Aluminum Extractor/Research Development
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Aluminum extraction from clay - we are not talking about energy intensive smelting (requires fuel consumption on the order of 1 gallon of fuel oil for 1 kg of metal) with bauxite as aluminum ore, but a thermal and chemical process based on clay- not bauxite. Aluminum is not smelted, but leached out with hydrochloric acid: http://www.freepatentsonline.com/4388280.html. This is remarkable news to anyone interested in a better world - formerly strategic metals can be made anywhere. I need not emphasize the ranges of use of aluminum.
Kaolin clay is composed of aluminum and silicon (Si2Al2O5(OH)4). Reduction of Kaolin would then result in an aluminum/silicon alloy. In practice, carbides (usually SiC) resist further reduction except at very high temperatures (2050°C). Thus, the smelted product is likely some aluminum-rich alloy with various highly refractory simple and complex carbides.
This process may extract aluminum compounds from clay without the high-temperature "calcining" pre-process.
Parent material is reduced carbothermically, that is, it is reduced in the presence of carbon and the absence of oxygen at high temperatures. The carbon is oxidized to produce carbon mon- and di-oxide and the metal oxides are reduced.
The paper carbothermal reduction of alumina by m.halmann (at) weizmann.ac.il describes the carbothermic reduction of alumina rich material in an atmosphere of methane gas at high temperatures. Internal copy of this paper: File:Halman.pdf
Such temperatures could be produced with a point focusing solar collector (see Metal Refining for more)
Page 66 in this online book talks about a plant in the Ukraine that smelts kaolin into an aluminum/silicon alloy: The Handbook of Aluminum by George E Totten, D Scott MacKenzie
At temperatures below 2000°C, I assume aluminum metal may be separated from silicon carbide (SiC).
Low-temperature electrolytic refining (speculative): see Metal_Refining#Electrolysis
Papers and Patents
- Good process overview - 
- 1980 patent for leaching aluminum from clay - 
- USA sourcing of alumina from clay by HCl leaching - 
- HCl leaches alumina with 70% efficiency from clays - 
all about aluminium: http://sam.davyson.com/as/physics/aluminium/siteus/index.html
aluminum production from clay (& other non-bauxite materials): http://books.google.com/books?id=d8VUAAAAYAAJ&pg=SL3-PA38#v=onepage&q&f=false
aluminum recycling and processing for sustainability http://books.google.at/books?id=t-Jg-i0XlpcC&pg=PA197&lpg=PA197&dq=intitle:aluminum+production+clays+-patent&source=bl&ots=dyGaESjSJu&sig=uhSUFo2Bc9UYzCGMKFII7OmpqF8&hl=de&ei=Cr9hSt79O5qOnAONxKz4Dw&sa=X&oi=book_result&ct=result&resnum=3
environmental chemistry of aluminum http://books.google.at/books?id=lNxltQeVP9UC&pg=PA253&lpg=PA253&dq=intitle:aluminum+production+clays+-patent&source=bl&ots=7Akaax7fNZ&sig=Q6v9n37jOf_FEDAjaN4aaqpSJZY&hl=de&ei=Cr9hSt79O5qOnAONxKz4Dw&sa=X&oi=book_result&ct=result&resnum=6
environmental guidelines for aluminum manufactoring http://www.miga.org/documents/AluminumManufacturing.pdf & http://www.ifc.org/ifcext/enviro.nsf/AttachmentsByTitle/gui_alummfg_WB/$FILE/alum_PPAH.pdf (world bank and investment guarantee agency)
pollution prevention in manufactoring aluminunm http://www.p2pays.org/ref/21/20400.htm
why aluminum smelting is not good http://planet.wwu.edu/archives/2006/articles/fall/popping-the-top.php
national environmental health report on aluminium http://enhealth.nphp.gov.au/council/pubs/pdf/alumin.pdf
Handbook of corrosion engeneering http://www.scribd.com/doc/9402306/Handbook-of-Corrosion-Engineering-
extraction of aluminum http://www.tms.org/pubs/Books/4062.chapter2.pdf
the evolution of the world aluminum industry http://books.google.at/books?hl=de&lr=&id=1NS2ja36QckC&oi=fnd&pg=PA39&dq=aluminum+production+from+clays&ots=dQn5uYR_vZ&sig=Afp24-4CYgPIkWPhM0UjSF-4iXw
aluminum alloy castings http://books.google.at/books?id=JM0u1vwrS5UC&pg=PA21&lpg=PA21&dq=intitle:aluminum+production+clays+-patent&source=bl&ots=VwQAbCkL-o&sig=vMXAQovuSJOIYroY8VfQJYFfKE4&hl=de&ei=Cr9hSt79O5qOnAONxKz4Dw&sa=X&oi=book_result&ct=result&resnum=9
article: hydrolysis products of solution and exchangeable aluminum in acidic soil http://scholar.google.at/scholar?q=info:VxZNUwsol1IJ:scholar.google.com/&output=viewport&pg=1&hl=de