Aluminium, -extraction

Aluminium Extraction with trifluoro-acetyl acetone in toluene Analysis of toluene extract by GC 6 pg A1 in 2 xl extract [18]... 

Aluminium Extraction of pyrocatechol violet complex with chloroform Spectrophotometry at 590 nm < 0.1 xg/l [26]... 

Normally electrode reactions take place in solutions, or sometimes in molten salts (e.g. aluminium extraction). In order to minimize the phenomenon of migration of the electroactive ions caused by the electric field (Chapter 2) and to confine the interfacial potential difference to the distance of closest approach of solvated ions to the electrode (Chapter 3), the addition of a solution containing a high concentration of inert electrolyte, called supporting electrolyte, is necessary. This has a concentration at least 100 times that of the electroactive species and is the principal source of electrically conducting ionic species. The concentration of supporting electrolyte varies normally between 0.01m and 1.0 m, the concentration of electroactive species being 5 mM or less. The... 

Fig. 15.4. Scheme of a cell for aluminium extraction by the Hall-Heroult... 

Due to the increasing cost of energy, the need to preserve the environment, and the non-existence or exhaustion of suitable natural raw materials in some areas, industrial and other waste materials are of interest as possible raw materials or supplementary fuels or both. Energy can be saved if even a part of the CaO can be provided by a material, such as blastfurnace slag, that does not require decarbonation. Supplementary fuels include such materials as used or reject tyres and pulverized household refuse, which can be introduced into the system in various ways. Some materials, such as pulverized fuel ash (pfa fly ash) can serve as raw materials that also possess some fuel content. Other wastes that have been used include calcium silicate residues from aluminium extraction, mining residues, and precipitated calcium carbonate from various industries. 

Charles Hall, in the USA, found a way of extracting aluminium cheaply enough to enable it to be widely used. Why are aluminium extraction plants often found in regions where there are mountains and lots of running water and cheap hydro-electricity Write out the possible process taking place. 

In the case of AHFS treated samples high levels of crystallinity were maintained at the expense of lower levels of aluminium removal. From Tables 2 and 3 it is seen that the rate of AHFS addition does not affect the product Si/Al ratio or crystallinity. The greatest influence appears to be reaction time and the concentration of the AHFS solution, in agreement with the work of Garraldn et al [14]. Overall, treatment by AHFS appears to be an optimisation process between crystallinity and aluminium extraction. Controlling the experimental parameters in... 

The crystallinity of the dealuminated samples is listed in Tablel. It was observed that H-Y(di6 / ), H-Y(d32%) and H-Y(d5o%) retained high degrees of crystallinity [11], However, a noticeable crystallographic degradation was noted for H-Y(d64%) sample since the crystallinity decreased to 40% as a result of the massive aluminium extraction [12]. 

Hughes, J. C. (1982). High gradient separation of some soil clays from Nigeria, Brazil and Columbia. I. The interrelationships between iron and aluminium extracted by acid ammonium oxalate and carbon. /. Soil Sci. 33, 509-519. 

Figure 4.3 Cell for aluminium extraction by the Alcoa chloride process.

The RSC-produced ro)cctAlchemy comprises downloadable material covering 15 major topics, including aluminium extraction and copper refining ... 

Caustic soda has similar outlets to chlorine and these are shown in Figure 10.3. Large amounts are used in the organic and inorganic chemicals industries, for soaps and detergents, and for aluminium extraction. 

Fig. Al Steps in the Hall-Heroult process for aluminium extraction.

Natural calcium sulphates occur in abundant deposits throughout the Mediterranean basin. Manufacture of these materials was mainly as the by-product of the aluminium extraction industry (see Heaton, 1928 and the entry for calcium sulfate, anhydrite type, above). 

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