Aluminothermic reaction

The alumino is an applied in laboratory and process technology for the production of metallic elements E of the corresponding oxides by the reaction of EO with elemental aluminum in accordance with the following equation:

The method was first held in 1894 by Hans Goldschmidt, and is therefore often referred to as Gold Schmidt method. The aluminothermy (often also called simplistic " Alumothermie " ) makes use of the very high affinity of aluminum to oxygen advantage, which is the real driving force of the reaction:

The aluminothermal reaction is highly exothermic, which reached temperatures are places to 2450 ° C, so that the entire reaction mixture is present as a melt. Nevertheless, the reaction initiation by an " ignition pellet " needs (usually a mixture of magnesium and barium peroxide ). In modified versions of the reaction (especially in the extraction of boron and silicon ) elemental sulfur is added in addition. After the reaction, the recovered ( semi) metal can be broken out in the form of Regulus from the slag.

In this way, among other things, the elements iron (Fe ) in the thermite process, but also chromium (Cr), manganese (Mn ), titanium ( Ti), zirconium (Zr ), boron (B) and silicon (Si ) can be prepared. As a by-product of alumina.

Industrially finds the aluminothermy used where the cheaper reduction by carbon is not possible ( eg due to carbide formation as a side reaction ), such as in the extraction of chromium on nichtelektrolytischem ways.