Posted on 08/10/2005 10:50:30 PM PDT by Dundee
SYDNEY (Reuters) - Australian scientists have developed a technique to use waste plastic in steel making, a process that could have implications for recycling scrap metal that accounts for 40 percent of steel production.
Professor Veena Sahajwalla of the University of New South Wales has won a prestigious Australian science award for what she calls "the hottest research in town," which she hopes will turn an environmental headache into a valuable resource.
Under the process, waste plastics are fed into electric steel-making furnaces as an alternative source of carbon and heated to super-hot temperatures of 1,600 degrees Celsius (2,912 Fahrenheit).
Sahajwalla said many waste plastics, from shopping bags to dishwashing liquid containers and drink bottles, contain high enough levels of carbon to be useful in steelmaking.
Carbon is used to add strength to steel. The higher the carbon content, the stronger but less ductile it is.
"What happens in a steelmaking furnace is that we are melting scrap steel, you can imagine if you've got your old cars and washing machines and so on," Sahajwalla told Reuters.
"The carbon component that's present inside plastic is what we're after and, at those high temperatures, we're able to react it in a way that we're able to use that carbon that's locked in the plastics. Typically you would add coal and coke," she said. Clyde Henderson, of coal industry newsletter Energy Economics, said similar technology using pellets of recycled plastic had been used in firing power stations in Japan. "I guess it's probably going to be, in terms of proportion of feed for these kinds of plants, a relatively minor kind of thing," Henderson told Reuters.
"I don't think the coal industry would see it as a threat. It's more an environmental angle, I think," he said.
Sahajwalla said her process did not replace all of the coal and coke, but still used a mix of plastic and coal.
Australia is the world's top coal exporter, shipping 122 million tonnes of metallurgical grade coal worth $9 billion ($6.8 billion) last year.
Australians use roughly a million tonnes of plastics a year, much of which ends up as waste destined for landfills.
"If you've got a whole lot of waste plastics that end up in landfill, not just in Australia but across the world, then it's really coming up with alternative technology for its disposal which is environmentally friendly," Sahajwalla said.
Sahajwalla, from the university's School of Materials Science and Engineering, won one of the Australian Museum's Eureka prizes for achievements in science for her work on Tuesday and said she was in talks about industrial applications for her project.
She said PVC was one of few plastics not suitable for the process because of potentially carcinogenic emissions when burned. ($1=A$1.32)
Tool and die Ping
Yea, that should produce some really nice pollution. :D Do ya like the smell of melted plastic?
If they can make diamonds out of peanut butter, why not?
My guess is that the cost of turning milk jugs to steel is astronomical.
I need to place an order for transparent aluminum.
I was sort of interested when I initially read this, but unfortunately they are still using coal. I was hoping that they were trying to reduce sulfur impurities in steel.
It's a neat idea, but it doesn't really sound that beneficial to me. The fact that you have to search out and remove all PVC would make me think that this would be more costly than coal. Of course, that's assuming that Australia has as strict an EPA and OSHA equivalent.
"It's raining beer!"
Never tried that. Wet and Messy? LOL
They already make beer that tastes like water.
It's like love in a canoe, right?
I would like go for the mile-high club someday before the ole willie looses it's wank. Just have to start hanging out with stewardesses I guess...
Not to mention that the chlorine that the process would leave embedded in the steel would the source for massive future corrosion.
Under those conditions, there wouldn't be any "smell of melted plastic"---the plastic would be broken down into its constituent atoms---carbon, hydrogen, and oxygen.
yea, why not PVC then?
Do I have to go and find my metalurgical hat now? Sheesh, just cook the steel till the carbon carmalizes and lets eat! :-)
Because PVC is "polyvinyl CHLORIDE" (i.e. it contains lots of chlorine atoms). When PVC is decomposed in the presence of molten iron, the result is formation of ferrous and ferric chloride inclusions in the resulting steel. And all of those sites in the metal are "hotspots" for corrosion.
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