ALUMINIUM – MATERIAL OF FUTURE
“WITH ALUMINIUM WE CO-CREATE THE FUTURE”
PRODUCTION OF ALUMINIUM
“LUCRATIVENESS WITHIN INNOVATION AND AMBITION”
WAYS OF USING ALUMINIUM
“TOGETHER WE CAN MANAGE ALMOST EVERYTHING”
A name aluminium is derived from a word alumen, which was known already in an antique period as a compound alum, colourless salt of potassium aluminium sulphate. There are many minerals with aluminium in the Earth’s crust; the most frequent are feldspars and spars. Aluminium in a natural form is the third most frequent element on the Earth, immediately after oxygen and silicon.
According to the legend already in the antique Rome, there was one goldsmith, who made a plate of a light, silver like metal and bestowed it to the emperor Tiberius, and stressed his achievement of producing the metal from an ordinary clay. The emperor got scared that his gold and silver would lose its value with this metal and he had the goldsmith executed. Could that metal be aluminium?
The known history of aluminium begins with Hans Christian Ørsted, who was the first to produce impure aluminium by reduction of aluminium chloride with potassium. Friedrich Wöhler was the first to produce pure aluminium with the same reaction two years later.
Nowadays a technological procedure basis on the electrolysis of melt NaCl/AlCL3. In industry, aluminium is produced with the electrolysis of aluminium oxide, which is prepared from bauxite. Wet (Bayer’s) and dry (Le Chatelier’s) procedures are used.
Aluminium is the material with theoretically never-ending life expectancy, it is easy to maintain, it is efficient thermal insulator and it meets high hygienic standards. It is not a problem when it is exposed to extreme weather conditions, its characteristics do not change during its use, it is stainless, resistant to UV rays, it does not change its colour or structure and it does not have natural pests. In the environment, it naturally becomes oxidised, yet this layer only additionally improves its surface solidity. It is the only metal, which also after protection of the surface keeps its natural colour. With an electrochemical procedure of anodising (anodize) there is created a thin layer of oxide on the surface, which increases the solidity and abrasive resistance, and the resistance to salt and polluted air.
We produce aluminium with the electrochemical process in electrolytic cells, where alumina (Al2O3) is decomposed into its components: aluminium and oxygen. The process proceeds in solution of an electrolyte, which main substance is cryolite (Na3AlF6), at the temperature between 950 and 970 degrees Celsius.
For this process, we need direct current, which flows through the electrolytic cell from an anode to a cathode, wherein alumina is decomposed. Liquid aluminium accumulates on the cathode in a cathode trough, wherein the quantity of the produced aluminium depends on a size of the cell, respectively on the current intensity. When the liquid aluminium in the cathode reaches certain height, it is pumped into special pots. In these pots, it is taken to the foundry as raw material for a further treatment.
Aluminium never turns into waste
In comparison with the first production, only five percent of that energy is used to recycle the aluminium. The first production is expensive and energy consuming, but once the aluminium starts its life cycle, it does not get out of it anymore. Therefore, aluminium is considered as green metal since all of it being ever produced can be repeatedly used for centuries and it never turns into waste.
Although aluminium has been produced for just over one century, and intensively only after World War II, there is no area existing anymore, where it would not be used. Due to its remarkable characteristics, its extent of use is still increasing, also in the areas reserved for classic materials with longer tradition.
We meet aluminium on every step we take – when we sit in a car or in a plane, when we drink beer, roast a chicken, when we look through a window.
Due to its lightness, corrosive resistance, good mechanical characteristics, excellent forming abilities and conductivity, it represents the metal, which reaches the highest level of consumption among all of the metals. More and more it is built into automobiles – there is already around 135 kilograms of aluminium in an average European car. Beside the automobile industry, it is also used in construction industry, in general machine manufacture, for packaging production, in refrigerators, in heating pumps and many more.