# Dental Scrap



## starzfan0211 (Mar 5, 2008)

I had to take my daughter to the dentist yesterday and after seeing the bill for her root canal and crown and picking myself off the floor, I asked what they did with their metal scrap. He told me that someone either came by on occasion or they package it up and send it out. I asked if I could pick it up from them and he said no problem. They have to sterilize it first.

I went home and told my son about it and after he got over being grossed out about the fact that some still have teeth in them, he decided that he is going to call the dentist offices in town over spring break and see if we can get more. He is a definite go-getter. 

Just to let ya know that you never know unless you ask! Every little bit helps.


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## peter i (Mar 6, 2008)

I've tried a bag of dental scrap once: By all means, burn it before doing anything else. The amount of "organic matter" in it will totally gum up your chemistry, and the smell is horrible.

A few minutes at a low red heat, and the problem is solved.

BEWARE OF MERCURY!


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## Harold_V (Mar 6, 2008)

peter i said:


> I've tried a bag of dental scrap once: By all means, burn it before doing anything else. The amount of "organic matter" in it will totally gum up your chemistry, and the smell is horrible.
> 
> A few minutes at a low red heat, and the problem is solved.
> 
> BEWARE OF MERCURY!



Absolutely------including under gold crowns. It was very common to find silver amalgam under crowns when I refined. 

Some of the white metals are platinum alloys, so don't discard according to color. The high temperature alloys tend to be a blue silver color, and very brittle. They'll usually break when you attempt to bend them. The other alloys are somewhat more ductile, but still quite hard. 

When you have a problem sorting the white alloys, aside from silver, you can use AR to eliminate the base metals. I'd be happy to post the procedure I used if anyone is interested. Not worth the trouble otherwise. 

Dental gold is the jackpot for refiners. I know of no source that exceeds it in quality, not unless you have a good source of placer gold. You get not only gold, but silver, platinum and palladium. The gold alloy tends to run at least 16 K and can be as high as nearly pure, although that's unusual these days. It was once commonly used for impact fillings, similar to silver amalgam, but made of impacted gold foil. 

I certainly endorse heating---especially with the diseases that are rampant today---not just AIDS, but HEP C and others that can make your life miserable and short. If in doubt, do it in a fume hood, or out of doors with a breeze at your side. If you see white plumes coming from the gold crowns, good chance it's mercury. You don't understand the meaning of stink until you've worked with dental wastes. It's horrible. Good source of values, though! :lol: 

Harold


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## Lou (Mar 6, 2008)

Harold, please do post up a procedure. I too am interested in accumulating and processing dental wastes, along with other medical wastes.

I would like to see how you did it.


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## starzfan0211 (Mar 6, 2008)

Actually, I am probably just going to save the dental scrap up and send to Midwest. I have more than enough electronic stuff to work on and figure that is a way to kind of juice the cash flow a little with minimum hassle.


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## Harold_V (Mar 6, 2008)

Lou said:


> Harold, please do post up a procedure. I too am interested in accumulating and processing dental wastes, along with other medical wastes.
> 
> I would like to see how you did it.


Only on one occasion did I pursue the method, because of the sheer number of items included, and lack of time to be able to sort by hand. 

This is nothing that you wouldn't already be aware of, Lou. A basic dissolve and precipitate procedure, using only submitted material. The purpose is to reduce the amount of base metal so cleaner values can be precipitated. 

After roasting all the items, and mechanically removing all teeth (hammer on an anvil of sorts), all of the items were combined in one vessel, to which I added a limited amount of AR & (tap) water. There is immediate action as the lot is heated. When action ceases, I insure that all the nitric is consumed by adding a trace of HCl. The material is boiled at a low heat, and observed. The remaining base metals slowly precipitate all of the values, reducing themselves in volume. When the solution tests barren, it is dilluted with tap water, and allowed to settle well, decanted, then the process is repeated. It's obvious when values are present (by color), although testing with stannous should be routine, to insure there are no losses. The solution, when barren, shifts from a dark brown color to blue/green color. 

As the base metals are consumed, the solution will take longer to shift color, so the operation should be taken in small increments. That insures that the base metals can be eliminated instead of accumulated in solution. The final process will have dissolved all of the values, leaving only a small amount of base metal to be included. 

The procedure is time consuming, but requires almost no attention, so it's a good way to eliminate the bulk of base metals instead of hand sorting. It has no other redeeming qualities, near as I could tell, aside from not removing the platinum group prematurely. When enough is present, it can be recovered directly after precipitating the gold. My logic is that gold is far easier to wash than the salts of the platinum group, plus gold is generally the predominant value. 

Great care should be exercised when decanting, considering the values that are precipitated are simply tiny particles of black material and easily transfered when decanting. 

I avoided including any amalgam. The tin that is found in amalgam complicates filtration, as you know. If, by chance, any is included, if the material is well oxidized prior to dissolution, my experience in handling amalgam indicates that you can improve filtration procedures immensely. I always oxidized amalgam after it was removed from the retort for that reason. 

For the record, my normal procedure for processing dental waste was to inquart, after hand sorting. The majority of dental gold (that I experienced) was yellow, not white, and little of what was white was platinum or palladium, most of it being high temperature alloy, with no values included. I wanted to eliminate as much of the platinum group from the gold as I could, because of drag down. Palladium, when mixed with gold, is a particularly tough one to eliminate on the first refining. Considerable drag down is experienced, and it does not wash out well. It's presence is quite evident by the dark color of the gold powder, even after prolonged washing. 

Inquartation removes the vast majority of the platinum metals when you use silver, which I did. Because it enables platinum to dissolve in only nitric, even that is almost totally eliminated in the initial process. Silver becomes an excellent carrier of those metals, and concentrates them such that you can effect a good recovery when the slimes from the silver cell are processed. 

Rarely will traces of either platinum or palladium precipitate from solutions, and it's not worth the effort to evaporate to concentrate the solutions so they will. Nothing is lost---it is simply stored for the future. 

I'd enjoy reading your comments, Lou. They need not be complimentary----just factual. This is a good opportunity for readers to learn a process that is normally discouraged, but can be used to great advantage under the right circumstances. All pitfalls should be discussed. 

Harold


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