Aluminium (bauxite) electrolysis
This website shall welcome you into the most deepest of scientific theories, ideas and extraction methods of Aluminium and its relevance to electrolysis and the reactivity series. Welcome to Andy Taleb's website, i hope you enjoy! (if a word is misheard during a video the information/script is above each video)


Electrolysis (The Hall-Héroult version for Aluminium) is the process of decomposing a solution or a molten compound by passing an electric current through it. Electrolysis is used to refine and extract highly reactive metals which are on the top of the reactivity series such as potassium, sodium, calcium or magnesium from their ores. Electrolysis involves the use of electroplating which is the use of electrolysis to coat a metallic object with a thin layer of another metal via electric current through sulphuric acid. The Anode which is the positively charged metal is what coats a cathode with a thin layer of oxide for protection against corrosion and rust. This works by the positive anode losing its ion layer to the cathode therefore gaining an extra metal sheet layer.

The metal Aluminium is the most abundant metal in the Earth's crust, has an atomic number of 13 and is a shiny white metal that holds many advantageous characteristics. It is light, nontoxic, nonmagnetic and does not rust or corrode (due to its oxide layer of protection). The ore Bauxite which aluminium is mined from contains many other impurities such as iron, clay, silt and silica. Due to this Aluminium isn't found in nature as a pure element. It displays a high chemical reactivity, which means it tends to bond with other elements to form compounds or in this case a bauxite ore. The chemical formula for aluminium oxide is Al2O3, therefore to get to aluminium from the ore it must take specific steps specifically refining through electrolysis. The reason Electrolysis is used is because of Aluminium’s high reactivity as indicated on the reactivity series (and since it is just above carbon which is why it needs electrolysis), therefore rendering it difficult to extract without mass amounts of energy.

This video shall explain the information at the top in a more engaging manor. 

Aluminium is mined from the ore bauxite which is purified by the Bayer Process to receive alumina. Alumina is a white powdered version of aluminium which is still in use today for cutting tools and purifying water. To get to alumina the bauxite ore must be first mixed with a hot concentrated solution of NaOH. The NaOH will dissolve the oxides of aluminium and silicon but no other impurities such as iron oxides, which remains insoluble. The insoluble materials are removed by efficiently cheap methods to produces alumina which contains 52.9% aluminium and 47.1% oxygen. To reach aluminium the Hall-Héroult process should be taken.

The Hall-Héroult process which uses electrolysis at its full potential would then decompose the alumina into aluminium which also puts it back from its powder to metal form. Before electrolysis alumina must be processed through the crushing and grinding with sodium hydroxide at high temperature and pressure. Then digested and settled for 30 minutes at 145 °Celsius. Then Precipitation and calcination in other words drying. The traditional setup for Alumina-Aluminium electrolysis requires an iron cathode (negative) and a carbon anode (positive). This is topped off with a CO2 layer and surrounded by molten cyrolite Na3 AIF6 and AL2O2 in order to keep the reaction at a pace. 

According to science focus 4 (figure 2.2.3 pg 30) bauxite is mined in Australia mainly in Portland Victoria, Pera Head Queensland and Worsley Western Australia.

Transportation: In addition to auto parts, motorcycles and airplane parts increasingly are made of aluminium, as are license plates.

Building and construction: Siding, roofing, gutters, window frames, hardware, paint are made from aluminium. 

Packaging: This includes aluminium foil and trays, gum and candy wrappers. In 2009, packaging beat out the transportation industry as the top use of aluminium

At current consumption rates (190 million tonnes of aluminium per year is mined and used), deposits shall last up to an estimated 131 years from June 2008. Therefore if no other reserves are discovered in the world then aluminium resources shall be exhausted by 2139. However in Australia around an estimate of 63-80 million tonnes of aluminum is exhausted per year. Therefore we will run out around 2090. The main solution includes the recycling of all aluminium products, according to http://aluminium.org.au/recycling Aluminium is 100% recyclable and experiences no loss of properties or quality during the recycling process. Therefore increasing aluminium trading/recycling prices to help encourage aluminum collectors to gather more aluminium for recycling may bring an end to our worries that is if we do not destroy them entirely.

This is additional information in order for the reader to further understand extraction and decomposition of aluminum process.

Remember: Two tons of alumina are required to make one ton of aluminum.
Four tons of bauxite are required to produce 2 tons of alumina.

The difference between hall Héroult and Bayern process:The Hall–Héroult process is the major industrial process for smelting Aluminium. It involves dissolving alumina in molten cyrolite, through electrolysis. Prior to the Hall–Héroult process, aluminium was made by heating bauxite ore along with sodium or potassium in a vacuum. This method was complicated and used up many materials that were in themselves expensive at that time. This meant the cost to produce the small amount of aluminium made in the early 19th century was very high, higher than for gold or platinum. (did not explain in detail because this is not my entire focus)

The Hall–Héroult process was invented in 1886 by the American chemist names Charles martin hall. It was targeted at changing alumina (what seemed to be a near useless metal) into a metal that would be cheap, efficient and withstand human overconsumption over mass amounts of time. (did not explain in detail because this is not my entire focus)

The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide). The process began to gain importance in metallurgy together with the invention of the hall Héroult electrolytic process invented just one year earlier in 1886. Today, the process is unchanged and it produces nearly all the world's alumina supply a step in aluminium production. (did not explain in detail because this is not my entire focus)

Total video time: 3:09
bibliography:
Science text book (science focus 4) Kerry. Whalley, Carol Neville, Peter Roberson, Greg Rickard, Geoffrey Philips, Faye Reffrey and Janette Ellis. Made: Unknown. 

http://curiosity.discovery.com/question/what-is-alumina (Author: Curiosity.com, Date updated and/ made: Uknown.

http://terresacree.org/aluminiumanglais.htm (Author: Terrescree Date updated and/ made: Unknown.

http://www.roperld.com/science/minerals/bauxite.htm (Author: Ropeworld Date updated and/ made: 22 march 2014

http://science.howstuffworks.com/aluminum3.htm (Author: Harris, William, "How Aluminum Works"  Date updated and/ made: 29 September 2008.  

CDC - NIOSH Pocket Guide to Chemical Hazards – Aluminium (Author: NIOSH Pocket Guide, Date updated and/ made: Unknown

http://www.world-aluminium.org/statistics/ (Author: World Aluminium Date updated and/ made: Unknown 

http://education.jlab.org/itselemental/ele013.html (Author: Jefferson Lab, Date updated and/ made: Unknown 

http://www.world-aluminium.org/production/refining/chemistry.html/ (Author: Aluminium chemistry,  Date updated and/ made: Unknown

http://www.rocksandminerals.com/aluminum/process.htm (Author: Rocks and Minerals, Date updated and/ made: 05/16/99 (from site) VERY IMPORTANT SITE.

http://www.d.umn.edu/~pmorton/geol2350/2007/powerpoints/chemistry.html (Author: World Aluminium, Date updated and/ made: 2000 (rest unknown)

http://bauxite.world-aluminium.org/refining/process.html (Author: Aluminum for future generations, Date updated and/ made: 2010 (rest unknown)