a modified version of this process (run under an inert atmosphere) can be used to produce a number of alloys—the mixture is usually ignited electrically. This approach has been used to prepare Ni-Al Alloys amongst others.
Copper thermite, under trade name CADWeld, is used for welding together thick copper wires for the purpose of electrical connections.
1 gram Aluminum (400 mesh)
2 grams Iron Oxide (Rust)
A couple of inches of a strip of Magnesium
1. Measure
2. Mix well
3. Use magnesium as ignightor
4. Use torch to light magnesium
http://en.wikipedia.org/wiki/Thermite
http://en.wikipedia.org/wiki/Iron_oxide ( This can be made by burning fine steel wool and forcing air through it until it is totally consumed. The sooty remains are Black Iron Oxide.. )
Labels: Thermite