Tungsten electrodes

This is another line of scrap I've gotten involved in recently, tungsten electrodes from xenon arc lamps. The local recycler pays $6.00 per pound for tungsten. This is the second batch I've sold, and probably half of these were from lower wattage (2KW) lamps. The total amount of metal in the two photos was from 79 lamps and weighed 33 pounds. I don't have pictures of it but the first batch I sold was approximately the same number of lamps except they were higher wattage (mostly 3KW-6KW) so that batch was 57 pounds. The stuff is incredibly dense though. To give you an idea of scale that cardboard box is only about 4 inches deep, and the rods are I'm guessing 3/16 inch and 5/16 inch in diameter and mostly around 2 to 4 inches long. The rods seem to be sintered so they're somewhat brittle, which worked out well since a hacksaw really wasn't much use on them. I just broke the rods off where they were encased in the glass since it doesn't come off them very easily.

If anyone is interested - On a new lamp the larger electrodes (Anodes) have a flat blunted end and those little balls and nodules you see growing on them are usually the result of excessive hours of use, hot-striking lamps before they cool down, or excessive AC ripple on the power supply. Those nodules cause the arc to jump around and create flickering and can cause the arc to flame out or be hard to strike in the first place. Similarly the pointed electrodes (Cathodes) come to a very sharp point on a new lamp but you see many here are somewhat blunted. A couple here got the tips broken off while breaking the lamps open, but most were just worn down from use and the metal redeposited onto the anodes and the glass. That wear increases the gap between the electrodes and can also make lamps hard to strike or prone to flaming out.

macfixer01

$6 per lb - really - that's interesting because on mineralprices.com they list tungsten at $350 per ton which is $0.175 per lb although that is listed as tungsten (WO3) which would be tungsten trioxide

Kurt

http://www.scrapmetalforum.com/scrap-buyers-sellers/12714-scrap-carbide-tungsten.html

You may want to try this buyer for your tungten. Good buyer and he reimburses part of shipping costs.

kurtak said:

$6 per lb - really - that's interesting because on mineralprices.com they list tungsten at $350 per ton which is $0.175 per lb although that is listed as tungsten (WO3) which would be tungsten trioxide

Kurt

Click to expand...

Kurt,
They actually didn't have tungsten metal in their computer and just listed it as solids instead. I guess they're more used to buying tungsten carbide machining inserts as scrap, although I didn't ask what they pay for that? You have me wondering now about the WO3. So atomic weight for tungsten = about 184 / 232 for WO3 so about 79% tungsten? Pricing may have something to do with country of origin, or just the fact that the metal doesn't need nearly as much processing as raw ore would? It's got to be expensive to refine tungsten from the oxide given the high temperatures needed?

yar said:

http://www.scrapmetalforum.com/scrap-buyers-sellers/12714-scrap-carbide-tungsten.html

You may want to try this buyer for your tungten. Good buyer and he reimburses part of shipping costs.

Click to expand...

Hi Yar,
It looks like this guy only buys tungsten carbide machine tools and inserts, but I'll contact him next time I get a batch together. I also got a PM from a forum member I'll be contacting as well.

Thanks,
Macfixer01

macfixer01 said:

kurtak said:

$6 per lb - really - that's interesting because on mineralprices.com they list tungsten at $350 per ton which is $0.175 per lb although that is listed as tungsten (WO3) which would be tungsten trioxide

Kurt

Click to expand...

Kurt,
They actually didn't have tungsten metal in their computer and just listed it as solids instead. I guess they're more used to buying tungsten carbide machining inserts as scrap, although I didn't ask what they pay for that? You have me wondering now about the WO3. So atomic weight for tungsten = about 184 / 232 for WO3 so about 79% tungsten? Pricing may have something to do with country of origin, or just the fact that the metal doesn't need nearly as much processing as raw ore would? It's got to be expensive to refine tungsten from the oxide given the high temperatures needed?

Click to expand...

Or there's something else in the alloy that's more valuable that you don't know about. I sold several tons of what I thought was stainless steel valves many years ago for thirty cents a pound. Between loads, the scale house guy was talking about a load of Monel coming in. I left with what I had and did some checking. The valves were Monel and not stainless steel. I went back to talk to the owner and he said he could not adjust what I already sold but he could adjust anything I brought after. I forced the price of stainless steel to rise at all local scrap yards to $.50 per pound because of it. Just because I overheard the weigh master talking too loud, it doubled what I was getting for the same material.

macfixer01 said:

yar said:

http://www.scrapmetalforum.com/scrap-buyers-sellers/12714-scrap-carbide-tungsten.html

You may want to try this buyer for your tungten. Good buyer and he reimburses part of shipping costs.

Click to expand...

Hi Yar,
It looks like this guy only buys tungsten carbide machine tools and inserts, but I'll contact him next time I get a batch together. I also got a PM from a forum member I'll be contacting as well.

Thanks,
Macfixer01

Click to expand...

As far as I know he will buy tungsten and carbide in any form. Check out his videos on that post I linqed.

Geo said:

macfixer01 said:

kurtak said:

$6 per lb - really - that's interesting because on mineralprices.com they list tungsten at $350 per ton which is $0.175 per lb although that is listed as tungsten (WO3) which would be tungsten trioxide

Kurt

Click to expand...

Kurt,
They actually didn't have tungsten metal in their computer and just listed it as solids instead. I guess they're more used to buying tungsten carbide machining inserts as scrap, although I didn't ask what they pay for that? You have me wondering now about the WO3. So atomic weight for tungsten = about 184 / 232 for WO3 so about 79% tungsten? Pricing may have something to do with country of origin, or just the fact that the metal doesn't need nearly as much processing as raw ore would? It's got to be expensive to refine tungsten from the oxide given the high temperatures needed?

Click to expand...

Or there's something else in the alloy that's more valuable that you don't know about. I sold several tons of what I thought was stainless steel valves many years ago for thirty cents a pound. Between loads, the scale house guy was talking about a load of Monel coming in. I left with what I had and did some checking. The valves were Monel and not stainless steel. I went back to talk to the owner and he said he could not adjust what I already sold but he could adjust anything I brought after. I forced the price of stainless steel to rise at all local scrap yards to $.50 per pound because of it. Just because I overheard the weigh master talking too loud, it doubled what I was getting for the same material.

Click to expand...

Well the lamps are from a couple different manufacturers and they generally don't give such details. From general info I read about tungsten online though, in vacuum tubes they used a bit of Thorium in the tungsten electrodes to enhance ionization. These lamps have internal wire coils or an external wrap of wire used to cause ionization for striking along with a jolt of high voltage AC. I also read that in tungsten welding electrodes a bit of Thorium improves the arc characteristics. Neither situation seems directly relevant though. If so it may be slightly radioactive which may scare some folks, but Thorium is also present in the cloth mantle bags used on Coleman lanterns. On the other hand it was hard to find anything definitive but Thorium currently seems to have a price somewhere around $5000/KG!

If anyone is interested I finally got around to making a video on scrapping xenon lamps for tungsten. Apparently some of the other techs in my company are getting as much as $10.75 per pound down south in Florida and Texas. I still can't figure out why there is such a disparity in prices?

http://youtu.be/gPf7p7c5jyU

Macfixer01

Nice video.

macfixer

You might want to check this company out for selling to - I have not talked to or done any business with them so would be interested in what you find out if you talk to them - according to their web site they buy a lot of metals (rare earth, exotic, high temp, etc.) that most scrap yards don't deal in

:arrow: http://www.titanscraprecycling.com/

Kurt

We sell and dispose of tungsten too if you wanna shoot me a PM.

Thanks for the replies. I recently contacted the company yar had suggested awhile back, but once I told him they were xenon arc lamp electrodes he said they don't buy them because of their Thorium content. He said some companies do and some don't, just shop around. Thorium is an alpha emitter and alpha particles can't penetrate the skin. I know they also use some in welding electrodes, and Thorium salts are used in Coleman lantern mantles. I didn't think it was that big of a concern? I'll try that other company on Monday that kurtak suggested, and send Lou a PM as well.

Thanks again!

macfixer01

I had some of these hit with an xrf gun and it was 95% tungsten 4% tantalum trace iron and other metals.

Every one of those lamps should have platinum clad moly seals.

Lou said:

Every one of those lamps should have platinum clad moly seals.

Click to expand...

Hi Lou,
Your comment about the seals got me interested, so I did some more searching and found this PDF from Osram which describes their xenon arc lamp design aspects and function. I believe the type of lamps you're talking about would be those they describe as having type 1 seals? They describe type 1 as having molybdenum ribbons embedded in the quartz glass that supply the electrical connections from the outside terminals to the tungsten rods which support the internal electrodes. Those would appear to be used on lower wattage lamps since it says they're limited to about 10 Amps, so perhaps a few hundred Watts max? The lamps I'm getting are between 2000 and 4500 Watts and the larger ones operate at well over 100 Amps. They have seals similar to the type 3 described in this document. That explained to me some design aspects I had wondered about on Christie lamps, such as the sections of support rod wrapped in thin foil and closely surrounded by glass but not fused to it. The glass will actually slide off the rod once the it's broken free from the rest of the envelope. I get a few Osrams and Philips, but mostly Christie lamps. The Christie's have two thin strips about 1/4 inch wide of a slightly bluish metal I suspected might be molybdenum? The strips are wrapped in rings around the support rods right next to the anode and cathode. Underneath the strips right where the rods actually enter the electrodes are a few turns of tiny tungsten wire with it's ends twisted to prevent unwrapping. Unfortunately I can't find any similar document online for the Christie's that explains their construction or reasoning for odd details such as that? I can only assume they help insure the conductivity from the external connections to the electrodes? It's hard to imagine they're needed at the kind of currents these operate at though, and I see nothing similar on other brands.

http://assets.sylvania.com/assets/documents/ENGR_BLTN11.161355cc-1d94-4996-b6cd-a3001fea6f1a.pdf

Macfixer01

I just know that I processed several spools of Pt/Mo ribbon tape that was used to make xenon arc lamps.

I put it in a tube furnace and ignited in oxygen at 900C to leave pure Pt behind and MoO3 sublimate was caught in a caustic scrubber as sodium molybdate. The platinum as left behind as ribbons which were chemically pure.

Lou

That sounds very interesting, I got some arch lamps used in spectrometers, they are at a couple of hundred watts each. I have to check them when I get back home and I'll put up some pictures of them even if it's lacking PGM:s.

Last batch I sold at a dollar a peace to people building lasers.

Göran

kurtak said:

macfixer

You might want to check this company out for selling to - I have not talked to or done any business with them so would be interested in what you find out if you talk to them - according to their web site they buy a lot of metals (rare earth, exotic, high temp, etc.) that most scrap yards don't deal in

:arrow: http://www.titanscraprecycling.com/

Kurt

Click to expand...

I tried to go to this site and the link is broken.
I searched google and the top results are not good.
http://www.ripoffreport.com/r/titan...am-theft-fraud-highland-park-illinois-1189449

If anyone reading this old thread has tungsten rods from scrap with a diameter about 1/4 inch or 6 mm and any length (from xenon lamps or other source) for sale, please send me a PM.