Aluminum water

Figure 8.3 General wastage of an aluminum water manifold from a diesel engine cooling system. Note the generally wasted internal surface due to concentrated caustic and the presence of white deposits and corrosion products.

The system aluminum/water belongs to group II where represents the pitting potential and lies between -0.8 and -1.0 V according to the material and the medium [22,23,36,39,42]. Since alkali ions are necessary as opposite ions to the OH ions in alkalization, the resistance increases with a decrease in alkali ion concentration (see Fig. 2-11). In principle, however, active aluminum cannot be protected cathodically [see the explanation of Eq. (2-56)]. 

Experimental test results for molten aluminum-water RPTs are described in Section V. Also shown is a tabulation of most documented aluminum-water explosive boiling incidents (see Table XIV). In many accidents, the quantity of water was quite small, e.g., some resulted when wet aluminum ingots were loaded into melting furnaces containing molten aluminum. In contrast, one notes that few, if any, serious events have ever been obtained when small quantities of aluminum were contacted with a large mass of water. Since laboratory tests were often carried out in the latter fashion, most of these have produced negative results. 

As with the smelt-water case, if an RPT did take place, the event was localized and rarely was dam e severe far from the site of contact. Modeling molten aluminum-water incidents (and, in fact, other molten metal-water explosions such as in the steel industry) has not been partic-... 

Several studies attempted to determine whether chemical reactions were occurring at the aluminum-water interface. The finding that there was some light emission and local high temperatures led to the conclusion that reactions do occur, and they may be of more importance in the more violent explosions. 

Besides the aluminum industry, the nuclear power industry has been interested in molten aluminum-water explosions due to the presence of aluminum metal in some boding water reactors. Certain accident scenarios lead to a meltdown of the reactor core with concomitant contact of molten aluminum and water. 

Results from extensive test programs on molten aluminum-water explosions have been reported by Long (1957), by Hess and Brondyke (1969), and by Hess et al. (1980). In almost all experiments, molten aluminum, usuaUy 23 kg, was dropped into water from a crucible with a bottom tap (see Fig. 9). In only a few tests was there instrumentation to indicate temperatures, pressures, delay times, etc. The test results were normally reported as nonexplosive or explosive—and if the latter, qualitative comments were provided on the severity of the event. A large number of parameters were varied, and several preventative schemes were tested. Over 1500 experiments were conducted. Some of the key results are summarized below. ... 

It is clear that the Alcoa research teams have provided a valuable data base to examine the mechanism of aluminum-water explosions. However, before considering proposed theories, the research studies at Argonne National Laboratory and elsewhere are summarized. 

Higgins quotes unpublished work at both Aerojet and DuPont that aluminum-water explosions were difficult to obtain, but alloys of aluminum with small amounts of lithium, sodium, or uranium were quite reactive. 

Extending this concept, we now consider those experiments which led to molten aluminum-water explosions without the presence of a wet, solid surface. In all of these there was an external shock applied to the system—usually in the form of an exploding wire or a detonator. As presumed by the investigators, these artificial shocks could be very effective in collapsing steam films. 

Anderson, R. P., and Armstrong, O. R. (1981). Experimental study of small scale explosions in an aluminum-water system. Pap., Winter Anna. Meet., ASME, 1981, New York. 

Dewing, E. W. (1980). The initiation of molten aluminum-water explosions. Memo., AIME Meet., 1980, Las Vegas, Nevada. 

The two volunteers seemed not to notice me. I watched with interest as one of them suddenly shouted into an aluminum water pitcher calling out to someone he evidently thought had fallen into a well. Abmptly distracted by my questions, he then attempted to take a bite out of a non-existent chicken. This thing is mbber, he said. He sounded like a politician, jaded from attending too many fundraisers. 

Aleshin et al, Calculation of the Thermodynamic Characteristics of Hydroreacting Aluminum-Water Fuels , Fiz AerdispersnykhSist 17,74—78 (1978) CA 91,76312 (1979) [Reported are the thermodynamic calcns made for the hydroreacting Al-w mixt used as a rocket fuel at a combustion chamber pressure of 40kg/sq cm]... 

Imai, H., T. Saegusa, S. Matsumoto, T. Tadasa, and J. Furukawa Polymerization of tetrahydrofuran by triethyl-aluminum-water system. Makromol. Chem. (in press). 

A preliminary feasibility exptl study indicated that simulated expls in a test box (cast DNT and an Amm Nitrate, sugar and water mixt) could be readily distinguished from the other items in the box (shaving cream, cologne, book, wood, aluminum, water) by dual-energy CT techniques... 

A large number of epidemiology and case-control studies have examined the potential association between oral aluminum exposure and Alzheimer s disease. A number of these studies have been criticized for flawed patient selection, poor comparability of exposed and control groups, poor exposure assessment, poor assessment of health outcomes, and weak statistical correlations (Nieboer et al. 1995 Schupf et al. 1989). Studies conducted by Martyn et al. (1989), McLachlan et al. (1996), and Michel et al. (1990) have found an association between oral exposure to aluminum and an increased risk of Alzheimer s disease. In a survey study conducted by Martyn et al. (1989), the incidence of Alzheimer s disease in individuals under the age of 70 was estimated from computerized tomographic (CT) records. The 1,203 subjects lived in 88 county districts within England and Wales. Data on aluminum concentrations in the municipal water over a 10-year period were obtained from water authorities and water companies. The subjects were classified as having probable Alzheimer s disease, possible Alzheimer s disease, other causes of dementia, or epilepsy. The relative risks of Alzheimer s disease were elevated in the subjects living in districts with aluminum water concentrations of >0.01 mg/L. However, the relative risk exceeded unity only in the subjects with aluminum water concentrations of >0.11 mg/L (relative risk of 1.5, 95% confidence interval of 1.1-2.2). 

Alveteg M, Sverdrup H, Warfvinge P. 1995. Developing a kinetic alternative in modeling soil aluminum. Water Air Soil Pollut 79 377-389. 

Birchall JD, Chappell JS. 1989. Aluminum, water chemistry, and Alzheimer s disease [Letter], Lancet i 953. 

Shuman LM, Wilson DO, Ramseur EL. 1991. Testing aluminum-chelate equilibria models using sorghum root growth as a bioassay for aluminum. Water Air Soil Pollut 57-58 149-158. 

FIGURE 21.15 Potential-pH equilibrium diagram for the aluminum-water system at 25 °C (from Ref. 27). 

Seamans, G.M. and Rehal, A.S., Electron metallography of the aluminum-water vapor reaction and its relevance to stress corrosion susceptibility, J. Mater. Sci., 14, 2459, 1979. 

CNC ARIDRY AA is a wax-type aluminum water repellent which is used as an excellent all-purpose repellent for synthetics. The product is also a napping aid for nylon and/or orlon fleece fabrics. 

Vesely J., Hruska J., and Norton S. A. (1998b) Trends in water chemistry of acidified bohemian lakes from 1984-1995 11. Trace elements and aluminum. Water Air Soil Pollut. 108, 425 -443. 

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