# Rotary Furnace - Anyone seen a small one? Pictures? Etc.



## snoman701 (Nov 26, 2017)

I'm looking for an example of a rotary furnace. In a perfect world I'd have a few of them. One for small melts, say 5 lbs and under, another 10-20 lbs, another that is a 40 lb melt.

For smelting copper and silver. 

I do NOT want a side tap. I want a tilting crucible. 

I'm having the most difficulty with refractory. My refractory supplier does not know of any pourable or rammable refractories that will hold up to the corrosive nature of fluxes. And we both know "hold up" to be a relative term. I have a lead on a haberson walker product, but have to call the rep tomorrow. Then find it in bag quantity instead of pallet quantity (the hard part)

Actually, for the small furnaces, I'll probably just use a standard silicon carbide crucible, held by a fabricated inconel cage that is hooked up to a gear motor, tilted just a tiny bit.


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## eastky2 (Nov 26, 2017)

Why would you a furnace that just tilts a little? With that little tilt as soon as the flux becomes molten and can start to flow you will be losing heat.

I think you are putting the cart before the horse.


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## snoman701 (Nov 26, 2017)

eastky2 said:


> Why would you a furnace that just tilts a little? With that little tilt as soon as the flux becomes molten and can start to flow you will be losing heat.
> 
> I think you are putting the cart before the horse.



I want a furnace that has a little tilt as it increases surface area contact of the melt (flux or molten metal) and will thus increase the mixing. When it's time to pour, then it's tilted the rest of the way. 

Industrially, this is done in a horizontal furnace with blow through flame and a cap on each end. Either the cap is removed prior to pour, or there is a center tap. I do not want a center tap. I've just never seen a version of this that melts less than say 500 lbs at a time. 

There is no horse or cart. I need to be able to (s)melt, mix (while melted), sample and pour copper ingots. I want a furnace that mixes well so I can effectively flux off zinc from brass without standing there with a graphite rod trying to mix it.


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## Shark (Nov 26, 2017)

I have been looking for a long time for something similar. The uses would be well varied and worth the trouble. Are you looking for a design, the refractory or both? I haven't really found a design on a small scale, but some of the bigger ones could be reduced I would think. I talked to a company rep from my area a while back and he had ideas on the refractory to use for a small rotary furnace I had in mind that was about the size of 30 gallon drum. I would have to get back with him for the name as it slips my mind right now. The only job this guy has ever had was lining or relining commercial furnaces.


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## snoman701 (Nov 26, 2017)

Shark said:


> I have been looking for a long time for something similar. The uses would be well varied and worth the trouble. Are you looking for a design, the refractory or both? I haven't really found a design on a small scale, but some of the bigger ones could be reduced I would think. I talked to a company rep from my area a while back and he had ideas on the refractory to use for a small rotary furnace I had in mind that was about the size of 30 gallon drum. I would have to get back with him for the name as it slips my mind right now. The only job this guy has ever had was lining or relining commercial furnaces.



That's why I was so confused by the refractory companies lack of knowledge, as that's what they do as well. BUT...if it's anything like glass furnaces, you have to know your refractories, but you just order the crucible. But even with that, patches are routinely applied and such. So I am looking for the refractory. 

But I'm also looking for experience more than anything...I'll be building my own, and was hoping to get others experience in design / operation to skip the learning curve. I'm used to building V0.1, V0.2, and so on, until I'm done building...I'd really like to skip forward to a furnace that I don't want to turn around and rebuild instantly...that is, until I'm in a facility that allows me to set up an induction power supply. 

I've built plenty of kilns, furnaces, forges and such...so all the other parts are simple. I've been playing with fire since I was a wee little one.


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## snoman701 (Nov 26, 2017)

Shark said:


> I have been looking for a long time for something similar. The uses would be well varied and worth the trouble. Are you looking for a design, the refractory or both? I haven't really found a design on a small scale, but some of the bigger ones could be reduced I would think. I talked to a company rep from my area a while back and he had ideas on the refractory to use for a small rotary furnace I had in mind that was about the size of 30 gallon drum. I would have to get back with him for the name as it slips my mind right now. The only job this guy has ever had was lining or relining commercial furnaces.



And yes, there are TONS of uses for one.

If I've got my energy tomorrow I'll run to the refractory store and talk to him face to face. I need some fiber board anyway.


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## eastky2 (Nov 27, 2017)

snoman701 said:


> eastky2 said:
> 
> 
> > Why would you a furnace that just tilts a little? With that little tilt as soon as the flux becomes molten and can start to flow you will be losing heat.
> ...



If you were a really enterprising person. You wouldn't worry about burning off the zinc.

Why don't you hit some flea markets and buy some small designer items that you could recast with yellow brass that would sell for more than scrap price ?


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## Shark (Nov 27, 2017)

I can't speak for Snoman, but I am using the copper as a collector metal. Among some of those things that could be collected are the different types of pins. When smelting some metals it is best to remove as many of the unneeded base metals as possible. Nickle being a prime concern, the fewer base metals being poured along with your anodes the better. These should make it a bit more clear than I can...

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=38&t=23680#p249793

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=86&t=24397#p258067


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## eastky2 (Nov 27, 2017)

Shark said:


> I can't speak for Snoman, but I am using the copper as a collector metal. Among some of those things that could be collected are the different types of pins. When smelting some metals it is best to remove as many of the unneeded base metals as possible. Nickle being a prime concern, the fewer base metals being poured along with your anodes the better. These should make it a bit more clear than I can...
> 
> http://goldrefiningforum.com/phpBB3/viewtopic.php?f=38&t=23680#p249793
> 
> http://goldrefiningforum.com/phpBB3/viewtopic.php?f=86&t=24397#p258067



Shark

In Snomans reply to me he was wanting to remove the zinc from brass. 

4metals is a very giving person on this forum. I respect 4 metals. When I read 4metals post on this forum I can understand what he is talking about. 

People need to understand that every person is not capable of achieving the same out come.

Not to hurt feelings but Snoman is a braggart. He talks a lot of gibberish on this forum. He makes no sense sometimes.


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## snoman701 (Nov 27, 2017)

eastky2 said:


> Shark said:
> 
> 
> > I can't speak for Snoman, but I am using the copper as a collector metal. Among some of those things that could be collected are the different types of pins. When smelting some metals it is best to remove as many of the unneeded base metals as possible. Nickle being a prime concern, the fewer base metals being poured along with your anodes the better. These should make it a bit more clear than I can...
> ...



To clarify, yes, this is to pour copper anodes from BRASS gold plated pins...not trinkets to be sold at a flea market. 

And further, there's a heck of a lot of uses for a tumbling furnace BEYOND casting anodes. I'm glad Shark recognizes that. 

I do think that's the only time I've been accused of being a braggart. I have never realized I was bragging, and if I am, I apologize. I've tried to be appreciative of advice I'm given. I bust my butt, and I'm trying to find a niche in which I can make a living, without having a hundred grand in startup funds. So frankly, if you have issues with me spending my whole life concentrating on this, spending my time reading every post made by Lou, 4Metals, Anachronism, etc....I don't know what to offer other than my apologies. I ask questions relevant to my experiences and curiosities. You call my posts gibberish, but Shark sees value?

As for the specifics of bragging: 

I go out EVERY day except Sunday LOOKING for precious metals, be it e-scrap, industrial scrap, silver, etc. I buy every bit of it I can afford, and some I can't. I have made sacrifice after sacrifice for what I have. I bust my butt every time i have the opportunity to learn from someone. Tomorrow is a perfect example...I will go and shovel hydroxide wastes for my gold buyer, in exchange I'll learn more about how to interpret XRF, beyond the numbers it spits out from it's built in algorithms. 

You wanna know what doesn't make sense? How very few people on this forum are really making their living doing this. Where's the startup stories? I can show them to you on machinists forums. On welders forums. In all kinds of trades. Guys that saved their money for their first piece of equipment, and busted their butts. Going from $50 and bills to pay to making a living, and practicing your trade lawfully, current as they are today. There's only a couple people on this forum that I know of that have done it...and they'll proudly tell you that. 

So here's mine:

I started buying material a year ago. For 12 months I put building inventory ahead of everything except my family. I'm in the green $6,000 this year and I'm darn proud of it. From starting with a little knowledge around silver, and having sold a few loads to boardsort five years ago...to a couple months of taking home a paycheck, and actually successfully working towards being able to maintain profitability. Starting with basically nothing. 

THAT IS AN ACCOMPLISHMENT. So yes, in that regard, I am a braggart, and I'm darn proud of how hard I've worked to get to this point.

People need to understand that every person IS indeed capable of achieving the same outcome if they put in the effort. That's called science.


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## snoman701 (Nov 27, 2017)

Shark said:


> I can't speak for Snoman, but I am using the copper as a collector metal. Among some of those things that could be collected are the different types of pins. When smelting some metals it is best to remove as many of the unneeded base metals as possible. Nickle being a prime concern, the fewer base metals being poured along with your anodes the better. These should make it a bit more clear than I can...
> 
> http://goldrefiningforum.com/phpBB3/viewtopic.php?f=38&t=23680#p249793
> 
> http://goldrefiningforum.com/phpBB3/viewtopic.php?f=86&t=24397#p258067



My goal with the furnace is not only the anodes, but being able to process ash with silver or copper as a collector.


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## Lou (Nov 28, 2017)

Why not just build one out of a stout cement mixer?

Reinforce the frame, get a much higher torque electric drive motor and worm drive gear box, and then get a large scarfing torch. Professional units have a water cooled torch so you can really get in there and blow the tramp out of the metal. The flame literally impinges in the melt. Rather than hydraulics, maybe get a chain hoist to raise and lower it, and put a button on it. If you want to go crazy, build an angle iron frame, but a tire on it which the furnace can spin upon and go from there. 

Put insulating brick (they come in geometries that you'll like that can make it cylindrical or octagonal). This brick can be cut wet with a simple wooden hacksaw. Ideally, you should never need to replace this. 

Get a high alumina refractory, as high as practical, like this:
http://www.mtsavage.com/LinkClick.aspx?fileticket=1sox8EMsf5k%3d&tabid=115&mid=572
Which is what I lined my tilting furnace with. It has stood up to soda ash and borax no problem. AVOID SILICA!! Zirconia also handles basic fusions and borax very very well. 

If you want to be extra sure about things, you can get silicon carbide brick to face the furnace with. Very hard to heat up and a devil to cut, but if you're smelting hundreds of pounds all day with aggressive mixtures, you'll not find better or more lasting. Otherwise, plan a rebrick schedule. Oh, and don't forget not to add your metal and such until the furnace is hot and the bricks have expanded together. Usually, at places with big horizontally fired rotary furnaces, they charge the furnace with borax at low fire to glaze the refractory, dump the smelted charge in, then more borax and top and move it around a bit to get the borax over the metallics. Then they turn up the burners.

While I've never personally built a top blown rotary converter, I've seen them in industry and have built some multi ton tilting furnaces that used refractory brick and that 3300 F castable and was not disappointed. One of them is a ~1 M BTU burner that would do about 500 lbs of sterling/hour quite reliably and was not noisy-- all this with the outside cool to the touch. 

Here's some videos outlining what I'm talking about:
https://www.youtube.com/watch?v=GYUJeNW7Bgc

or this:

https://www.youtube.com/watch?v=UqpkFcjKYOM

Running a lean O2/fuel flame, you can blow out lead, tin (with base in the flux, lime to give calcium stannate, but eating some refractory), zinc, and even oxidize copper. Blowing sterling like this can get it from nominally 90% to 992 fine silver for the cell. Reveb furnaces, like what 4metals has described, are also good at this but probably more stack loss of silver.


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## eastky2 (Nov 28, 2017)

In Snomans reply to me he was wanting to remove the zinc from brass. 

4metals is a very giving person on this forum. I respect 4 metals. When I read 4metals post on this forum I can understand what he is talking about. 

People need to understand that every person is not capable of achieving the same out come.

Not to hurt feelings but Snoman is a braggart. He talks a lot of gibberish on this forum. He makes no sense sometimes.[/quote]

To clarify, yes, this is to pour copper anodes from BRASS gold plated pins...

I never knew there was brass plated pins in escrap. Thanks for letting me know that.
I have never ran across that before. Can you post some pictures of some brass plated pins so everyone will be aware to collect them.

While you are out looking for precious metal scrap and thinking $6000.00 for a years worth of riding around and picking up scrap is worth your time and gas good luck to you.

While your out riding around and burning gas. I will be online buying scrap that is already broke down and 
earning money.



People need to understand that every person IS indeed capable of achieving the same outcome if they put in the effort. That's called science.[/quote]

Science is more or less based on theory. If it hasn't been proven its not science. I will say that even things 
that are reported to have been proven isn't science. The human mind is always in a evolving and learning
experience.


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## snoman701 (Nov 28, 2017)

Lou said:


> Why not just build one out of a stout cement mixer?
> 
> Reinforce the frame, get a much higher torque electric drive motor and worm drive gear box, and then get a large scarfing torch. Professional units have a water cooled torch so you can really get in there and blow the tramp out of the metal. The flame literally impinges in the melt. Rather than hydraulics, maybe get a chain hoist to raise and lower it, and put a button on it. If you want to go crazy, build an angle iron frame, but a tire on it which the furnace can spin upon and go from there.



So what you are saying is to buy a stout cement mixer, then throw everything out except the barrel! 

It is a good idea. I used to hand form cones out of stainless...and customers never complained when I charged 2x normal shop rate. It's hard to find places that can make good cone shapes for reasonable prices (and I don't have the equipment myself), so the cement mixer makes it that much more appealing. 

Thanks for the link on the refractory! I'll send it to my supplier and have him cross reference it. 

I gave away a big scarfing torch that would have worked perfect. I'm really hoping to get away with using an air propane mix though. But, if Oxy is necessary, at least it's cheap! I might collect torch handles and cool burners anyway. 

Oh...for raising and lowering something like this. I really like the use of gear racks and a spider handle. You end up with great control with minimal torque input.


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## snoman701 (Nov 28, 2017)

eastky2 said:


> me said:
> 
> 
> > To clarify, yes, this is to pour copper anodes from BRASS gold plated pins...
> ...



Really? It specifically says brass gold plated pins. I'm sorry if I confused you. I think it's clear that I meant gold plated brass pins. 


eastky2 said:


> While you are out looking for precious metal scrap and thinking $6000.00 for a years worth of riding around and picking up scrap is worth your time and gas good luck to you.
> 
> While your out riding around and burning gas. I will be online buying scrap that is already broke down and
> earning money.


Awesome. But in your post history, why is it that you rarely have anything productive to offer. In fact, a majority of your posts are usually negative towards either myself or Jon (anachronism).

I am happy with 6 grand profit. I earned it.


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## eastky2 (Nov 28, 2017)

snoman701 said:


> eastky2 said:
> 
> 
> > me said:
> ...


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## anachronism (Nov 28, 2017)

East and Sno. End it lads. It's not constructive. 

Yeah East has been pretty rude to me in the past but you know what? I know where I stand with him (I actually respect someone who doesn't blow smoke up your butt) and I don't bruise easily this is after all the internet. Sno you've also been a tad harsh in the past but here I am still trying to guide you to some common sense processing. I've also made my feelings clear about seeing some results from you after all the talk so I'm figuring we're pretty even.

Take it for what it is fellers and let's turn this back into being constructive before some moderator feels as though they have to put their boot in eh?

Onwards and upwards.

Jon


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## snoman701 (Nov 28, 2017)

anachronism said:


> East and Sno. End it lads. It's not constructive.
> 
> Yeah East has been pretty rude to me in the past but you know what? I know where I stand with him (I actually respect someone who doesn't blow smoke up your butt) and I don't bruise easily this is after all the internet. Sno you've also been a tad harsh in the past but here I am still trying to guide you to some common sense processing. I've also made my feelings clear about seeing some results from you after all the talk so I'm figuring we're pretty even.
> 
> ...



I'm going to send you a PM Jon.

This thread started out as constructive, and has remained so even though I am being trolled. I have tried to respond respectfully.


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## Shark (Nov 28, 2017)

I have been waiting to get started on a small rotary furnace. I have this thing that was meant to mix a 5 gallon bucket of cement. I am sure I can figure out something if I look at closer.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=61&t=25496#p270806


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## snoman701 (Nov 28, 2017)

We used to make glory holes for glass blowing by using a 30 gallon drum. Using 2" cerwool, you fold it in to U shapes, with the open end of the U out. Once you have the cerwool packed in there, you then use a rammable/pourable refractory to form the actual combustion chamber. (or crucible in your case)

A metal 5 gallon bucket with a reinforced handle and then another handle on the bottom. Pick it up and pour.

And by handle...I mean mostly lugs for you to grab on with appropriate molten metal lifting equipment.


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## 4metals (Nov 28, 2017)

These photo's of the schematics for a rotary furnace may help. I used the smallest one made for years to smelt jewelers sweeps with copper. They called it small but it was 4 feet in diameter and about 5 feet tall when upright and standing in it to reline it with new refractory. 







That size could melt 2 drums (55 gallon) full of prepared sweeps plus flux.


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## snoman701 (Nov 28, 2017)

4metals said:


> These photo's of the schematics for a rotary furnace may help. I used the smallest one made for years to smelt jewelers sweeps with copper.



How much copper did you add? Probably enough to make most efficient anode based on fire assay. 

Was the copper in powder form milled with the flux & sweeps, or just scrap copper?


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## 4metals (Nov 28, 2017)

Since jewelers sweeps essentially contain karat gold the rule of thumb was keeping the anodes at 1% precious metal so the anodes were close to 98% copper. The copper was added as shot made from the copper cell cathodes. 

We ran 2 drums of sweeps a day, blended with flux it was 4 drums and about 900 pounds of copper. The anodes in the copper cell performed well and eventually we halved the copper with no ill effects. 4 days of melting sweeps followed by slag Friday's. Slags were always remelted and always yielded 2-300 ounces of copper based collector metal for running in the cell. Considering we processed an average of 800 ounces of gold from sweeps a week the slag hang up was about 1/3 of 1% of the gold refined. 

The sweeps were mixed with flux components in a double cone blender and compressed into plugs with the equivalent of a gigantic pelletizer. Then about every 20 minutes, the flame was shut, the back door opened, and a plug was tossed in. After 5 minutes the flame went back on but the rotation never stopped. This minimized the burner blowing valuable dust out the front pour spout. The full charge of copper was added with the first few plugs and when it was molten, the routine of plug every 20 minutes was started. 

Metal accountability was always 99.7 or better after smelting, slag melting, and slimes processing but the anodes were assayed before going into the cell room so we knew what was going into the cells. Once the whole system was up and running we could produce about 800 ounces of fine gold a week. That was back in the day when jewelry was actually mass produced in the US!


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## snoman701 (Nov 29, 2017)

Awesome post! Thanks 4metals!



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