The aluminothermy

The aluminothermy was discovered by N.N. Beketov in 1859. As a method of producing iron, manganese, chromium, tungsten, vanadium, rubidium, lithium, calcium, barium, aluminothermy is of great practical importance. It is also used to produce some alloys, for welding rails.

The aluminothermy was discovered by N. N. Beketov in 1859

In the school laboratory, aluminothermy can be reproduced by applying the electric arc of Petrov, while not forgetting about safety techniques. A term is a mixture of ferrous oxide and iron powder with aluminum powder.

When the mixture is ignited, the reaction begins:

3Fe3O4 + 8l = 4l2O3 + 9Fe + 795 .

The reaction is exothermic, passes with the release of heat. A temperature of about 35000 C develops. Therefore, experience must be carefully prepared.

First, prepare a pound 5-6 cm high and 3-4 cm in diameter from the asbestos board. Put a small piece of asbestos on its bottom so that the termite does not spill out and fix the pound in the ring of the metal tripod. The tripod should be placed on a table or on an iron baking tray of large size and cover the baking sheet with the bottom of the tripod with dry sand.

Then prepare two electrodes. One is made of a strip of metal 6-8 cm long and 0,4-0,6 cm wide. The lower end of the strip is slightly curved and insert the electrode with this curved end into the pound almost to the bottom; Tin while this should be adjacent to one of its walls. The upper end of the electrode must also be bent and attached to it one cord from the electrical wire.

The second electrode, take the finished - a graphite rod about 20-25 cm long and 0,9-1,0 cm in diameter. At one end of the coal round make a small groove and secure the second end of the electrical wire in it. For insulation, fix the carbon electrode in a wooden tube holder.

Now pour 15-20 g of termite into the asbestos pound and attach the slide rheostat.

When carrying out the experiment, wear safety glasses.

Everything is ready for the experience. Turn on the electric current and dip the graphite electrode into the pound with termite (if necessary, adjust the start of the process with the rheostat). Thanks to the contact, an electric arc will immediately arise. As soon as the aluminothermy reaction starts, remove the carbon electrode and put it in the sand. Turn off the current.

The aluminothermy flows very violently, and the molten iron recovers on the sand.

The aluminothermy can be used to produce other metals and their alloys. To do this, we must take the oxide of the corresponding metal (or metal oxides if we want to obtain alloys) and aluminum powder. The weight quantities of the starting materials must be calculated from the reaction equation.

The aluminothermy is well used for the restoration of the following oxides: iron, nickel, manganese oxide, tungsten and vanadium anhydrides.