I don't know if anyone has ever looked into or lifted a CRT lately. Due to
flat screen and larger size, there is a tremendous weight that is not due
to electronics but rather to Lead Metal shielding for X-ray. The probable
reason for Plasma and LCD flat screen is to eliminate the Lead and reduce
the weight. These technologies eliminate the X-ray hazard also, so the
exemption will soon be meaningless for the new CRT industry.
James P. Canner
Senior Applications Engineer
Murata Electronics North America
1900 W. College Ave
State College PA 16801-2799
(814)-237-1431 x 2032
[log in to unmask]
Brian Ellis
<b_ellis@PROTONIQ To: [log in to unmask]
UE.COM> cc:
Sent by: Leadfree Subject: Re: [LF] Lead leaching
<[log in to unmask]
>
03/21/2003 04:26
AM
Please respond to
"(Leadfree
Electronics
Assembly Forum)";
Please respond to
Brian Ellis
Gordon
I agree with you entirely.
I was expanding on the false premisse of the EU regulations that forbid
lead in solder on leaching grounds. If that were valid, I was stating
that exempting CRTs and so on, would cause much more perceived harm than
lead-bearing solder because of both the mass and the solubility. It is
obvious that neither would cause harm in practice.
At least, no one seems to have thought about remelting CRT glass into
drinking vessels or vinegar bottles -- yet :-(
BTW, I believe the ultimate lead fixation in soil is cation exchange
with iron. Even lead carbonate, sulfate and sulfide have some solubility
in cold water (see CRC Handbook of Chemistry and Physics). Insoluble
iron complexes are found in most soils (except some desert sands) and
willingly give up some of their iron in favour of lead, forming a
compound which would release its lead only under extreme conditions of
chemical or thermal stress, decomposing the molecule.
I speculate now, but I have wondered whether EDTA salts, present in many
household and industrial products, would not tend to solubilise the
lead, though. Frankly, I have no idea.
Brian
Davy, Gordon wrote:
> Brian Ellis has contributed many interesting facts to this forum - his
> range of knowledge is certainly extensive. In a recent posting he has
> re-raised the notion that lead in landfills leaches into the ground
> water. He states that lead in glass is more easily leached than lead in
> solder. Brian is an expert in chemistry. In fact, he knows more than
> what he shared, and I feel compelled to present some relevant facts
> that he omitted. Even forum subscribers who aren't chemists know these
> facts, too, because they have all been stated here before.
>
> He knows that lead cations will remain in solution only until they
> encounter such anions as carbonate, sulfate, and sulfide, and he knows
> that all of these anions are present in ample supply in any landfill. It
> doesn't matter whether a CRT gets crushed into smithereens (nice
> technical term!). Yes, some of the lead will come out of the glass, but
> it won't get far before it is precipitated - permanently. He knows that
> the acetic acid leaching test used by the US EPA is grossly
> non-representative of what happens in landfills. He knows that landfills
> already contain plenty of CRTs, as well as car batteries, lead paint,
> and fallout from decades of burning leaded gasoline (this last not just
> in landfills, of course). He knows that the lead level in ground water
> is in the low single digits per billion, and is not changing. He knows
> that suppliers of drinking water control lead at the customers' taps by
> controlling the pH.
>
> I probably sound harsh, but we've covered this topic in this forum
> extensively, and I'm concerned to see this urban legend about lead
> leaching in landfills being perpetuated - by anyone, and for whatever
> reason. If we must be repetitious, at least let's make sure that what
> we're repeating is so. As we have observed often in this forum, relying
> on bad data can result (and has resulted) in bad decisions. In spite of
> all the legislation, enacted and proposed, the environmental impact of
> keeping CRTs out of landfills is nil.
>
> Even those who believe that forcing people to pay to keep CRT's out of
> landfills and incinerators and recycle them instead is a Good and Noble
> Thing should be willing to base their belief on all the relevant facts.
> (As I've said on more than one occasion, those who hold this belief
> arrived at it by some process other than studying a cost-benefit
> analysis, because no such analysis has been published - certainly not in
> this forum.) How can we expect to progress if we ignore what is known
> and keep repeating old errors and superstitions (not to mention the
> propaganda from those who have a financial stake in the outcome)?
>
> If I have been offensive in the way that I have said all this, please
> forgive my inability to figure out how to say it more diplomatically. I
> care about these matters, and feel obliged to respond in some way when I
> see misleading things being said.
>
> Gordon Davy
> Baltimore, MD
>
>
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