Hall-Héroult+process

who discovered/developed this processes? - The American chemist Charles Martin Hall and the French chemist Paul Heroult.
 * How did they come across this?
 * At the time aluminum was considered a precious metal that is used in fine jewelry. As time went on, people began to see the more industrious uses of aluminum and started to use it for bigger things such as making automobiles and airplanes lighter. But the problem with aluminum was that it took a long time to extract and produce pure aluminum. Charles Martin Hall invented an inexpensive method for the production of aluminum eight months after graduating from college. He produced globules of aluminum metal by the electrolysis of aluminum oxide dissolved in a cryolite-aluminum fluoride mixture. In other words, he dissolved alumina in molten cryolite and electrolyzed the solution to make pure aluminum.



http://ibchem.com/IB/ibfiles/options/opt_E/ope_img/hall.jpg
 * As for Heroult, he spent hours reading Science, and particularly, research and discovery. His interest reaches its highest point the day he comes upon the famous work of Sainte-Claire Deville, with the unglamorous title, "Aluminum, its properties, its production and applications". He joined the prestigious École des Mines and drew sketch after sketch of his assumptions. Soon he started experimenting on electrolysis and soon electrolytic aluminum was born.



http://z.about.com/d/chemistry/1/0/t/r/PaulHeroult.jpg

What does this process produce? Aluminum


 * Why is the production of the product necessary?
 * Aluminum is the most produced non-ferrous metal in the world because of its many qualities. Aluminum is ductile, resists corrosion, abundant, and is very light. All these qualities make aluminum unique and very important in today’s many industries.
 * What is the product used for?
 * Corrosion resistant
 * Effective in electrical lines
 * Kitchen ware and water and air tight food wrapping
 * Transportation: airplanes, trains, cars, and many more are made lighter with the use of aluminum as sheets, tubes, and castings.


 * What is used (reactants) in the production of this product? -
 * Al2O3 + C (molten alumina and Carbon) are the reactants of the production of the product.
 * Include detail
 * The electrolyte consists of molten alumina, Al2O3, and because the melting point of alumina is 2051 degrees Celsius, a flux is used to lower its melting point. The cryolite flux, Na3AlF6, is not consumed and so does not appear on the process equation. The molten aluminum produced by the process serves as the cathode. Since aluminum is denser than alumina, it sinks to the bottom of the reactor as a separate liquid phase. The carbon anode is consumed in the process, yielding carbon dioxide gas.
 * Make sure to include the balanced reaction equation.
 * 2Al2O3 + 3C --> 4Al + 3CO2

Where in industry is this process used? - Aluminum is used in just about every aspect of a community. The major parts of industry that aluminum is used extensively are in transportation, packaging, and construction. And because aluminum is used in massive amounts, this process is used in just about every industry that requires aluminum to produce their products. For example: transportation, food packaging, and construction.
 * Are there any other processes that can be used?
 * There are no other processes to produce Aluminum, but there are multiple ways to produce the starting chemical Alumina
 * There was a process pioneered by Hans Christian Oersted that was able to produce impure aluminum, but the Hall Heroult process is the only known process that can produce pure aluminum
 * Oersted's approach worked to refine aluminum chloride by adding potassium amalgam in a double displacement reaction producing aluminum amalgam, Then the mercury was distilled from the amalgam leaving a somewhat impure aluminum metal.
 * Which process is more efficient? Why?
 * This process is the most efficient because it is the only known process that can produce pure Aluminum and it can be in theory be improved to be 99.99% efficient.

When was this process first discovered? It was first discovered in 1886 simultaniously by Martain Hall in the United States and by Paul L. T. Heroult in France.


 * Has it been refined/modified with the advances in technology/science?
 * yes it has, the original catalyst of the reaction Cryolite was replaced by a more effective and efficient mixture of aluminum, calcium, sodium fluorides.
 * When did it become used in the industrial setting?
 * It became used in 1886 and was since used to increase the amount of Aluminum produced exponentially

Why is the process used in industry? - The process is used in industry because aluminum is an extremely valuable metal and the modified Hall Heroult Process is still the most efficient and cost effective way to produce Aluminum.


 * Are their any special requirements/certification/permits needed in order to carry out this process?
 * No
 * Are all employees specially trained to supervise this process?
 * Yes

How does the process work? - The process works by using a cryolite solution and then running and electrical current through the solution. Then just siphon off the now separated aluminum.

http://ibchem.com/IB/ibfiles/options/opt_E/ope_img/cell.jpg


 * What are the steps/stages?
 * First the Aluminum Oxide must be extracted from the Bauxite
 * the alumina (Aluminum Oxide) is dissolved in a bath of molten cryolite within a large carbon or graphite lined steel container.
 * Then an electrical current is run through the solution between a positive anode and the negative cathode (The carbon or graphite lined pot)
 * Then molten aluminum falls to the bottom of the pot and is siphoned off.




 * What are the necessary requirements for the process to achieve the final products?
 * The starting reactant must be alumina (Aluminum Oxide)
 * Large Electrical Currents
 * Carbon/Graphite lined container
 * Are there any wastes or by-products which are hazardous?
 * The only dangerous by-products are Carbon Dioxide and Carbon Monoxide in gaseous form.
 * Is this a large scale application process or smaller scale process?
 * This is a large scale application because after the main batch of alumina is completely used up, it can then be replenished and the process continues.

http://img.alibaba.com/photo/11958045/Aluminum_Ingot.jpg


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__**Bibliography**__

Works Cited “Caveman Chemistry.” //www.cavemanchemistry.com/////cavebook/////chchloralkali2.html//. Kevin M. Dunn., 2009. Web. 21 Mar. 2010. . ‌‌

“Hall-Héroult process.” //www.chemistrydaily.com/////chemistry/////Hall-Heroult_process//. Chemistry Daily, 4 Jan. 2007. Web. 21 Mar. 2010. . ‌‌

“How Aluminum is Produced.” //www.rocksandminerals.com/////aluminum/////process.htm//. Reynolds Aluminum, Alcoa Aluminum and the Aluminum Institute., 1999. Web. 21 Mar. 2010. . ‌‌

“Paul Louis Toussaint Héroult (1863 - 1914).” //www.corrosion-doctors.org/////Biographies/////HeroultBio.htm//. Corrosion Doctors, 2010. Web. 21 Mar. 2010. . ‌‌

// Facts On File Online Databases //. Web. 20 Mar. 2010. .

"Science Online." // Facts On File Online Databases //. Web. 20 Mar. 2010. .

"Student Resource Center Gold Logout." // GaleNet //. Web. 20 Mar. 2010. <http://find.galegroup.com/srcx/retrieve.do?subjectParam=Locale%2528en%252C%252C%2529%253AFQE%253D%2528su%252CNone%252C8%2529 Aluminum%2524&contentSet=GSRC&sort=Relevance&tabID=T001&sgCurrentPosition=0&subjectAction= DISPLAY_SUBJECTS&prodId=SRC 1&searchId=R1&currentPosition=1&userGroupName=king46652& resultListType=RESULT_LIST&sg HitCountType=None&qrySerId=Locale%28en%2C%2C%29%3AFQE %3D%28SU%2CNone%2C8% 29Aluminum%24&inPS=true&searchType=BasicSearchForm& displaySubject=&docId=EJ2644040078& docType=GSRC>.