Making Aluminium Metal | pengecoran aluminium

Aluminum is a metal in the world . This metal is 8 % of the earth's crust part . Aluminum metal was first made in pure form by Oersted , in 1825 , by heating ammonium chloride with potassium amalgam mercury . In 1854 , Henri Sainte Claire Deville and make aluminum from aluminum sodium chloride by means of heating with metallic sodium . In 1886 , Charles Hall began producing aluminum with large -scale processes such as now , namely through the electrolysis of alumina dissolved in cryolite . In the same year Paul Herault France gets patent for a process similar to the Hall .( membuat cetakan aluminium )
pengecoran aluminium
pengecoran aluminium
The combination of the properties of light and strong , made ​​of aluminum suitable for a variety of uses . With the same weight , aluminum has two times better conductivity than copper , and tenacity ( ductility ) is high at high temperatures . Ordinary aluminum combined with metals such as copper , magnesium , zinc , silicon , chromium , and manganese so the usefulness even more. Metal aluminum or its alloys ( alloy ) , especially with magnesium alloys , widely used in aircraft structures , cars , trucks , and railroad cars , etc. . When used properly , corrosion -resistant aluminum .
Aluminum metal made ​​through electrolytic reduction of pure alumina ( Al2O3 ) in the melting cryolite bath . Alumina can not be reduced by carbon , due to the formation of Al4C3 ( aluminum carbide ) , and the reverse reaction between aluminum vapor with CO2 in the condenser will lead to the formation of aluminum oxide as the original . Enthalpy changes that occur in the reaction is as follows :
Al2O3 + 1.5 C - > 2AL + 1.5 CO2
Required for the reduction of carbon derived from the anode and it is necessary to between 0.5 to 0.6 kg of carbon per kilogram of metal . Although theoretically necessary is actually just 0.33 kg , but because of the carbon dioxide that comes out it contains 10 % to 15 % carbon monoxide ( CO ) , the amount required in practice is certainly greater . Steps in the production of aluminum metal is as follows .
1 . Install or replace the cells lining
2 . Create and use a carbon anode in the cell
3 . Prepares cryolite bath and composition control
4 . Dissolve alumina dissolved in cryolite
5 . Electrolyzed solution of alumina to form aluminum metal acts as a cathode .
6 . Carbon electrode was oxidized by oxygen released
7 . Aluminum liquid flow out of the cell , combined ( if necessary ) , molded into the metal bars and cooled .
Cell electrolyte big steel box-shaped . In it there is a cathode compartment are coated with a mixture of pitch and anthracite coal or coke that is baked on the premises with the help of electric current , or the cathode blocks that have been baked and then cemented to each other . The cathode compartment hole has a depth of 30 to 50 cm , with a width of approximately 3 m and a length of 9 m depends on the cell type and the planned load . Coating thickness ranging from 15 to 25 cm on the sides and 26 to 46 cm at the base . Among the steel wall mounted thermal insulation and coatings consisting of heat-resistant steel , asbestos block , or other materials .( pengecoran aluminium )
Coatings mounted on the bottom of a large steel bar that serves as a cathode current collector . This rod sticking out through a hole in a steel box and connected to the cathode introductory bars . Cells resistant coatings usually 2 to 4 years . Damage usually occurs due to infiltration through the cathode metal that dissolves or because of the penetration of the metal out of the steel box through leaks around the collector current. Overall coatings , insulation and collector was then replaced . Resurfacing cell box is a large part of the cost of production and are here included not only labor , collector , coatings and insulation materials , but also the loss of electrolyte material is absorbed by the coating used. Picture schematic cross section of an aluminum reduction bath is shown as the following picture ( image source : http://www.substech.com/ )

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