# Miller chlorination fume scrubbing



## elfixx (May 8, 2011)

I am curently gattering information on the miller chlorination process and I cannot find anything on scrubber CFM requirement. Anyone got a idea of how much CFM is required depending on the size of furnace/melt? I was also wondering if a poly made scrubber would be a problem considering the temperature of the fumes comming from the induction furnace. Would adding some lenght of heat resistant piping leading to the scrubber to allow fume to cool down be a option?
I know miller may not be suitable for the size of operation I have at the moment but I want to plan ahead to be ready for the time it will become economicaly viable.

Thank You


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## 4metals (May 8, 2011)

This has all been hashed out before, read it here; http://goldrefiningforum.com/phpBB3/viewtopic.php?t=7349

Why are you trying old technology, there are better ways.


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## elfixx (May 8, 2011)

Unfortunatly there is no reference to CFM requirement, the only thing discussed is the use of a industriac vacuum cleaner. What do you mean old technology? are you thinking of a atomiser as a better more efficient way to go? I just dont know, atomising the gold scrap and digestion in AR still involve large volume of AR to be handled and require large vessel, scrubber, filtration and pumping equipment.... I'm thinking miller because it's quick and require no liquid handling and no special equiment other than a scrubber a furnace and some hose/pipe and in only a few hour the gold is ready for the electrolytic cell.
By the way, got a idea where I could find one of these industrial vacuum cleaner that could be used as a scrubber?


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## HAuCl4 (May 8, 2011)

Inquart with zinc, nuke it with nitric, recover the nitric, the silver, the PGMs, the zinc, then pour your fluxed 9995 gold in 2-3 hours and be ready for the next 400 OZ bar melt. At a fraction of the cost. No Miller, no atomizer, only the "big johnson" scrubber, a few buckets, and a furnace. :shock:


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## PreciousMexpert (May 8, 2011)

HI Folks
Just when I thought I had seen it all now there is big johnson.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=8619&p=80788&hilit=big+johnson#p80788
Can someone tell me about the difference between this scrubber and the other scrubber 4metals has in his posts
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=4776
Thanks


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## PreciousMexpert (May 8, 2011)

Hi HAuCl4 


> Inquart with zinc, nuke it with nitric, recover the nitric, the silver, the PGMs, the zinc, then pour your fluxed 9995 gold in 2-3 hours and be ready for the next 400 OZ bar melt. At a fraction of the cost. No Miller, no atomizer, only the "big johnson" scrubber, a few buckets, and a furnace.


This something new from the way we have seen refining in here
Can someone talk a bit about this
Thanks


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## Refiner232121 (May 9, 2011)

> Hi HAuCl4
> 
> Inquart with zinc, nuke it with nitric, recover the nitric, the silver, the PGMs, the zinc, then pour your fluxed 9995 gold in 2-3 hours and be ready for the next 400 OZ bar melt. At a fraction of the cost. No Miller, no atomizer, only the "big johnson" scrubber, a few buckets, and a furnace.


Did anyone try this 
I wonder what Harold thinks of this


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## Lou (May 9, 2011)

There's no recovering the zinc. 


Unless you're doing tons of gold, forget about Miller. Especially when it comes to the bag house, fume containment, etc. That and don't forget that the second you order that Cl2 cylinder you're going to need to get a OSHA and the EPA involved. 

Plus, the gold you get isn't quite commercially pure (it doesn't remove PGMs!).


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## HAuCl4 (May 9, 2011)

Zinc is about $2,100 per TON. Not worth recovering everytime. After you get all the metals out by cementation (with minimal supervision), you are left with zinc nitrate. Here you can calcine the nitrate and circulate the NOx thru the "big johnson" with a residue of ZnO, or more practically, convert the zinc nitrate to zinc sulphate, and recycle the nitric, saving the sulphate crystals. You can keep the clean zinc sulphate in drums for a long time (it is also an animal feed). You can sell it like that, or if in big quantities, you can recover the zinc, although it is a lot of work.

As Lou said, it will not remove platinum from the gold, but the palladium will be removed.

but the original OP wanted to pass the bars through electrolysis (again bad idea)...but...the platinum would be recovered that way. :lol:

What Lou said about Miller is probably true also. Not worth the troubles except for the biggest of the big.

You should read that thread 4metals pointed out. The easiest, fastest way is chemical, one variation or the other. Atomizing is the most elegant route, but inquartation is probably a tad faster, simpler processing, and does not need an atomizer. 

For anyone doing less than 400 OZ per week (99.99% of readers?), inquartation (and if more purity is needed AR chemical processing) is the way to go. IMHO.


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## elfixx (May 9, 2011)

Electrolysis a bad idea? I curently process all my gold with electrolysis and even on a small scale of only 10-15 ounce it realy worth it. Superior quality each and every time. Everyone told me that gold electrolysis was useless, very expensive and complicated for my size of operation but I did it and it worth it, so I dont see how a small miller process couldn't be acheivable. From what I've readed people have done it on small melt of only 3-4kg. One thing that you must understand is that I'm not trying to set up such a process for my current productivity, I'm just planning ahead, gattering information and doing test.


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## HAuCl4 (May 9, 2011)

I did have your same thinking many years ago. It's all in the thread 4metals pointed out. His story with Miller as a relatively large refiner, and mine as a relatively small one. Both of us have the current opinion that there are better ways. It is not that it is hard or undoable. At the end you'll have to convince yourself. It is in fact extremely simple to refine by Miller, and electrolysis will produce very fine product, but it'll take a long time. Why work 2-3 days when you can do it in a few hours, and MOST IMPORTANT OF ALL have the gold sleep elsewhere and not under your care/vault/insurance, etc.

I even put up pictures of a crucible (new) and a chlorination tube (used) with the characteristic purple stain. (First ever posted on the net anywhere, as far as I know).

Read my lips: NOT WORTH IT!. Interesting?. YES. VERY. :lol:


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## elfixx (May 9, 2011)

All right, worth it or not, would it be possible to get any kind of a answer on how much CFM is required in relation to the size of the melt?
Please

Thank You


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## HAuCl4 (May 9, 2011)

Sure. If you use induction or electric furnace, very little. A household vaccuum cleaner will suffice. If you plan on using a gas fired furnace, my suggestion is change your plan. :lol:


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## elfixx (May 9, 2011)

No I will use my induction furnace, I readed you used a industrial vaccum cleaner for you setup, what kind of vaccum was it, it must have been all plastic? Could you suggest a particular model and general guideline on how to modify it to neutralise the fume? 300$ to get rid of the fume is way too interesting to be ignored  considering the outrageous price of comercial fume scubber.


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## 4metals (May 10, 2011)

The CFM of the exhaust is a function of the retention time in the scrubber for effective scrubbing. Conventional wisdom has that retention time pegged at 1 second or better. 

I would not like to see any less than 100 CFM for exhaust over a melt and with chlorine I would go higher. For small melts that would be 250 CFM for me to be satisfied. So you will need a scrubber that is big enough to hold the fume in the reaction zone of the scrubber for a full second. That's a scrubber with a packing volume of 4.2 cubic feet. Bigger is better but chlorine is a much easier fume to scrub than NOx. 

I don't know about Canada but in the US if you start using chlorine gas, the EPA will be up your butt so fast you may wish you hadn't even tried it. They never seem to let you go either. You can say I tried it and it didn't work out so I'll never use chlorine gas again, and they'll say, sure I believe you, see you next week. 

I remember when you started talking about setting up the electrolytic gold cell and everybody told you it isn't worth the effort. I remember quoting Hoke when she said something to the effect that it takes as much operational control to run a small cell as a big one, and for small producers it doesn't pay. You did it and you're apparently satisfied with the result and don't mind the control. You will find the same is true with the Miller process, you can do it, but why? There are better, more modern methods out there. The Miller process has been around since people went to work on a horse!


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## Harold_V (May 10, 2011)

Refiner232121 said:


> > Hi HAuCl4
> >
> > Inquart with zinc, nuke it with nitric, recover the nitric, the silver, the PGMs, the zinc, then pour your fluxed 9995 gold in 2-3 hours and be ready for the next 400 OZ bar melt. At a fraction of the cost. No Miller, no atomizer, only the "big johnson" scrubber, a few buckets, and a furnace.
> 
> ...


I don't think much of it. I see no logical reason to use zinc when silver serves the purpose perfectly well, and achieves double duty (and more, when you consider the platinum group). I used silver exclusively as long as I refined. Call me lucky, but I seemed to manage a relatively balanced situation whereby silver came in for refining at a rate that was in keeping with my needs for inquartation. I found it convenient to use, and relied on residual silver chloride for future recovery of values from my waste materials, plus I enjoyed the fact that silver became the carrier for platinum and palladium. Worked perfectly well for me. I didn't need no stinkin' zinc. 

For me, the plan I chose was a perfect glove fit. It was also a plan of reality. My purpose in refining was to achieve pure gold and silver, and to accumulate all the platinum and palladium I could. I had no interest in reinventing the wheel----I did almost no research once I discovered functional methods of processing. Spend your time processing, not spinning your wheels. That logic permitted me to retire (comfortably) at age 54. I have no desire to work, nor need. As I said, my plan worked to perfection. YMMV. 

Harold


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## Oz (May 10, 2011)

I am of a very similar mind as Harold on this but have been too busy to reply. Zinc has a lot of problems that I would not want in my refining environment. Traditional silver inquartation has all the characteristics I do want however. The largest being the recovery of PGMs. 

It should also go without saying, silver is easily recyclable, zinc is not. 

HAuCl4, I understand your enthusiasm for alternate processes, in fact I enjoy the intellectual exercise of some of your divergent posts. However (as I have said in the past to you) too many here are new to refining and you need to be very clear as to speculation vs. factual “you are doing this” and the hazards of such procedures if you are going to write about them. Many of your speculations could be injurious to those that lack a chemistry degree, or even those that have refined without one for a protracted period of time, in order to have an innate idea as to potential hazards.

*So I once again ask you to preface your ideas with the fact that you are not recommending them as a procedure you are using safely, but as speculation for comment.*

If you are currently using these as regular processes in refining, you should be clear that they deviate from generally accepted practice and there are significant hazards beyond what you have expressed and should only be tried by a degreed chemist.


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## HAuCl4 (May 13, 2011)

Silver required by a miner to produce a pure 400 OZ gold bar: approx. $40,000

Zinc required by a miner to produce a pure 400 OZ gold bar: approx. $64.00

End of discussion.


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## Oz (May 13, 2011)

Anyone refining karat scrap receives about 7% silver as a byproduct of their gold refining for free. It is infinitely recyclable and you continue to accumulate it as your operation grows. 

Why pay anything for zinc, and then have to pay again to dispose of it as waste? Not to mention the other disadvantages of zinc outlined above.


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## Barren Realms 007 (May 13, 2011)

HAuCl4 said:


> Silver required by a miner to produce a pure 400 OZ gold bar: approx. $40,000
> 
> Zinc required by a miner to produce a pure 400 OZ gold bar: approx. $64.00
> 
> End of discussion.



It needs to be stated for the people that are not familar with this that when you go to wash your material with HCL to remove the remaining zinc, that hydrogen is produced that in the right mixture and quantities can creat very dangerous and damaging explosions.

I saw the after effects of one of these explosions in a plant I worked in. A 24' dia. fiberglass tank with an H-frame built out of 8" I beams and supporting a 25 HP motor and a 4' dia. impeller were all torn out of the concrete base and flipped 90 deg. And bent a 14" I beam above the tank. All because the production personel mixed zinc and HCL and didn't run the exhaust blower. Hydrogen in a confined space is nothing to play with.


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## Harold_V (May 14, 2011)

Oz said:


> Anyone refining karat scrap receives about 7% silver as a byproduct of their gold refining for free. It is infinitely recyclable and you continue to accumulate it as your operation grows.
> 
> Why pay anything for zinc, and then have to pay again to dispose of it as waste? Not to mention the other disadvantages of zinc outlined above.


Exactly.
And, as he said, "End of discussion." The idea stinks, at best. 

Do not encourage people to use zinc. We don't need to read about readers being hospitalized. 

Harold


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## HAuCl4 (May 14, 2011)

Good thing the idea wasn't mine, but C.M. Hoke's who probably took it from someone else. Take up your issues with zinc with her ghost!. :lol: 

As a safety warning: be careful with zinc fumes, do not inhale them. Do not drink or pour nitric acid on your skin either. It's dangerous!.  

$40,000 vs $64 in capital to start a relatively large refinery... no contest!.


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## elfixx (May 14, 2011)

May I post a reminder? This topic about miller chlorination and it's fume treatment.... If I was thinking about continuing wet chemical refining and switching to zinc inquartation instead of silver the topic would have been properly named / Zinc Inquartation. For now what I'm interested in is setting up a efficient chlorine fume scrubber at low cost.

Just to be clear: I'm not thinking, not even a second about switching to zinc inquartation, not at the moment nor in the futur.
And considering the danger involved compared to the simplicity of using silver to inquart I would not suggest anyone to use this technique.


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## HAuCl4 (May 14, 2011)

elfixx said:


> And considering the danger involved compared to the simplicity of using silver to inquart I would not suggest anyone to use this technique.



Do you plan to skim the melt in your Miller implementation or not skim the melt and break the crucible after it cools?. If you use a disposable crucible then the fumes are much less. Still a lot more than using silver inquartation...or shall I mention...zinc?. :lol: 

The only metal I love more than zinc to process precious metals is lead. Those two metals, zinc and lead, have magical properties, and are extremely useful, in the proper hands. :shock:


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## elfixx (May 14, 2011)

For my purpose I plan on leaving the melt in the crucicle, let it cool then break the crucible appart.


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## Oz (May 14, 2011)

You are more than welcome to have an opinion that differs from others here. What disturbs me about your reply is its childish taunting tone targeting Harold of all people. 



HAuCl4 said:


> Good thing the idea wasn't mine, but C.M. Hoke's who probably took it from someone else. Take up your issues with zinc with her ghost!. :lol:


Why would you make a statement like that and post a “laughing" emicon after it? The idea may not be original to you, but *you* are the one that brought it up and recommended it. For the record I do not own a copy of Hoke but did read it online several years ago. If I remember correctly she also incinerated with gasoline, poured waste acids down the drain on occasion that would land you in jail today, and even talked about removing mercury from small batches of amalgam using a potato half over it in a very hot iron skillet. Do not even begin to promote those procedures here!

Hoke was written nearly a hundred years ago and needs to be read in that light. It is however one of the best books to this day that comprehensibly teaches refining to the layman, especially because of her promotion of acquaintance experiments. Yes, you knew that Harold is very fond of Hoke. He has good reason to be as that book shared with him what others would not. It allowed him to start a very successful refining business and retire young. 

As I said, you are welcome to your opinion, but if you choose to taunt others you will likely have a vacation. Persist, and it is you that will become the ghost here. 

Elfixx, please accept my apologies for this distraction from your questions on chlorine gas scrubbing.


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## HAuCl4 (May 15, 2011)

Wow, a bit "touchy" to say the least. aren't we Oz?. :lol:  :lol: 

elfixx: 4metals is the resident expert in Miller process with disposable crucibles. I suggest you PM him, if your interest is for real. If you posted a photo of your induction rig and furnace, that would probably help things, as the scrubber, etc has to be custom fitted to the induction furnace for best results. It is all pretty simple.

Good bye all!. If anyone has any tips on gold inquartation with sodium or magnesium, please PM me, I'm having trouble getting it right!. :lol: 8)  :idea: :lol: :shock:


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## elfixx (May 15, 2011)

I will post pic of it as soon as I receive it, I've ordered a 9KW medium to high frequency( 1-100KHz) power supply 5Kg gold/silver capacity, I'll build a crucible chamber out of castable refractory to protect the coil and add some safety to the setup. Do you think I should cast the coil directly into the refratory material or just slide it into the cement box and use some furnace lining to cover the copper coil? I am also planning to build my own scrubber, if I'm using a 450cfm fan sucking trought 6feet of scrubbing media do you think the air flow will be considerably reduced to the point where I should think of using a bigger fan?


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## Harold_V (May 16, 2011)

elfixx said:


> I will post pic of it as soon as I receive it, I've ordered a 9KW medium to high frequency( 1-100KHz) power supply 5Kg gold/silver capacity, I'll build a crucible chamber out of castable refractory to protect the coil and add some safety to the setup. Do you think I should cast the coil directly into the refratory material or just slide it into the cement box and use some furnace lining to cover the copper coil?


The builder of the induction furnace should be able to provide acceptable guidelines. 
Coils are often set in refractory, but you must be able to clean the old refractory for coil maintenance. I'd highly recommend you do some research so you follow acceptable procedures. 

I'd enjoy seeing a picture or two of your furnace when it arrives. I have a keen interest in induction heating. 

Harold


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## elfixx (May 16, 2011)

I will


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## elfixx (May 28, 2011)

I have another question related to the scrubber construction, if the media chamber is about 2,5 feet large by 4 feet tall what kind of pump would I need? If I'm placing 5 spraying nozzle how many gallon per minute and how much psi would be required? 
And by the way does anyone know some place where I could buy such a pump and spraying nozzle?

Thank You


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## Fournines (May 28, 2011)

I'm not an expert on induction melters, but all of ours have water cooling systems. This keeps the coil itself from melting down.

Just something to think about.


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## HAuCl4 (May 28, 2011)

Fournines said:


> I'm not an expert on induction melters, but all of ours have water cooling systems. This keeps the coil itself from melting down.
> 
> Just something to think about.




Where's MY platinum video????. :lol: 8)


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## elfixx (May 28, 2011)

I was not asking for the water cooler pump but the caustic solution pump for the fume scrubber.


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## Fournines (May 28, 2011)

HAuCl4 said:


> Fournines said:
> 
> 
> > I'm not an expert on induction melters, but all of ours have water cooling systems. This keeps the coil itself from melting down.
> ...



Working on it! I'm bringing in a better camera. Shot the last one with my iPhone 8)


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## Fournines (May 28, 2011)

elfixx said:


> I was not asking for the water cooler pump but the caustic solution pump for the fume scrubber.



I know. I was asking about your induction melter - (that you are apparently building yourself?) Depending on how powerful it is, the coil might need to have an additional water cooling system so it doesn't melt itself down.


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## Harold_V (May 28, 2011)

Fournines said:


> elfixx said:
> 
> 
> > I was not asking for the water cooler pump but the caustic solution pump for the fume scrubber.
> ...


I know of no circumstances where water cooling of the coil isn't a requirement. Induction furnaces have the ability to achieve temperatures well above that which can melt even platinum, as you know. Copper coils wouldn't stand a chance were it not for cooling. 

In my induction power supply, capacitors are also water cooled. 

Harold


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## elfixx (May 28, 2011)

The cooling unit is already part of the furnace I am buying, I just have to connect water in and out with a pump to circulate the water. The only thing I will have to build is the refractory box itself.


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## Lou (Jun 6, 2011)

HAuCl4 said:


> Wow, a bit "touchy" to say the least. aren't we Oz?. :lol:  :lol:
> 
> elfixx: 4metals is the resident expert in Miller process with disposable crucibles. I suggest you PM him, if your interest is for real. If you posted a photo of your induction rig and furnace, that would probably help things, as the scrubber, etc has to be custom fitted to the induction furnace for best results. It is all pretty simple.
> 
> Good bye all!. If anyone has any tips on gold inquartation with sodium or magnesium, please PM me, I'm having trouble getting it right!. :lol: 8)  :idea: :lol: :shock:



I've had gold-sodium alloy before. It wasn't fun to melt.



Elfix, what I would do is get some kaowool blanket and wrap that around the coil. That's what I did with mine. It won't work for Pt since that'll liquify the kaowool.
Since there's no flame and no air movement, there's minimal concern about silica fume from the fiber blanket. For a platinum induction melter, the absolute best refractory to use is Zircar's Alumina Bubble insulating refractory.


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## HAuCl4 (Jun 7, 2011)

Lou said:


> HAuCl4 said:
> 
> 
> > Wow, a bit "touchy" to say the least. aren't we Oz?. :lol:  :lol:
> ...



I'm going to go out on a limb and think that the parting was very fast!. :lol:


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## Lou (Jun 9, 2011)

Turned out it was AuNa in a gamma-alumina matrix. Super bizarre stuff!


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## HAuCl4 (Jun 14, 2011)

elfixx said:


> I was not asking for the water cooler pump but the caustic solution pump for the fume scrubber.



The fumes aren't acid, so no need for caustic. A soda ash solution in water is more than enough, two drums in series already overkill, as everything stays in the first drum you bubble through. Vaccuum at the end of second drum exhausts clean air. Simpler is better.

For a 5 Kg of charge, 150 OZ I prefer to use a used $25 cast iron pot and some drain cleaner sulfuric instead. But that's just me. Only for 200 Kg+ of gold melt at a time I would consider Miller again.That means...that I will never consider it again... :shock: 

Republic does 1,000 Kg at a time and has replaced Miller by atomizer. It's all in this forum in one thread or another.

Where is the 5 Kg induction furnace?. :shock: :lol:


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## elfixx (Jul 17, 2011)

Here a few picture of the furnace and my working environement as well.


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