Good Grief! The first thing that pops up when somebody talks about a new product or process, somebody has to start jabbering about hazards and safety. Almost any process can be done in an unsafe manner, but most processes run better and more consistently when they are done in a controlled and stable manner, rather than uncontrolled or unstable.
While many types of dust are combustable, graphite is fairly stable. In fact it is difficult to get it to burn. Soot is a different story, but it is also a different form of carbon. Letting any form of dust escape from a process will reduce the yeild, so the smart operators will avoid dust emissions. The fact is that breathing almost any kind of dust is harmful to some degree, and so the process would naturally be designed to avoid dust emissions.
So it is really a bit prematuyre to be talking about safety concerns.
A bigger concern is energy efficiency, does it take less energy to recycle than to use raw materials? That would be the main concern, and what might limit the adoption of the process.
Chuck, the end-apps mentioned that are relevant to our audience seem to cluster around automotive, aerospace, and industrial markets, the markets served by the commercial members of the consortium. The demonstrator products include press-molded automotive parts. The original materials produced that can then be fashioned into products, however, vary widely: yarns, tapes, textiles and other fabrics, and sheets.
naperlou, I agree. As an industry, CFRP producers and even large users such as Boeing are making an effort to deal with the results of the anticipated increasing volumes and all that material entering the waste stream down the line. I haven't seen this yet in other materials classes, although I'm certainly looking for indications. Also, notice that this is occurring in Europe, not the US. They are way ahead of us in so many regards when it comes to green engineering and environmental considerations.
Given that carbon is combustible a dense aerosol could ignite and explode in the same way as flour or grain dust. I would hope that both economics (the stuff is too valuable to let it blow away) as well as good industrial practice would prevent such conditions.
A third concern for the aerosolized carbon fibers would be the possibility of explosion sparked by static discharge. Let's not forget the lessons learned from the flour mill explosions of the 1940's and 1950's.
Before we get too carried away with carbon fibers we should pay attention to two risks. Both deal with carbon fiber aerosols. First, are they bad for you inhale? We don't want a repeat of the asbestos history where we used this wonderful fiber for decades before we recognized the health hazards.
The second is that unlike most other fibers (cellulose, asbestos, glass, etc.), carbon is conductive. If airborne carbon fibers drift into electronic equipment they can short the close-spaced connections and cause a lot of mischief.
Carbon fiber is wonderful stuff, but let's be careful.
The 50% reduction in tensile strength means that some applications are eliminated from possibility. Ann, do we know some of the target applications and do we know if some are already using these materials?
This is great news which I think plays into the eventually lowering of costs of composites and thus the broadening out of applications from aerospace into automotive, where costs are more of a concern. I addressed some of this in this story, "CES: Mercedes Foresees Progress in Batteries, Composites," where an engineer there said he does indeed expect costs to come down as companies come up the learning curve. Another recent data point is that BMW is building a factory in Washington State to produce composites for its upcoming i5 and i8 hybrids.
Yes, all materials must be separated before recycling. One of the big problems with composites is the adhesives involved, which make that difficult to do, and which make the result difficult to recycle with heat processes and still end up with enough strength and durability.
Regarding volumes, not anytime soon. But that's because these efforts are at their very beginning, so their growth rates could remain high for a long time before the volumes approached the current consumption rates.
Do these products need to be separated as they go into re-use or do they all get dumped in together? I'm also curious as to whether re-use projects such as the one you describe in this article and in other articles (Ford and bridges) are likely to make a dent in the growing mountain of these materials.
Fifty-six-year-old Pasquale Russo has been doing metalwork for more than 30 years in a tiny southern Italy village. Many craftsmen like him brought with them fabrication skills when they came from the Old World to America.
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