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Aluminum loves air. If aluminum is exposed to air it creates a skin that prevents further interaction with air. And aluminum is pretty non-reactive in water. This is why aluminum is used many times in boats and such. Aluminum works well in scenarios where rust is unwanted. Jerry Woodall and his team at Purdue have found that gallium and aluminum alloys, when mixed with water, produce hydrogen. And Woodall’s discovery was accidental.
Woodall was working in the semiconductor field in the late 60’s. “I was cleaning a crucible containing liquid alloys of gallium and aluminum,” Woodall said. “When I added water to this alloy - talk about a discovery - there was a violent poof. I went to my office and worked out the reaction in a couple of hours to figure out what had happened. When aluminum atoms in the liquid alloy come into contact with water, they react, splitting the water and producing hydrogen and aluminum oxide.”
“Gallium is critical because it melts at low temperature and readily dissolves aluminum, and it renders the aluminum in the solid pellets reactive with water. This was a totally surprising discovery, since it is well known that pure solid aluminum does not readily react with water.”
The non-reactive Gallium can be reused. The aluminum by-products can be recycled. The hydrogen can be used to power a car, a truck, a computer, etc. And I guess there is the water by-product. No toxic fumes are emitted during the process. Overall, it seems like a brilliant idea.
“Most people don’t realize how energy intensive aluminum is,” Woodall said. “For every pound of aluminum you get more than two kilowatt hours of energy in the form of hydrogen combustion and more than two kilowatt hours of heat from the reaction of aluminum with water. A midsize car with a full tank of aluminum-gallium pellets, which amounts to about 350 pounds of aluminum, could take a 350-mile trip and it would cost $60, assuming the alumina is converted back to aluminum on-site at a nuclear power plant.
“How does this compare with conventional technology? Well, if I put gasoline in a tank, I get six kilowatt hours per pound, or about two and a half times the energy than I get for a pound of aluminum. So I need about two and a half times the weight of aluminum to get the same energy output, but I eliminate gasoline entirely, and I am using a resource that is cheap and abundant in the United States. If only the energy of the generated hydrogen is used, then the aluminum-gallium alloy would require about the same space as a tank of gasoline, so no extra room would be needed, and the added weight would be the equivalent of an extra passenger, albeit a pretty large extra passenger.”
So, this concept is promising on many different levels. It would seem that the next step would be refining the process and coming up with concepts that utilize the idea.
Source: Purdue University
Photo Source: Purdue News Service photo/David Umberger
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Obviously this team is crazy, judging from the photo of three students, one with protective lenses, one with ordinary glasses, and one with and eye injury, all looking at a tube (of aluminum and gallium?) that might blow up in your face.