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OT - glass...

OT - glass... - Physics Forum

OT - glass... - Physics Forum. Discuss and ask physics questions, kinematics and other physics problems.


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  #1  
Old 06-05-2005, 06:58 PM
ošin
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Default OT - glass...



Does it make sense to recycle glass?
Glass is inert, so what harm is there in puting it into landfill?
What are the energy costs and environmental impacts of recycling glass? Is
it better than using new raw silica?
What fraction of collected glass (intended for recyscling) actually end up
in landfill anyway?
Is there really much of a market for recycled glass? Is the quality and cost
on a par with new glass?
Does government funding get its value? Could that money be better used on
other environmental issues?


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  #2  
Old 06-05-2005, 08:00 PM
N:dlzc D:aol T:com \(dlzc\)
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Default OT - glass...

Dear opin:

"opin" <oš[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...

Google provides 137,000 hits using all the words:
glass recycle statistics

The first page full appear quite germaine.

Yes, it does make sense to recycle. It will make even more sense
as time progresses.

David A. Smith


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  #3  
Old 06-05-2005, 09:41 PM
JohnM
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Default OT - glass...

ošin wrote:
It does make sense to recycle glass, some glass has decent value as
scrap. Window glass, referred to as "flint glass", in my experience, has
the lowest value. Bottle glass's value generally depends on its color,
with brown being the least valuable and clear the most.

That is all based on my experience with the scrap industry some years
back, it might not be correct now but it probably is.

I built a machine for a small scrapyard which was trying to get into
scrap glass. It seemed to be a good deal, the price of steel was down to
where good grades of paper and glass paid better.

The problem for the yard operator came with the storage and handling of
the glass, moisture especially was troublesom; if it's not kept dry
it'll hold a remarkable amount of water, which you'll not only be docked
for but which will cost you load capacity- a truck full of scrap glass
will max out on weight long before volume, and the water was a major
waste and cost. Also, if the bottles have water in them before being
crushed then it's very difficult to deal with the result.

John
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  #4  
Old 06-05-2005, 10:31 PM
ošin
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Default OT - glass...

> It does make sense to recycle glass, some glass has decent value as scrap.

What about the fuel burned in picking up tiny bits at the curbside, in stop
and go traffic, throughout a large city and the bulk transport costs to the
recycling plant? What about the energy consumed in sorting and separating
the glass? What about the cost of cleaning, crushing, melting, etc.?
Why do I often hear that a large percentage of the so called re-cycled glass
ends up in a landfill site or is used for bulk purposes that were
traditionally filled with sand, soil, and gravel, such as pavement and
landscaping. Is that really recycling? Or is it the same thing as landfill.
What harm does glass do sitting in landfill?


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  #5  
Old 06-05-2005, 10:36 PM
ošin
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Default OT - glass...

>> Does it make sense to recycle glass?

Wow thanks for the hot tip...


Germane? How exactly?


When I asked "does it make sense to recycle glass?", I was hoping for more
of an answer than "yes, it does make sense to recycle". What are the energy
costs, what are the ecological impacts? Why do you feel that it make sense
to recycle?


Ummmmm.... Why?


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  #6  
Old 06-06-2005, 12:34 AM
tadchem
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Default OT - glass...


"ošin" <oš[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...
scrap.
stop
the
glass
landfill.

I believe the question could be better phrased as "Is it economically
practical to recycle glass?"

I don't have the answer right now.

I believe my late uncle was correct when he commented back in the 1960's
that landfills will be recognized as valuable deposits of resources and will
be economically mined by the end of the 21st century.

Considering the rate at which we discard electronics and the associated gold
and refined metals, some landfills may already assay out at higher values
than ores currently in production.

All that is really needed is a little development of reclamation technology,
especially in the classification (sorting and separating) processes.

Bottom line - the answer to your question is likely to change with time.


Tom Davidson
Richmond, VA


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  #7  
Old 06-06-2005, 04:32 AM
N:dlzc D:aol T:com \(dlzc\)
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Default OT - glass...

Dear opin:

"opin" <oš[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...

Oh, so you did your own search? And you didn't find the
answers...


Because they provide statistics regarding how much cheaper it is
to recycle glass than to make new from "dirt". They talk about
volumes of material. They have answers to the questions you
asked.


It isn't in a landfill, which becomes taboo for further
development. Any amount of volume NOT added is of worth.


The stuff is inert. Yet it is mixed in (if not recycled) with
biological waste (paper, food, plant matter, plastic). Glass
doesn't assist in breakdown. It doesn't dilute the pollutants.
It doesn't provide sites for biological remediation. It doesn't
wick water to locations that can help breakdown. So it doesn't
help convert a waste stream (eventually) to arable land, in fact
it retards bioremediation by acting as a shield.

Additionally, glass is already purified, a step that "virgin
glass" doesn't have. A simple wash and bake restores most glass
to the point that it can be reprocessed.

If I provide links, will you follow them?

David A. Smith


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  #8  
Old 06-06-2005, 06:51 AM
JohnM
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Default OT - glass...

ošin wrote:

I am unaware of any economic advantage in picking up tiny bits at the
curbside and I suspect that it's not generally done. As with all
commodities, the greater quantity is more profitable; while a shopping
cart full of scrap glass won't have enough value to transport far, a 20
ton load may.

The only concern in the energy consumption and other costs you mention
is whether or not the bottom line makes it cheaper to recycle glass than
to make new. If recycling glass is cheaper then it'll be recycled. The
ideal, from the point of view of the small scrap dealer, is for the
local public to bring it to a collection point and, as compensation for
their efforts, be pleased to be involved in recycling. While this
process certainly entails hidden costs, they are apparently acceptable.

Another source is bottling companies, in states where glass bottles have
a deposit. They will have no choice but to dispose of the glass,
preferably at a profit. They might deal with the second or third level
of the scrap industry, bypassing the local yard.

Glass that might be used in place of sand is certainly recycled- it's
being put to a second use. Again, if it's economical then it's a good
thing to keep it out of the landfill.

John
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  #9  
Old 06-16-2005, 02:26 AM
setanta
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Default OT - glass...


"JohnM" <[Only registered users see links. ]> wrote in message
news:42a3ef62$0$14997$[Only registered users see links. ] m...

It does make sense to recycle glass even though it is energy intensive it is
important to plant in the psyche that "recycling effort" on behalf of the
individual pays dividends in the long term.

I have looked at (in the past) melting glass using 2.45GHz MW - it is
necessary to "seed" the glass with a hot spot so that the MW can continue to
heat it - otherwise there is no effect.

I forget the figures now but using a multimode cavity it ewas more efficient
to melt glass in MW than in a furnace

Kieran


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