Next time you step onto the beach, bend down, grab a handful of sand and admire the fact: By mass 47% of what you hold in your hand is the element silicon. The rest is simply oxygen. Remarkable!
Silicon is the second most abundant element in the earth’s crust (27.7%) – only oxygen beats it – and can easily be extracted from white sand (SiO2) in a spectacular reaction in the school science laboratory.
In Thermite reactions metal oxides react with aluminum to produce the molten metal. These redox reactions require substantial activation energy to get going and are highly exothermic.
They have been used industrially for welding (even under water), the preparation of metals from their oxides (reduction) and the production of incendiary devices. The process is initiated by heat but then becomes self-sustaining. Read the rest of this entry »