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[GreenYes] Re: Green Mountain Glass

On Jan 19, 2007, at 10:50 AM, Doug Koplow wrote:
Any opinions on the environmental profile of decolorized cullet
produced by Green Mountain Glass?
It seems like it would be a great way to recover large quantities of
cullet into higher value markets. Are there downsides in terms of
byproducts or processing energy? Has it been tested in high volume

I'm going to carry on here a bit because I believe people need to
view these things critically, and to understand what's new and what's

The idea of decolorizing colored glass for re-use goes back a long
way, see for example:
patent 2955948 GLASS DECOLORIZING METHOD Oct 11, 1960
BORATE GLASS Dec 9, 1969

I managed this re-colorization project in 1996: Color Modification of Post-
Consumer Glass Cullet

The web site
makes the following statement:
"technique and formulation allowing for the decolorization and
colorization of multicolored glass"
which makes it sound like they're turning green glass clear. But the
only capability claim they make on the site, that I see, and on the
video, is to make amber glass using 40% 3-mix, which is fine, but not
hardly as big of a deal.

On the video, the technologies of optical sorting and eddy current
removal they describe are of course currently being used in virtually
all large-scale recycling plants in the country now. So the new part
starts after the 3-mix clean up.

The new part seems to be the automated mixing, and addition as needed
of coloring and batch modifying compounds, to produce amber bottles.

The challenges that do not appear to be addressed are:
Okay, you can make amber glass from 40% 3-mix. Is there a market
for amber glass bottles large enough to support a 100,000+ ton per
year plant costing $100,000,000 near you? 80,000 tons per year is
the smallest glass container plant I know of in the U.S. Scale
dictated by economies of scale.

Glass has been losing market share for over a generation. Glass
plants are closing. Is there a shortage of beer bottles?

Even with the advantages of energy and emissions, the ceiling for
processed value is set by virgin materials, which continue to be
plentiful and inexpensive.

You still have to ship it both before and after processing or
manufacturing. Years ago Argonne Labs did a study calculating that,
for the purpose of break-even energy consumption from the use of
recycled glass in glass manufacturing, a one hundred mile radius was
about the max it was rational to ship glass by truck.

These are obviously smart guys who know their glass chemistry. I
just wish it wasn't hyped for more than it is.

Bob Kirby

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