# Smelting,melting and incinerating



## Anonymous (Nov 15, 2010)

4metals suggested I start this thread to clarify some misuse of terminolgy,and to give and get help on this confusing subject.
Incinerating:Burning off exterior contaminents and preparing material to be processed via acids.
Smelting:Seperating,fully or partially,metals while in molten state.
Melting:Melting everything together in one conglomeration.

What I want to do is,prep my material by removing the excess steel,plastics,copper,aluminum...you get the idea,then melt everything with a lot of flux to remove/reduce the percentage of base metals.I am scared of values being digested by the flux.I am capable of doing this in a kiln/furnace for low air exchange,for minimal value loss.
I would love to build my own (larger) propane furnace,but would need help.I can do it on a smaller scale with good efficiency,however I have access to large drums,pipes,tanks...etc,and I have quite a bit of propane available and quite a bit of material.Our new house had a 120 gallon propane tank almost full :mrgreen: !


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## HAuCl4 (Nov 15, 2010)

If it weren't for dealing with the toxic fumes this would be very simple. As simple as a large crucible in a large furnace to produce a copper rich button containing all the values.


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## Anonymous (Nov 15, 2010)

I can make an afterburner out of a (bbq sized) propane tank.


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## HAuCl4 (Nov 15, 2010)

If you can really keep control of the fumes, that's your project finished. A large furnace with a large crucible to make a copper button containing all the values. Then sell the copper button. The fumes from those boards are very, very, very nasty. Maybe someone else has seen a system to process the fumes and will post. I doubt you can control the fumes easily with just a homemade after burner. Maybe something to condense the fumes will work?. I really don't know. Wait for 4metals!. 8)

If the copper button is very rich, you maybe can process it yourself too. :idea:

Do you know how much gold and silver you have per ton of boards to burn approximately?. If it is too low, this may not be profitable.


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## Anonymous (Nov 15, 2010)

At most I may have 1/2 ton of material right now.But the yield should be pretty good.Most of it is nasa related material.
I would rather make a condensor than an afterburner anyways.It would be much faster,less expensive to build and less expensive to operate/mantain.


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## HAuCl4 (Nov 15, 2010)

Unless it is a pretty rich half a ton, it is going to be hard to justify the costs of building everything. Now if you have more material coming that's different. Grab a piece of paper and a pen and throw some figures to make sure. For that size you don't need a huge furnace, maybe you have an old furnace lying around that you can use?.

Check with GSP too. You may be better off leaching this stuff with cyanide in a rolling drum. 500 Kg is not much. :idea:


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## Anonymous (Nov 15, 2010)

How about the bottom half of this? And I have a kiln top that would fit nicely over it. 



Images deleted


Also I'd love to do a Cn leach I know a gentleman that can get some for me,but I'll have to get a little more money first.I think it would work better than anything on my CPU powder from my ball mill.RIght now I have the biggest darn mess.The CPU powder is another reason I want to build the furnace.


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## HAuCl4 (Nov 15, 2010)

You do have a crusher no?. Make a small experiment crushing some boards to dust size and leach them in a cyanide tank. Perhaps you need not burn anything. GSP is the expert in this area. He has several old posts on the process.


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## Anonymous (Nov 15, 2010)

Yeh I have read many of them,and I read some info on an excellent website,however I am still scared,considering it's something I've never done before.


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## HAuCl4 (Nov 15, 2010)

Well I'm not trying to sell you on any process or idea. But burning those boards now seems like a bad idea to me, and the amount does not justify the expense on new equipment. Properly used, cyanide is very safe in comparison. Maybe some other safer type of leaching would work?. Your crushed boards would be treated like ore from a mine. A.K. Williams had several methods of leaching in his website. :idea:


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## 4metals (Nov 15, 2010)

The biggest cost of building an incinerator is the burners and controls but for a small one I would think it could be done using manual temperature control by turning on and off the burner. The home made burners I've seen on the backyard casting website should work. 

Incineration is never done in a crucible, it is either done on the surface of the incinerator refractory floor (which is fine if it's your incinerator) or in steel trays. The material has to be burned in thin layers and usually it has to be raked. 

I think an ideal body for the incinerator could be a vogelzang double barrel stove kit. The kits are cheap and made to use 55 or 30 gallon drums. This is a single drum kit http://www.2kstore.com/stove/stv6.htm if you start with a 30 gallon steel drum and pour a 3 inch refractory cement layer at the bottom, when it dries cut the hole for the exhaust to come out of, usually a 6" hole. Now insert a 14" or so sonitube as a form to pour the refractory wall and add small section of 6" sonitube to connect the hold you made to the inside chamber of the incinerator. Pour this with refractory cement and add some needles which are sold to stiffen the cement in incinerators and act as rebar. When it dries you will have the body of an incinerator. the door from the kit has to be installed into the front section which should also be refractory cement. Set the door so when it opens the bottom is flush with the refractory so you can rake out the burnt material. 

Now all you need to do is install one of those backyard casting burners in the door or even through a hole in the side so the flame hits on the material we are trying to burn. A thermometer sticking into the chamber can give you an idea of the inside temps. 

Now the second drum is for an afterburner, it goes on top of the first (both laying horizontally) and has a solid bottom as before, the same sides, and a solid top with a hole for another burner. The afterburner should run at 1500 to 1700 degrees to burn the smoke. Add a stack and you'll have a mini incinerator. 

Now controls and forced air feed burners are possible, and some on the forum may be able to advise us as to how to install these. 

This should produce burnt e-scrap, ready for crushing and sifting and melting the oversize with copper. The quantity of material you can load it up with is learned by trial and error. 

The products of this process should be homogeneous and easily assayable.


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## rusty (Nov 15, 2010)

This is my home made foundry furnace that now doubles for refining and incineration, propane fired using a roofers tar kettle torch

The roofers kettle torch uses liquid propane feed into a coil wrapped around the burner head to vaporize the liquid into vapor, the real advantage of using a liquid fired torch is that you do not get frost on your supply tank. The flame you start out with is constant until all the fuel has been consumed and it's hot around 800,000 BTU's.

The furnace is lined with 4" of refractory with a cerwool liner, the furnace after running for hours on end is cool to the touch on the outer shell, I have used this furnace for the past five years the first two almost daily casting my aluminum fishing weight molds which sold on ebay.

To build the furnace I used an old bladder tank from a domestic water system, poured the floor first then inserted a plastic garbage pail fill with sand to pour the shell. The cerwool is self explanatory. 

The lid has spikes installed before pouring the refractory to hold everything in place, the lid is a bit heavy but I usually have the furnace sitting under a hoist on a trolley.

There are a number of options available to fire the furnace, you can use propane, natural gas if your gas supplier is willing to install a high pressure meter, waste oil, charcoal or coal.

Having the high pressure natural gas meter installed entails some expense plus you need to throttle back the pressure on your home appliances.

First picture is one of my castings, second picture is incinerated IC's, the rest are of the furnace.


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## 4metals (Nov 15, 2010)

The reason for firing e-scrap in an enclosed chamber incinerator is the air velocity the burning material sees. The dust can be more valuable than the meltable metallics and blowing into a small melter style furnace will send the dust flying. I have seen units like Gill's used as after burners, just run the smoke in the bottom and out the top. 

Based on the air flow through the incinerator you can determine the time needed to keep the smoky air in the after burner and design one long enough to give the required retention time. 

The roofers kettle torch makes for a nice hot flame.


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## Anonymous (Nov 15, 2010)

Then my tank should work perfectly.All I need is to make sure the lid I have will fit.Then I will need containers to incinerate,then back in the ball mill,then I need a crucible and a lid for melting.
Well I will certainly need more money,my friend sent me over 100 pounds of "pre"processed cpus,and they are grinding great.I am using a window screen for sifting the powder and it's working very well.Everything that doesn't make it through the screen gets thrown back in,with more cpu's,for more grinding.I am running them in AR and Im getting a HUGE mess.It's working but its a pain in the butt.Oh yeh and I am getting purple on the bottom of my flasks.I believe it is precipitated gold.Here look for yourselves.
Images deleted
It is a very deep purple color and right on the bottom,very difficult to get it to move.When I stir up the mixture that purple stuff is the first stuff to drop,my only guess is gold


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## rusty (Nov 15, 2010)

After milling the chips wet and screening, I give the powders recovered a hot HCL bath, filter then the powders go into incineration to kill off the HCL because the next move is to go after the silver and any palladium that maybe present from here I can go straight to AR with out killing the nitric to get the gold out.

Right now I'm using my wood heater in the shop to incinerate, I wait until I have a nice bed of coals then put my containers inside then cover them with a stainless steel sheet before loading the heater up with more wood.

You could do the same thing using briquettes.

I think that your purple maybe tin.


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## Anonymous (Nov 15, 2010)

The solutions were testing negative,I added a little more nitric with noticed no response,until I stirred it.Then the stereotypical ploom of red and then it tested positive,I looked on the bottom and the purple was gone.I can't explain why it did that,all I know is what happened.
Also I mill my chips dry,when I create a better screener,I will start running them wet.

Thanks gill for helping me with this,and thank you again for posting your mill,I admired it from the first time I saw it some time back.I think you have a gift,and I wish I had the same gift.I am more than capable of getting things done,but you surely have a knack and talent for making stuff very well.Unfortunately time is always against me,we usually need money on a day to day basis,so I usually do not have a lot of excess time,hence my desire to have others help me in this venture with the furnace.
Thanks again.


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## rusty (Nov 15, 2010)

mic said:


> The solutions were testing negative,I added a little more nitric with noticed no response,until I stirred it.Then the stereotypical ploom of red and then it tested positive,I looked on the bottom and the purple was gone.I can't explain why it did that,all I know is what happened.
> Also I mill my chips dry,when I create a better screener,I will start running them wet.
> 
> Thanks gill for helping me with this,and thank you again for posting your mill,I admired it from the first time I saw it some time back.I think you have a gift,and I wish I had the same gift.I am more than capable of getting things done,but you surely have a knack and talent for making stuff very well.Unfortunately time is always against me,we usually need money on a day to day basis,so I usually do not have a lot of excess time,hence my desire to have others help me in this venture with the furnace.
> Thanks again.



This may surprise some but my refractory didn't cost me a dime, and I had enough to give to a friend when we moved to Manitoba 4 years ago.

These good folks Fairy and Company in Delta B.C. had a pallet load of high temperature cast-able refractory in torn or broken sacks which I got for free just for hauling it away saving them tipping fees.

Fairy and Company in British Columbia http://www.faireyco.com/

Pick up the telephone and make a few calls to the local foundry supply folks you just never know what you'll ferret out. If you feel guilty bring the manager an ounce of silver chances are he is into casting jewelery or has a special customer that he would pass it over too.


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## Anonymous (Nov 15, 2010)

rusty said:


> Pick up the telephone and make a few calls to the local foundry supply folks you just never know what you'll ferret out.


Thats a heck of a good idea.I'll start searching in the morning.


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## rusty (Nov 16, 2010)

mic said:


> rusty said:
> 
> 
> > Pick up the telephone and make a few calls to the local foundry supply folks you just never know what you'll ferret out.
> ...



Good luck in locating damaged bags of refractory. and why are you not wearing gloves while working with your acids. Lets try to set a good example here get some chemical gloves.

Milling those chips dry is not a good idea that dust is going to take a toll on your health.


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## Anonymous (Nov 16, 2010)

Thanks to my gloves I almost dropped one of my 4000ml erlenmyers,I took that one off so I could hold the flask up high enough for the picture safely,as far as the dust goes,my room is VERY well ventilated,however I may be getting trace amounts of dust in me,not to mention any values I am losing,hence the reason I want to set up a better screening system,so I can run wet.I appreciate your concern,however I am the LAST person you need to worry about being safe.


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## HAuCl4 (Nov 16, 2010)

Interesting photos and tips guys. 8)


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## 4metals (Nov 16, 2010)

Years ago I used one of these to burn in http://www.small-incinerators.com/portableincinerators/smartash/gallery/ they were called burn down cans. For e-scrap you would need kerosene or some fuel to get it going, or possibly balled up newspaper with circuits in the middle.


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## Oz (Nov 16, 2010)

Now that is real interesting! Do these meet EPA requirements when burning circuit boards? If they will take diesel as a fuel I would bet waste oil or used vegetable oil would also work.


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## Anonymous (Nov 16, 2010)

Not so sure I would use one for pcb's oz,theres an aweful lot of air transfer there.Maybe a partially sealed container inside the drum would work well,that would slowly introduce the smoke to the fire.I am thinking that would work pretty well.

I am sure that model "Drug Terminator" will end up angering some members on the forum though.....


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## 4metals (Nov 17, 2010)

I used them for burning Kim Wipes which had gold paste on them from hybrid manufacturers. I've seen them used for some nasty stuff though.


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## goldsilverpro (Nov 17, 2010)

4metals said:


> I used them for burning Kim Wipes which had gold paste on them from hybrid manufacturers. I've seen them used for some nasty stuff though.


That is very interesting. What is the cost?


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## 4metals (Nov 17, 2010)

I bought them in the '80's and they were about $400 for the unit, you supply the drum. They used to be called trash aways but I can't find any listings now under that name.


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## glondor (Jan 12, 2011)

I just priced one of these, Smart ash. They wanted 5 grand and would not sell me one because I live in Ontario. Way too much money and bullsh1t. http://www.small-incinerators.com/portableincinerators/smartash/gallery/

I really want to be able to incinerate this stuff. I was thinking of an 8 inch steel tube inside one of these barrel burners with a smallish vent hole in a lid on the tube. Almost a roasting. Would this be a reducing atmosphere? If so would this be an asset or a drawback? Any one know?


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## skippy (Jan 12, 2011)

I'm not an expert, but I would say reducing atmosphere is a drawback. You'd have a much greater quantity of nasty complex chemicals making it through. Polycyclic aromatic hydrocarbons, halogenated hydrocarbons, dioxins etc. A reducing atmosphere would be ok in a first chamber, if followed by reburning the carbon rich exhaust in an afterburner. Even post afterburner the dioxins can reform unless the gasses drop a certain temperature range very quickly. 
Then there is still HCl and HBr in the exhaust from burning the PVC and brominated flame retardants. This needs to be scrubbed out. 

Making your own incinerator to match the function of a commercial one capable of handling e-scrap withing emissions regulations is no small design challenge.


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## waltsplaza (Jan 27, 2011)

I was just wondering if graphite gold ingot molds require any pre-heating before making a pour?
Thanks, Walt


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## Harold_V (Jan 28, 2011)

waltsplaza said:


> I was just wondering if graphite gold ingot molds require any pre-heating before making a pour?
> Thanks, Walt


Gold should NEVER be poured to a cold mold, regardless of its construction. Should the mold have any moisture, you risk a steam explosion. Hot flying gold can prove quite hazardous, to say nothing of being costly. A good rule of thumb is to blacken a mold and heat it just below the point where carbon combusts, then make the pour. You can improve surface finish of the ingot by proper blackening of the mold, but it's very important when pouring to an iron mold, which I recommend over graphite.

Harold

Edit: Moisture in a mold isn't always obvious. A mold can appear dry and still have enough moisture to cause the explosion. Be certain to preheat your molds.


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## bubba (Oct 15, 2011)

4metals said:


> The biggest cost of building an incinerator is the burners and controls but for a small one I would think it could be done using manual temperature control by turning on and off the burner. The home made burners I've seen on the backyard casting website should work.
> 
> Incineration is never done in a crucible, it is either done on the surface of the incinerator refractory floor (which is fine if it's your incinerator) or in steel trays. The material has to be burned in thin layers and usually it has to be raked.
> 
> ...




This thread is quite interesting, has anyone who has done this know how much the e-scrap (boards,etc.) is reduced by incineration? I am talking by weight.....30% ?, 50 % ?, maybe more?.......


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## goldsilverpro (Oct 15, 2011)

> This thread is quite interesting, has anyone who has done this know how much the e-scrap (boards,etc.) is reduced by incineration? I am talking by weight.....30% ?, 50 % ?, maybe more?.......



It's been a long time and I really didn't worry about those kind of numbers when I did circuit boards - what it was was what it was. Also, the material has changed, somewhat. Before burning, we removed most of the big stuff, like transformers, aluminum heat sinks, and steel (and, often, the larger electrolytic tantalum capacitors, if there were a lot of them - in the 80s, you might find 1/2# of them on a board - they were heavy and fairly valuable and added up quick - if we had burned them, we would have lost all their value). Then, from what was left, I think about 65-75% of the weight, on average, was eliminated by burning to white ash.


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## bubba (Oct 15, 2011)

goldsilverpro said:


> > This thread is quite interesting, has anyone who has done this know how much the e-scrap (boards,etc.) is reduced by incineration? I am talking by weight.....30% ?, 50 % ?, maybe more?.......
> 
> 
> 
> It's been a long time and I really didn't worry about those kind of numbers when I did circuit boards - what it was was what it was. Also, the material has changed, somewhat. Before burning, we removed most of the big stuff, like transformers, aluminum heat sinks, and steel (and, often, the larger electrolytic tantalum capacitors, if there were a lot of them - in the 80s, you might find 1/2# of them on a board - they were heavy and fairly valuable and added up quick - if we had burned them, we would have lost all their value). Then, from what was left, I think about 65-75% of the weight, on average, was eliminated by burning to white ash.



thanks. I have been trying to find the time to go through your book,just got it last week, lots of good info. thanks again. andrew.


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