Mercury retort

[PreciousMexpert]

having one cast in ductile iron would be the best of all worlds.

Is this something I would be able to cast myself with a crucible burning furnace

 

[Harold_V]

having one cast in ductile iron would be the best of all worlds.

Is this something I would be able to cast myself with a crucible burning furnace

Very unlikely. There are some serious issues with melting iron in a crucible furnace. The chemistry of the iron is altered due to the burnout of carbon.

Unless you have a very well built furnace with the proper burner, you likely can't achieve the temperature required to melt cast iron. Assuming you can, you must inoculate the molten iron with a magnesium compound, which causes the graphite to form nodules instead of forming flakes. The inoculation has a relatively short window of opportunity to function, so re-melting ductile iron will not result in new ductile iron, but gray iron, or even white iron, depending on the time spent in the furnace.

In order to achieve success, the iron involved must have a low sulphur content, otherwise the inoculation fails.

You'd be far better served to find a foundry that specializes in ductile iron and have one poured. If you had the necessary equipment, I would encourage you to make a set of patterns and offer them for sale.

Harold

 

[PreciousMexpert]

Hi Harold
I have spent a while studying this concept

http://practicalaction.org/practicalanswers/product_info.php?products_id=281&osCsid=oiba76b9j52211nnuhnickt8q0

I really like it

Question 1
i guess I will be able to make the
# ½ - 1½ inch galvanised iron pipe reducer (2c)
a bit larger

Question 2

Transfer the recovered mercury to a proper container. To prevent evaporation of mercury while being stored, put a layer of water over the mercury.

What do you do with this

Question 3

Wrap the amalgam into small balls with a piece of paper (the foil from a cigarette packet is ideal). This will help prevent the gold from sticking to the distilling chamber under heat.

I thought you it would need water but it looks like they know what they are saying

 

[Harold_V]

I have spent a while studying this concept

http://practicalaction.org/practicalanswers/product_info.php?products_id=281&osCsid=oiba76b9j52211nnuhnickt8q0

I really like it

Question 1
i guess I will be able to make the
# ½ - 1½ inch galvanised iron pipe reducer (2c)
a bit larger

I wouldn't use that system unless you put a cooling jacket on the condensing pipe. As the mercury evaporates, it rapidly heats the pipe. Without cooling, you risk mercury vapors exiting the discharge. I wouldn't take the chance, even if they condense in the water. Some may not.

I would also discourage you from using ½" pipe. It would be difficult to bend if nothing else. You should be able to buy ¼" black iron pipe at a plumbing supply house, although unless they have some nipples, you may have to buy a full length.

Also, look for fittings that do not have zinc. They should be just as available, and will save you the trouble of removing the zinc. Again, a plumbing supply house would be the source.

Question 2

Transfer the recovered mercury to a proper container. To prevent evaporation of mercury while being stored, put a layer of water over the mercury.

What do you do with this

I was never that worried about mercury, although I'm not suggesting that you share that attitude. If you are concerned, store the mercury in a heavy plastic container with water on top. I kept mine in plastic containers with no water. I did use lids.

Question 3

Wrap the amalgam into small balls with a piece of paper (the foil from a cigarette packet is ideal). This will help prevent the gold from sticking to the distilling chamber under heat.

I thought you it would need water but it looks like they know what they are saying

They're talking about the gold sticking to the retort, which has nothing to do with water. I used to use a thin piece of asbestos paper to isolate the contents from the bottom of the retort. Mine was made of stainless, which I found to dissolve slightly in mercury. You probably won't have that problem with iron fittings. They will degrade from heat if they are heated very hot, however.

As far as the gold sticking, unless you approach the molten state, that shouldn't be a problem, although with threads forming the base of the retort, I expect you will have trouble regularly. I don't like the design, but that may be the only thing available to you.

Harold

 

[PreciousMexpert]

Hi Harold
How are you
Thanks very much for being helpful

Question 1
I don't know much about

 ¼" black iron pipe

Would I be able to find a container in this material

Question 2
You used

 ½" diameter stainless

I suppose you don't need a

cooling jacket on the condensing pipe.

when you use stainless

Thanks again for your help

 

[Harold_V]

Not clear on your questions, but using stainless in no way eliminates the need for a cooling jacket. You can see it clearly in this photo.


As far as size of the retort body, you'd buy a bell reducer, so size is your option. You may have to adapt by using a reducing bushing, but you should be able to go from ¼" pipe to as large as you desire. Remember, 2" pipe is more than 2" inside diameter. A 2" bell reducer would give a chamber size about 2-3/8" diameter. You'd buy the appropriate plug for the size bell reducer. Does that answer your question? If not, please ask in a more direct method, using more words.

Harold

 

[goldnugget77]

Hi Harold
How are you
Those pictures are a big help

I understand that the part where the metal is placed should be ductile iron
In your picture you have a pipe that is in between the condenser and the compartment where the gold goes
What kind of metal is this and it doesn't look like it has any protection

That thick tube the condenser how was that made

Stainless also needs a cooling jacket

Also where is the cooling jacket


I found this site that sells galvanized products but you said galvanized is not that good


http://www.morrillinc.com/m_galvanized_fittings.aspx


Sorry for sounding confused when it comes to mercury there isn't many choices of metals and materials to use.

Also it seems like everything you do with mercury is hazardous

Would it be OK to refine when there is mercury in the batch
For example if there is 4 gram of mercury in 100 ounces of gold

Thanks for your patience

 

[AKDan]

I haven't read back through this thread to get what kicked it off, or how it progressed. But, based on the last few posts, here is some information on mercury, its hazard, useage, recovery, etc...

http://www.prospectorsparadise.com/html/mercury.html

a plan for building a simple retort, though this one does not show or have a cooling jacket.

http://practicalaction.org/practicalanswers/product_info.php?products_id=281

Another site with a reasonable plan view for a retort, this one with a water jacket.

http://nevada-outback-gems.com/Reference_pages/Amalgamation.htm

Action mining out of Oregon used to sell a mercury retort, but I can't find it in their catalog now. However, there are other items that may be of interest. In fact, they sell C.M. Hoke book there too. Price is high, but it is available.

http://www.actionmining.com/Catalog.PDF

This place still sells a retort. It looks to be a well built, practical unit that should operate as expected. From their catalog, the device sells for 129.00 or so. Look under the heading for Assaying and Refining Supplies.

http://www.abprospecting.com/

Again, A&B sells other items that will likely be of interest to other members of this forum. Everything just costs money.

 

[goldnugget77]

Air Press (Air Tort)
We developed this years ago for safer handling of mercury amalgam! Made of PVC
which you attach to an air compressor, using only 12 lbs. of pressure. It pushes the
mercury out and leaves the amalgam on the filter. Safer to use than retorting as there
are no mercury vapors. Comes with a 4 micron polypropylene filter and stainless
steel screen. Holds 15 lbs. of mercury.
Cat #AIRPRESS1 Price 35.50
Replacement parts:
Air press end cap parts AIRPRESSEND $ 7.50
4 micron poly filter AIRPRESSFIL 2.50

This one seems like a good way http://www.actionmining.com/Catalog.PDF
----------------------

http://www.abprospecting.com/

This also looks good I dont know what the price is
---------------------
http://nevada-outback-gems.com/Reference_pages/Amalgamation.htm
Hi Harold
This looks like your system
The thing is how do you make that water jacket and what happens to the tube that does not have a jacket
Why is left without a jacket
----------------------

 

[Harold_V]

In your picture you have a pipe that is in between the condenser and the compartment where the gold goes
What kind of metal is this and it doesn't look like it has any protection

The entire retort was built from stainless, so the pipe you see between the condenser and the retort body is ½" stainless tubing. It is one continuous piece, from the retort body to the discharge end. It has no protection because it doesn't need any. Anything between the condenser and the retort body will contain mercury vapors, but they are being transported to the condenser, where the temperature in the tubing drops drastically, so they condense. Once they have cooled and condensed, there is no further need for the water jacket (the large tubing that is over the ½" tubing), because it is expected that there are no vapors remaining. In practice, that proved to be correct. The fabric on the end prevents the retort from sucking water in, although in my experience it didn't work. I found traces of water in my retort when it was opened, but not routinely. By the time water reached the chamber, temperatures were low enough that there were no problems as a result. It's important that no water reach the retort when it's heated, which could result in a steam explosion.

That thick tube the condenser how was that made

It's important that you keep in mind that I am a (retired) machinist, and that I have machines at my disposal. The condenser was made from large stainless tubing, to which I silver soldered fittings for the water to enter and exit. To seal the tube, end plates were machined from stainless sheet, which were in turn silver soldered to the assembly. By circulating water through the condenser, temperature at the discharge was equal to ambient room temperature.

Also where is the cooling jacket

That, of course, is the large diameter tubing I just discussed. You don't want any cooling between the condenser and the retort body, otherwise you get condensing prematurely, where some of it will drip back into the retort body. It's very desirable to keep the mercury in a vapor state until it reaches the condenser.

I found this site that sells galvanized products but you said galvanized is not that good

Avoid galvanized material, which will form an amalgam with mercury. If you find you must buy galvanized components because you can't locate them in what is commonly termed black iron, you can remove the zinc using lye. HCl will dissolve it in a heart beat, but it also promotes rusting. Lye won't rust the parts.

Also it seems like everything you do with mercury is hazardous

It certainly can be. While I didn't lose any sleep over keeping mercury in containers without a water cover, I still respected the fact that it has the potential to be a killer.

Would it be OK to refine when there is mercury in the batch
For example if there is 4 gram of mercury in 100 ounces of gold

In my opinion, no, it wouldn't. It's important that you don't form any compounds of mercury, some of which can be extremely unstable. In all cases, they are harmful to you and the environment. Personally, I wouldn't process anything that had mercury included. I practiced what I preached in that regard. After my silver amalgam was retorted, it then received a heating in my fume hood to the point where it was molten. It was then stirred well, to oxidize the tin content. Any residual mercury was driven off.

Here's something to think about. Mercury dissolved in nitric acid can form an explosive compound with the introduction of alcohol. Drizzle a little of that beer you may be drinking into your solution and you have the potential for an explosion.

I highly recommend you eliminate all mercury before attempting any processes. Simply expelling mercury by force isn't enough. Once an amalgam is formed, you should distill the mercury in order to eliminate it totally. Said another way, you MUST retort to get rid of mercury once it has formed an amalgam. It can not be removed by filtration or other means, although free mercury can be.

Harold

 

[Platdigger]

edit

 

[qst42know]

As far as zinc free steel tubing goes has anyone considered seamless steel hydraulic lines?

Some grades (wall thicknesses) should be very easy to bend.

 

[golddie]

goldnugget77 on September 2nd, 2009, 12:43 pm

Air Press (Air Tort)
We developed this years ago for safer handling of mercury amalgam! Made of PVC
which you attach to an air compressor, using only 12 lbs. of pressure. It pushes the
mercury out and leaves the amalgam on the filter. Safer to use than retorting as there
are no mercury vapors. Comes with a 4 micron polypropylene filter and stainless
steel screen. Holds 15 lbs. of mercury.
Cat #AIRPRESS1 Price 35.50
Replacement parts:
Air press end cap parts AIRPRESSEND $ 7.50
4 micron poly filter AIRPRESSFIL 2.50


This one seems like a good way http://www.actionmining.com/Catalog.PDF
----------------------

http://www.abprospecting.com/


This also looks good I dont know what the price is
---------------------
http://nevada-outback-gems.com/Referenc ... mation.htm

What do you guys think of these

 

[AKDan]

They work. However, you will still need to either retort off the mercury from the amalgam, or use nitric to clean off the mercury in order to get the gold cleaned up. Using one of the presses, or a chamois has always just been a way to extend the use of the mercury. By pressing through a filter you get the bulk of the mercury back into production while the small amount that is still almalgamated with the gold is held in reserve. Also, there is no reason to run all of the mercury throught the retort every cycle. The mercury comes off quicker so you are using less energy, etc... when you press it off first, then retort that which will not pass through the press.

As Harold has pointed out a few times here already, there is no substitute for a well built, well maintained, properly operated retort.

 

[goldnugget77]

Hi Folks
Thanks for your the knowledge on this terrible metal mercury.
Hi Harold
You're knowledge on the subject of retorts is very extensive.

Thanks for clearing up the confusion now I understand the concept very well
I have the confidence to make a retort
There are some important facts to keep in mind with retorts

NEVER put the exit end under water in a catch vessel. If you do, a very slight drop in the temperature of the boiling Mercury will create a vacuum sufficient to suck water back through the system right onto the boiling Mercury. This will almost certainly create an explosion, blowing iron shrapnel, poisonous mercury vapors and your gold all over the place. Please believe me when I tell you, that it is a bad idea and extremely dangerous! It may well ruin the rest of your life and probably put you in the hospital (if you are lucky). One thing to note is that as mercury come out of the retort and into the mercury receptacle, the water level will rise as mercury is added to the receptacle. This needs to be noted so that you don't get in trouble with the problem of water being sucked into the retort vessel as described above.

I got this from here
http://nevada-outback-gems.com/Reference_pages/Amalgamation.htm

Also I have seen this from a link Akdan gave us
http://www.abprospecting.com/
This is very much like the concept you are talking about
What do you think of this
Does it look like it could do the job
Thanks again for helping
I hope that you are also getting something good out of this forum.
Its always us asking the questions and you replying all the time.
Maybe one day we will be able to return the favor

 

[Harold_V]

Does it look like it could do the job

That's pretty much what I was thinking. Note the discharge has a cooling jacket, which I consider to be very important. I would also recommend that you use a small fountain pump to circulate water. The intake should always be the low side, with the discharge being the high side. That way the jacket will always be full of water.

I hope that you are also getting something good out of this forum.

Just the pleasure of trying to help. I am no longer involved in refining, but I recall all too well how hard it was to learn these things.

Harold

 

[goldnugget77]

Hi Harold
How are you
Thanks very much for giving us guidance

 

[JOE S (INDY)]

Folks, I have finally found a small area that I can help with here. Finally!

Mercury vaporizes, for all practical purposes, at 350 deg C. http://www.integrachemical.com/msds/M560_005.pdf

Mercury, especially HOT Mercury vapors, react with Aluminum, Silver, Copper, Stainless Steel, Zinc and a variety of other metals (all to some degree).

Iron is the "Silver Bullet" (oh, please forgive me for that one!) in distilling mercury from amalgam. Use Iron and you will have no trouble.

I use black iron plumbing parts to make the vessel, reducers and cooling discharge pipe for the distilling process. Please note that I did NOT include any reference to any kind of a water jacket here. It's NOT needed to provide any kind of additional cooling to drop the vapor temperature to less than 350 deg C. where the Mercury vapor reverts to it's liquid state.

So, an enclosed chamber, which will not leak vapors to the ambient air (for you and I to breathe) and a sufficiently long discharge tube to permit cooling / condensation of the Mercury vapor are the bare bones need here. Yes, you can add a water cooled condensor, lights, bells, whistles, smoke and mirrors -but those peripherals are not needed.

Of course, barring the use of a fume hood (wish that I had one) the only real worry is that of breathing Mercury fumes - and that problem is rather well resolved using strict attention to good ventilation procedures and common sense.

Some still feel that they must use water in some way to """Distill""" anything. If you feel compelled to put water in the equation (wet rags, pools of water for underwater discharge of fumes, water "traps", etc) please use the old and true technique of putting a small 'weep hole' in the low end of the discharge tube to allow no suction of water back into the hyper heated distillation chamber.

Oh, always, ALWAYS store any Mercury or Amalgam under water, it stops evaporation of the Mercury over long periods.

http://webpages.charter.net/kwilliams00/bcftp/bcftp.htm

Joe

 

[AKDan]

Bouncing around a little joe

I agree, the water jacket is not "strictly" necessary, but you have to admit it does help. You don't have to have quite as long of a tube on bigger batches, or for longer runs on lots of material. The process seems, for me, to go quicker with a unit that has a water jacket.

Good call too on the black iron only for the retort. Folks not working with mercury that much don't realize just how many common substances that it does react with, some violently. Aluminum being one of the big offenders.

One thing you didn't mention was thread sealing at all the joints. Once the black iron is heated a few times, rust and oxidation start to be an issue at all the joints. A good joint compound applied to the parts that do come apart with every run becomes necessary to eliminate/minimize vapor leaks.

How about some pictures of your cleanups from this year?

 

[Harold_V]

Of course, barring the use of a fume hood (wish that I had one) the only real worry is that of breathing Mercury fumes - and that problem is rather well resolved using strict attention to good ventilation procedures and common sense.

Yes. Common sense. That includes providing a cooling jacket. To imply that it isn't necessary isn't the smartest thing you've had to say. It's a lot like telling readers that seat belts, in cars, aren't really necessary, either.

What a cooling jacket does is INSURE that there will be a sufficient temperature drop between the retort and the discharge to insure that there are no fumes escaping.

I'm not suggesting that a fume hood isn't a good idea, but a cooling jacket on a retort is much cheaper, and stops the problem instead of changing the nature of the problem. Keeping fumes from escaping is far better than re-directing escaped fumes.

I strongly advise a cooling jacket for retorting mercury. That's especially true if it is retorted in volume.

Harold