4 Pounds of Lead?

I don't know any factoids in this case, but I agree it sounds a bit out of order - what radio station was it? Do they have a website with 'listen again' or transcripts? It would be nice to nail this one!

The report is accurate. Large CRT's have over 5 pounds of lead typically, try a google search.

The lead is contained in the thick front glass and exists as lead glass...like lead crystal. This intercepts xrays caused by the electrons hitting the front phosphors ahd shadow mask.

There may also be small amount of lead in the tin lead solder of older monitors. New monitors do not use tin lead solder.

The lead in the glass is well bound and does not mobilize into ground water easily = red herring.

Most of the lead in a CRT is in something called the "frit", which joins the funnel to the front plate, and it apparently is leachable and therefore of much concern.

The amount of lead in a typical CRT apparently ranges between 1.5 and 5 lbs, depending on size, type and place of manufacture, with large color CRTs having the most.

Lead is also still a major component of solder for electronics and other purposes, having been actually eliminated only in the plumbing solder used to join pipes, fittings and parts carrying potable (drinking) water.

Are you sure it is Lead Glass? I think that should cost US$4000 plus if they can put that many kG of glass in that optically thin tube. I think you are taking people for a ride or making fun of their knowledge?

Any proof? I am giving you five point for this information and I should find it right.

http://www.google.ca/search?hl=en&q=xray+%2Bshielding+%2B%22lead+oxide%22&btnG=Google+Search

Dear Aurizon

Where it says that computer monitors are lead glass and they have in kgs. I know what Lead Glass is. I am a Radiological Physicist and work in cancer hospitals and has been nuclear scientist for two decades. It is a specific question here. Is the glas used in the CRT monitors a lead glass having few kg in weight? Is that a lead glass at all?

Yes, it is a true melt based glass. By adding various metal oxides to the formulas for glass you can create a huge array of glasses without the contraints of any crystallinity requirements. For x-ray shielding they add as much as they can before they cause other working properties of the glass to deteriorate.

the end use determines the ingredients, pyrex is one, with borax added for lower thermal expansion coefficient.

We understand what is the meaning of Glass and that it is not a crystal. Lead glass becomes yellow and less transparent to light. Ph, Ni, Cd are optical poisons in glass or crystals and are kept at minimum level such that they do not kill light. If lead is used in glass then it will not be clear display.

I have three LG picture tube plants 18km from my place and they sell these to almost all manufacturers of CRTs in India. I will find out from them and will let you know the exact stuff they use.

I believe that there is some kind of lead film at the back side of the tube and nothing in the front side. There is also thin film of conducting layer at the front side which forms an anode. This can't be too thick and not sure if that is lead. It can be anything in metals of very high conductivity and perhaps silver will be the right choice.

Shyam writes: "If lead is used in glass then it will not be clear display."

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Leaded glass CRT faceplates have been common for years, especially in color CRTs whose higher operating voltages produce copious amounts of xrays. I've never seen a CRT not be clear because of lead content.

Another counterexample, of course, is Waterford Crystal - a type of lead-glass containing up to 33% lead. Waterford Crystal is famous the world over for its sparkle and shine - and clarity.

All the radiology labs I've seen have used lead-glass windows. None of these suffered from clarity problems.

And do I take it (still, even still) that Google immediately stops working once one enters India? You do have search engines there, do you not?

-e

Lead. Pb. Hazardous. Really? Is mankind going over the top? There is a factor of 100 on this contained in the lead roof flashings of virtually every house in the UK. So why are "weee" worried about the substance?

BTW, the LD50 for water in humans is about 18 gallons. Sorry. 81.72 litres. One can drown in 5.

solder heaven that interpretation of factoid is malarky. only lead in puter is the solder. milligrams per unit..

Nope, they do indeed use lead, as that makes the front glass as this as possible.

large crt's have a negligable (ppm) amount of leas included..

See <http://www.uoregon.edu/~recycle/PDFdocuments/g2g_final.pdf> for more information. The lead in the PbO form is incorporated in the glass. Some has been replaced with BaO in late models.

The report was not overstated!

This is perhaps the story you heard, it is old but gets repeated quite often.

http://www.npr.org/programs/morning/features/2002/jul/recycling/

The lead is primarily bound up in the glass of the computer monitor. being that the average CRT monitor weight 30 - 35 lbs, it is conceivable that there is 4 lbs of lead in an entire PC, but I would say that the vast majority of it is bound up in the glass and not really able to leach into the environment.

There is quite a bit of Pb used in computors not including the monitors. This is a huge health risk. Look at Asia, they have fields of computors sitting in the mud and the Pb in leaching into the water supplies. People who live around or work in these material recovery operations are at high risk. It is another reseason North America should not be allowed to ship e-scrap over seas. Our company processes 600 tons/month of e-scrap not including CRT's, and you will find 3% Pb content just on the floor sweepings.

Lead has been eliminated from all new circuit board production and all copper pipe joining. We still have the installed base of this stuff and in time the problem will be solved. I would say in about 5 years the Board scrap will be 90% lead free or more

This Lead business is very funny. It allows tons of lead in Lead acid batteries and nothing on its control circuit. It is some kind of Joke I suppose played by those XRF machine manufacturers. They are using their lobby to make sure they make money. No one can get rid of Lead fully then what is fun in removing few grams of it. If you use it in roof and floor of your house then you may save yourself from cosmic radiation a bit better and live longer without cancer.

lead nitrate, chloride and a few others will dissolve in water. You can also get varied forms of lead with different valence, lead PbCl2 and PbCl4 and differing toxicity. the Cl4 is very toxic indeed.

Bound in a glass it is not soluble

Lead oxide is something that forms on exposure to air. Other forms are not so common unless they are salts present in earth. Lead bricks are used in tons in nuclear estabishments for shielding. They don't simply go inside some one's body. Both Sodium and Chlorine are toxic but we can eat salt happily. We need to worry what matters to us.

Entire world can sell all the lead to india and we can buy all that. This lead stuff has raised the price of lead acid batteries by 50% in India now.

http://www.epa.gov/epaoswer/non-hw/reduce/wstewise/pubs/g2gfinal.pdf

and this one states the front glass is lower in lead, but gets it's xray shielding via thickness.

http://www.ees.ufl.edu/homepp/townsend/Research/CRT/CRTDec99.pdf

That is very good information indeed. LG makes for Samsung in India and they use <1%. LG also makes for their own use. Perhaps that is why I have not come across such tubes in india. Most of the tubes are made in the plants of Hotline LG in India and they have four locations and with massive plants for CRT manufacturing.

Lead is heavy so others CRT must be very heavy. Just by weight one can find out what is inside the tube.

To recycle monitors the neck, envelope(if any) and shadow mask metals are separated from the glass components, smashed to small sizes and washed in very hot water with potassium hydroxide to remove the prosphors.

The remaining glass can be recycled into other glass products or disposed of as the lead is not mobile.

All the recycler sites say terrible things about the lead in the gass. It is almost harmless, being bound. The only lead you need worry about is that is any lead solder and the electrodes, phosphor and shadow masks metals

Trying to minimize the effect of lead on the environment by going after electronics and the lead in the glass that is used to make CRT seems to be putting the cart before the horse. Has anybody ever done looked at how much lead gets into the environment from things like ammunition and fishing tackle. This lead is in a pure form and leached into the environment far more readily than that in the glass in a CRT. To me the lead from a single fishing tackle weight or bullet poses many time the risk to the environment that the lead in the glass of a CRT or PCB.

I could be wrong but, this whole thing about lead in the environment from electronic equipment seem to be an over reaction by people that havn't thought the thing through fully.

lead metal passivates and little come from it in roofing etc. A lot of CO2 and SO2 in the air can mobilize lead and is part of the reason that lead and copper do not endure as long as they did in the middle ages as roofing materials.

I am not sure if lead is barred from old roofing? I think it is barred from new installs

It is a problem in fishing and hunting as ducks take up small stones for their gizzards and these perform the role of mastication and the lead is gradually worn down and some it metabolized into duck meat. Recent move to steel shot have halted this process and the lead in ducks and fish is declining now.

Lead free fuel was introduced first as environmental hazard reduction measure and was a very good step. Lots of lead comes in air due to road traffic. This also is airborne and easily goes into lungs and is where people are.

Perhaps electronics garbage may be increasing the world more rapidly so all these measures may be worth appreciating.

"lead metal passivates and little come from it in roofing etc."

So if what you are saying, that a lump of lead isn't a problem, is true, then why is it a problem when it is used as part of the solder in a PCB. It just doesn't make sense that the miniscule amounts of lead in electronic equipment could cause anything like to problems that the lead from various other sources like bullets, roofing, fishing tackle, etc.

"It is a problem in fishing and hunting as ducks take up small stones for their gizzards and these perform the role of mastication and the lead is gradually worn down and some it metabolized into duck meat."

Swans do the same thing as ducks. It has been shown that the population of swans in Australia have been ingesting led in this way except the source is fishing tackle weights. My question is therefore lets get rid of the major sources of lead contamination first then assess the minor sources.

This whole thing about lead coming from the solder used in electronics just doesn't add up. Look at the amount of solder manufactured and consumed around the world and compare it with the amount of lead used in ammunition and fishing tackle. Then consider the fact that nearly all the led in the latter two will end up in the environment and tell me that solder and lead glass are a problem.

It just doesn't add up!

Lead was alloyed with tin in boards and in pipes. This reduced the melting point but made the lead corrode more rapidly. The lead in boards that were discarded was found to mobilize into ground water from land fills and into the air from incinerators with no bag house. Acid rain also mobilized more lead from roofs, leading to a reduction in use. In addition lead roofind was skilled work and they lost the race with tar and felt that used much less skilled labor.

shot has been a problem in waterfowl for a long time. We just ate the lead in the fowl and said nothing. (I do not mean the balls, but the tissue lead)

in the past 10 years steel shot has replaced lead and the residual lead has mostly sunk out of the reach of foraging ducks and swans, so this is solved.

http://www.gunnersden.com/index.htm.steelvslead.html

http://findarticles.com/p/articles/mi_m3197/is_n5_v35/ai_9056917

Interesting information about shot. I am not sure whether this has been done it Australia but it is a positive step. What about ordinary bullets, I know that high velocity rounds use copper jackets over lead but has anybody looked at what happens to these projectiles. Also has the sport of fishing moved away from using lead weights in the tackle? In Australia the major problem is these fishing tackle weights rather than the lead shot and there has been absolutely no move away from the use of lead.

They are trying in Australia.

http://www.lead.org.au/clp/products/products.html

http://www.google.ca/search?hl=en&q=australia+%2Blead+%2B%22fishing+tackle%22&btnG=Google+Search

They have also developed a lead free dynamite :)

The use of lead shot for fishing weights has been illegal in the UK for several years now.

Perhaps the reason for PCB with lead may be due to putting them in fire and making lead to evaporate in air. It can also be due to putting these in dumping ground. Sheet of metal as shield is something that can be fully recovered and it is not very cheap either. Lead is soft and hence some support is required for it. Perhaps can be embedded in other sheets.

I want to inform you that in south India, people use Lead vessel for cooking food and they do even now. They make highly acidic soup in it called "RASM" which is basically tomato soup. Lead is a catalyst and gives much better taste. I am not sure if some one has analyzed the associated problem.

Similarly, some people used copper water cans or tumblers. Copper oxide kills germs and is also poisonous. People avoid putting the vessel in mouth and drink water by pouring from distance.