Termites - composition and preparation
Word termite is usually a mixture of powdered metal and oxide. Leaving aside some exotic metals, such as reducing component is suitable for aluminum. A typical example is a mixture of aluminum and iron oxide (reaction temperature about 1500 ° C). The reaction is strongly exothermic (heat is released), and when it occurs in a reduction of the corresponding metal oxide and the oxidation of the reducing metal oxide. The amount of energy released depends on the flue temp substances (hence the reaction enthalpy). The higher the reaction enthalpy smaller (more negative) by the reaction exotermnější. Ignition termitových lodge is quite difficult and is used to magnesium ribbon together with a mixture of Mg 2 + BaO (I use a bigger firecracker firecracker and light up with her ??and termite (Fe 2 O 3 + Al).
The composition of these termites is calculated according to the stoichiometry of the reaction.
The following mixture react violently, sometimes explosively, and therefore not suitable for the preparation of metal, but as impressive spectacle.
Classic thermite Al + Fe 2 O 3
Ignites a mixture of BaO 2 + and Mg magnesium ribbon.
A mixture of Zn + Pb 3 O 4
Zinc has a smaller heat of combustion, but the reaction is due to low enthalpy merge red lead is sufficiently exothermic.
A mixture of MnO 2 + Al
The reaction proceeds very rapidly, thus not suitable for the preparation of manganese metal.