# Lost Treasure - Tungsten Carbide



## Anonymous (Feb 14, 2010)

While browsing the Virtual Machine Shop came across this interesting tidbit on tungsten carbide, thought I would post it as another source of precious metals.

Some carbides are silver soldered to a steel shank while others are affixed by either a screw or clamping system, there are many grades, sizes and shapes of tungsten carbide inserts - Harold_V would be most familiar with these and their uses.

Other sources for the tungsten carbide, saw blades, rotary rock drills, percussion drill bits and spades used in hammer drills and the larger Jack to name a few.

This would explain why so many are advertising to purchase scrap tungsten carbide.

Credits go to Virtual Machine Shop http://www.jjjtrain.com

Carbides are made by blending micron-sized tungsten carbide and cobalt powders, then pressing the mixture in a mold and at a temperature high enough to cause the cobalt to flow. During this process the cobalt fills the spaces between the tungsten grains and thoroughly coats each grain. When the cobalt solidifies, it cements the grains together, forming a dense composite. This process is called "sintering" and the resulting tool is called "cemented" carbide.

Cemented carbides get their hardness from the tungsten grains and their toughness from the tight bonds produced by the cementing action of the cobalt metal*. By varying the amount of cobalt the hardness, wear resistance and toughness (shock resistance) of the carbide can be changed.

The beginning of tungsten carbide production may be traced to the early 1920's, when the German electrical bulb company, Osram, looked for alternatives to the expensive diamond drawing dies used in the production of tungsten wire.

These attempts led to the invention of cemented carbide, which was soon produced and marketed by several companies for various applications where its high wear resistance was particularly important. The first tungsten carbide cobalt grades were soon successfully applied in the cutting and milling of cast iron. In the early 1930's, the pioneering cemented carbide companies launched the first steel-milling grades which, in addition to tungsten carbide and cobalt, also contained carbides of titanium and tantalum.


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## qst42know (Feb 14, 2010)

Though you may be able to recover some silver from brazed carbide tools. 

It takes very few inserts to make a pound $8.25-$9.25.

Ideally leach the silver then scrap the inserts. :mrgreen: 

http://www.metalprices.com/FreeSite/metals/tungsten_carbide/tungsten_carbide.asp

http://www.minormetals.com/


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## butcher (Feb 14, 2010)

I have seen boxes of that type at scrap yard.


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## scrapman1077 (Feb 14, 2010)

I collect and scrap carbide all the time, once removed from the steel a soak in nitric removes the solder and you have upgraded the carbide, most but not all have silver solder, I have cleaned 100s of pounds of "road razer" tips, the tips they grind asphalt before repaving, they are just base metal solder. And, yes you can get a good amount of silver this way.


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## scrapit (Feb 15, 2010)

The carbide that is found I'm machine hops and on other things is worth way more than the silver if you have a lot of soldered tips it would be eased to stick them all in a large pot ant put it in the fire and shake it when it gets hot enough to melt the soldier then pour off the silver while its still hot


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## Barren Realms 007 (Feb 15, 2010)

scrapit said:


> The carbide that is found I'm machine hops and on other things is worth way more than the silver if you have a lot of soldered tips it would be eased to stick them all in a large pot ant put it in the fire and shake it when it gets hot enough to melt the soldier then pour off the silver while its still hot



Is this from prctical experience that you have done this? Or just some suggestion you are throwing up in the air?


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## Harold_V (Feb 16, 2010)

Barren Realms 007 said:


> scrapit said:
> 
> 
> > The carbide that is found I'm machine hops and on other things is worth way more than the silver if you have a lot of soldered tips it would be eased to stick them all in a large pot ant put it in the fire and shake it when it gets hot enough to melt the soldier then pour off the silver while its still hot
> ...


My money is on the air concept. There's no way in hell (all) the solder will be removed by that method. 

While silver has greater value, there is a ready market for tungsten carbide. Removing traces of solder with dilute nitric is a very good idea. Done cold, there should be little action on the carbide, and the value of the recovered silver will offset the cost of the acid and net a small profit. 

Harold


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## scrapit (Feb 17, 2010)

I scrap all kindsbof metal for extra cash and I have melted the carbide heads off of cutting tools before. Carbide is $8 to $10 a pound sometimes more depending were you go and how much you have. You don't get much soldier off of the carbide heads. You would need a lot of carbide tiled tools to make any money. I just put an add in the silver section about coin silver flatware that would probably be more profitable than the soldier idea. But you never know.


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