Precious Metal Refining & Recovery, Episode 17: Teeth

[Music] fighters welcome back to Cody's lab so it's been a year now since I started my precious metal refining series and also it's been a while since I've done the last episode so I figured I'd suck that up again and process these gold teeth so these are some gold crowns that were taken out of actual people's mouths as you can see this crown used to go on top of a molar and they've been removed and now they are scrap gold it should be around 18 carats and it mixed with various other metals to make it harder and today I'm going to be processing it down and separating those metals so that this is a pure gold bullion I have everything here that I need to perform the task now for the people who are newer to the series I'm going to go through this and explain what each of these are in order to find the gold I first must dissolve it now gold is very resistant to chemical attack as you might know and so the only thing that can really dissolve it is strong mineral acids so I have here some muriatic acid and some spirit of knitter otherwise known as nitric acid so see 35% hydrochloric 75% nitric acid I'm also going to need various chemicals to selectively bring the metals back into a solid state in this case I have aa Kosilek acid for the gold reduction and dimethyl gwak's amine for the blade IAM reduction but i'll talk more about these later for now I've got two beakers here of the acids measured out you've got 40 milliliters of nitric and 100 milliliters of hydrochloric that's a approx amount I'm going to need I'm going to add the nitric slowly as it is consumed in side reactions I've also got a large beaker here to perform the reactions in I also have some gloves and safety goggles which is a pretty good idea to use especially if you don't like the idea of getting corrosive chemicals on your skin me personally I don't mind it so much but yes now over here I have a scale that is of course to weigh the materials to see what we have to begin with what we have after that way we can determine you know if we lost something along the way so measuring up those teeth looks like just under 25 grams total here I'm considering that's 18 carats that means I probably got set well about 18 grams of gold so that should be about what I'm expecting which is quite a significant amount I think is actually more than I've ever done it once it ending one time I have a hot plate here now this is to warm the reactions and speed it up it's not strictly necessary but it will save literally days I've got a pan here with some gravel this is to dissipate the heat so I don't break my glass bonus points you know where this gravel came from and of course I'm going to need a way to melt the metal so I get a little furnace here they can get up to 2,000 degrees Fahrenheit a little melting dish to melt the stuff in and of course tongs to get it in and out of the furnace so I think that should be just about everything let's get started first of all I took a small piece of the gold and I put it inside of this flask here with some aqua Riga mixed up operator of course is the mixture of these two acids now the idea here to see if importation is necessary you see if there's too much silver here the Aqua Riga would not dissolve it which would be a problem and it looks to me like it dissolves it without trouble so we're going to go ahead and just put these things in without the importation process if the silver concentration is too high it'll form a protective layer that will keep the metals from dissolving this the silver is low enough then it'll just kind of flake off as silver chloride in the metals will completely dissolve of course I only tested one of the teeth so it may be possible that a few of them have too much silver in which case I will need to melt them down with another base metals such as copper let's add my hydrochloric acid just like this that clean them up nice lift I'm going to add half of my nitric there about that I'll add half later look right now let's get that on the burner that's warming up to increase the speed of the reaction and of course I forgot to put my gloves and safety glasses on I'm going to do that now I mean the real dangers are going to be when it starts out boiling and popping so it's not too bad alright so for the time-lapse camera you guys can watch that dissolve I'll kind of hang around watching it but not too close because it does produce toxic fumes you'll also notice I'm outside here so the wind can blow everything away and yeah come back in a few hours and see if that's actually devolved in this gold dissolving process the nitric acid oxidizes a thin layer of gold the hydrochloric acid is then able to react with that oxidized layer forming armed chloric acid which is water-soluble once the hydrochloric acid is stripped off the oxide layer the nitric acid is free to oxidize the gold once again and the process continues until the pieces are completely dissolved so after dissolving all night long I'm left with some peat still I thought this might happen this kind of means that they weren't as high of carat as I was told they were but let's see how much is left I think a couple of them did to actually dissolve yeah I'm left with 18 grams I mean 5 7 grams of gold was actually dissolved which I have over in that little beaker right now which means I am going to have to import this to get it to finish dissolving and for that I've got some silver powder here just some stuff that I had on hand I'm going to put these teeth inside of the crucible I'm going to add roughly an ounce or two of silver and then put them in the furnace and melt it down making an alloy of the silver and gold that is mostly silver okay there we are I'm just going to take this to pour it into some water so it breaks up the metal into little beef nice little around discs which is perfect is that will dissolve in the acid quickly hopefully this is less than 20 percent gold by weight so with a real dissolve in the acid so I'm going to add a bunch of distilled water this is so that we can keep the silver nitrate soluble I'm going to add a little bit of nitric acid now the nitric acid will dissolve the silver again it won't dissolve the gold gold will be left behind as a find brown or black powder which should be nearly pure and I can take that and dissolve it aqua Riga hopefully the nitric acid is digested the silver out let's pour off the solution look at the color of that yeah it's definitely got some play diem in there so definitely keep this solution I mean it was anyway because it's got mostly silver nitrate well motion that off and there is our material which should be mostly gold and anything else that involve in the nitric acid such as platinum let's look at this SD it's very crumbly well the silvers been dissolved out of it so now you've left with basically the sponge-like material now I'm going to add in just a little bit more nitric acid and see if I get any reaction looking like I'm not getting a reaction that means I got all the silver out excellent for the rest of this 20 milliliters in there and then go find the hydrochloric acid let's make a curry go again dissolve that gold so I just added the hydrochloric acid as you can see it kind of clouded up in there because I didn't get all the silver nitrate out but that's alright not very much silver in there and it's certainly not stopping it from reacting with the gold as you can see it's beginning reaction already let's leave this on the hot plate put on my watch glass there fan and I'll come back a little while in the salt at all the reaction is stopped and I'm left with gold dissolved in the solution and a little bit of a silver chloride that is masked get in there is contamination but how but you need to separate out I'm just going to pour this do another glass dish and it still doesn't matter if I get a little silver in there this is just to get rid of the leftover nitric acid so there's that one and here's the gold that was dissolved earlier it's probably green gave us some copper and again I will be getting rid of those contaminants in a little while well this continues to evaporate down let's go deal with this and see if we can separate the palladium from the silver first of all let's get it out of the jam jar so that we can work with a little bit better I'm going to pour it off into the speaker making sure not to pour off anything that is filled to the bottom yeah a little bit of silver in there okay I'm going to take this and go warm it up in addition to this beaker I also warmed up some distilled water which I will be dissolving some dimethyl glocks amine into you see here the stuff is not particularly soluble but it will dissolve in warm water now to stir this in it gives much of it for the dissolve of the can now pour this into the silver and palladium solution now the caladium should form a nice yellow precipitate which you can already see forming excellent the stir so there is a lot of palladium here so much that I'm having to resort to filtration to get it all out of the solution there you a little bit settle to the bottom there but you can see that the solution that is coming out of the filter the filtrate is a light bluish green color which means I've got all the Palladium out of it and what I'm left with is some silver nitrate and a little bit of copper I can just easily extract the silver by adding some core ID of some sort dropping the silver out of silver chloride which I'll recycle into using has more in quotation material we drink this with distilled water a few times to get out all the silver silt in the filter paper up and see what I've got here that and I've got more left in the gold solution excellent so here is our gold solution over the last two days I put this evaporate down slowly I've added more hydrochloric acid and evaporated it down again all in an effort to get rid of all nitric acid that may be present and now I'm going to put it over this taller beaker like this now that the silver has had a chance to settle down let's put it back over into this large dish there's the silver minute rinse this with a little bit more water now that I have this solution warmed up again I'm going to add 20 grams of oxalic acid which I just mixed up with some water and this should reduce the gold yes I can already begin seeing the reaction excellent you see how it's getting all cloudy okay now that's in and give it a bit of a stir and I'm going to slowly add sodium hydroxide to lower the pH and more effectively produce the gold yeah oh and look how shiny and I hope I hope you can feel on the camera that looks like it's got glitter doesn't look like I really need the sodium hydroxide I'll just let this continue then we should have some gold [Music] like the reaction is stopped so now I'm going to pour off the liquid into this other colored glass like and let it finish settling and yes I do believe this is the first time I've used a funnel at least in quite a while pour this out as my gold sponge so here's the gold and here's the leftover solution which could contain platinum and palladium check for platinum I'm going to put in a pinch of ammonium chloride this Platinum's there I should get a yellow-orange precipitant judging by that reaction I'd say there's either not platinum or very little let's skip the Platinum and go straight to extracting the Palladium putting in a little bit of dimethyl luxe mean that gets the result definitely has palladium there's my palladium and there's my gold you put the gold over here in this melting dish so we can put it in the furnace which I will do right now there it is that cool off I'm away put this goal on the scale see just how much we've got looks like just under 15 grams it's not a bad recovery you know in expecting 18 grams but I think that was because the gold that I had was not the 18 karats that I was told it was it was probably closer to 14 carats for the stuff that didn't resolve in the acid I still work on the palladium I now have my palladium dissolved in the lid and now I'm going to put it back in the furnace and smelt the lead away and pull I'm left with just the Palladium still going to be impure still going to have quite a bit of lead in it but I have a way I can get rid of that see the problem is I'm not getting it hot enough with this furnace because when you melt it well 3000 for a night and if you're getting it 2000 so let's try this other torch here I'm going to hit this bead with my hockey mat gas torch and hopefully this will get hot enough to actually melt the Palladium come on oh no problem they're oxidizing flame to burn out the rest of the leg I got a nice looking bead okay turn off the oxygen and just before it completely cools I'm going to blast it a little bit of yeah just keep the bead looking nice put this little bit of palladium on the scale and see it we got just over half a gram that's rather pitiful but there it is measure cover the Palladium out of both teeth so out of 25 grams of teeth we got 15 and a half grams worth of precious metals that's not including the silver imagine the silver was the bulk of the rest of it yeah kind of gives you an idea of how much is actually in them there's the pieces and a little bit better lighting you see the gold there and the palladium yeah has it pretty made some teeth I guess the question on everybody's mind right now is what happened to the light so I guess the question on everybody's mind right now is could I actually make money doing this and well let's go over that I bought most of the teeth on eBay and I averaged about $22 per gram of the auctions that I want however a lot of the teeth that I got were from fans donating them so I didn't pay anything for them really but assuming that I did have to buy them for the average $22 per gram that means that for the 25 grams of teeth by page right around five hundred and fifty dollars for them all now this is 15 grams of gold about half a gram of palladium that works out to maybe six hundred and ten dollars so there is a small profit margin that is possible but with all the chemicals and stuff and certainly my time you might be able to do it if you could buy pounds of teeth and you know scale up your production process but other than that you're not going to make money off of these so hope you all enjoyed we'll see you next time

Channel: Cody'sLab

Views: 1,025,588

Keywords: gold crown, chemistry, how to, dimethylglyoxime, oxalic acid, nitric acid, acid, aqua regia, silver, inquartation

Id: W3bkIkIKKEs

Length: 18min 19sec (1099 seconds)

Published: Fri Feb 17 2017