# Reaction flask



## autumnwillow (May 3, 2018)

What reaction flasks do you guys use?

I am thinking of upgrading the vessel for my reaction flask. Currently I use a 4L erlenmeyer with side tube.

Now if I were to switch to a 10L reaction vessel, all I see is in the market are round bottom flasks or boiling flasks.
If its that big how does one remove solids and/or the liquid from such a big flask? 
Example pregnant AR or gold left out from nitric digestion?


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## cuchugold (May 4, 2018)

Maybe you'll enjoy this old thread:
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=7349


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## Lino1406 (May 4, 2018)

Old Buchner was frustrated to hear that HIS flask is called "Erlenmeyer with a side tube"


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## kurtak (May 4, 2018)

Lino1406 said:


> Old Buchner was frustrated to hear that HIS flask is called "Erlenmeyer with a side tube"



:lol: :lol: :lol: - I've always called it a watcha ma call it with a thinging ma bob

autumnwillow - the "side tube" is called a barb

Kurt


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## autumnwillow (Jun 27, 2018)

Haha

Lino it really is an erlenmeyer with a side tube! Hehe. See this thread http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=56&t=26859
I don't think its proper to call it a filtering flask because it shatters when used in a vacuum.

Cuchugold, they were not talking about reactors but mostly about atomizing. I did enjoy the thread though.


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## 4metals (Jun 27, 2018)

The best reaction vessels are the round bottom flasks with a 4” conical head. A versatile size for a small refiner is 12 liter. Even my big old fat hands can reach into the bottom of the flask. They require a heat mantle for heating and accept clamp on reactor heads which allow you to attatch condensors and tubing. 


They come in 12 and 22 liter sizes and both sizes are easily lifted to empty them. The 50 and 72 liter sizes are too big to lift and are usually mounted on a stand allowing the vessel to be poured out by pivoting on a center pin.


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## 4metals (Jun 27, 2018)

The heads that clamp on will fit every reactor with the same size 4” conical head. The photo in the post above clearly shows the clamps that keep the head on while a reaction is going on. This is what the heads look like. 


The top fitting gets a plug which is removed to add acids, the side angled fitting is for the condenser attachment. I have them made so the condensate return drips into the head and doesn’t run down the side of the head. If the clamp isn’t on right, the condensate can leak out if it runs down the inside. The return extension fixed that. 

I like to use flex teflon hose to connect the condenser to the head. It allows the condenser to be permanently mounted on the wall and never have to be moved once set. Solves a lot of breakage issues. The flex hose is visible in the first photo in the post above. 

Some refiners set these reactors up in the open connected to exhaust ducting and some put them in hoods. If you can add the acids cold and allow the reaction to cool off (usually overnight) then the funes are not bad and you can get away without a hood. If you are in a hurry then use a hood.


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## snoman701 (Jun 27, 2018)

4metals said:


> ]



I do love when you start sharing pics of well made equipment. It humbly reminds me of where I've been, and the direction I'm heading.

The transition from small bench size glassware to pilot size batch processes is tricky, and difficult to get used to. Everything seems to be about patience and organization of the process and the space. Seemingly big errors can be a small hiccup and seeming small errors can be huge setbacks.

Thanks!!


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## snoman701 (Jun 27, 2018)

Actually, thinking....

Do you have any photos of the area where you dump your reactors? And likely set up to filter? This is the area I have the most difficulty envisioning.

Right now I am doing my digestions in the hood, but when it comes time to filter or pour off, it has to be done on the floor. As much as I hate to admit it, my arms are wearing some nice brownish purple stains today from some splashback. Very frustrating, but I know that this is the "area" where I need the most work.




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## 4metals (Jun 27, 2018)

Well there are plenty of small to medium sized refiners out there using Buchner funnels and vacuum jugs. The down side to this is the lifting of the full vacuum jug, most are 5 gallons of heavy, wet, slippery glass which contains all of your dissolved gold. The potential for disaster always concerned me and I came up with a viable option. 

The solution needs to be transferred to a funnel and tabletop Buchner funnels work best. The system that I have made and installed in a good number of refineries requires a strong vacuum. Basically you pull a strong vacuum into a receiver vessel which is elevated above the hood. The solution is sucked through the Buchner funnel and into the receiver. When the receiver is full, the vacuum shuts and the jug is vented and the solution is drained out the bottom into the vessel where you will drop your gold. There are safety measures to prevent overfilling and a spray rinse system to rinse the equipment clean after use so it doesn't hold values. This is what the unit looks like on top of a hood before it is installed and plumbed.


The bottom of the vessel is visible inside the hood so you can see when it is filling or empty.


This is the unit filling from a funnel below with water as a test run.


And this is the spray rinse after draining


The reactor in a walk in hood with the vacuum receiver on top of the hood looks like this


What isn't showing is the cart mounted tabletop Buchner funnel which fits under the reactor when it is tipped to drain. The acid from the receiver drains out the hose you can see hanging which is directed to whatever you want to drain into for the next step. These units are also used to decant off the spent acid once the gold is dropped to separate the waste from the precipitate. 

I have built these units as small as 22 liters, the photo's are of 72 liter flasks, but I installed a 200 liter QVF receiver 25 feet above the floor in the center of a refinery once and there was never any problems with the liquids filtering quickly and ascending the tubing up to the receiver. 

The receivers are never left with acid for long periods, they are drained when filtration is complete so the hoses and valves spend most of their life without chemical exposure so their life is quite long.


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## snoman701 (Jun 27, 2018)

Mind....blown

Thank you so much


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## snoman701 (Jun 27, 2018)

It's not so much that it would apply to my situation as it is seeing an awesome solution to a real problem. When you consider the value contained in a 4 liter flask or even 12 liter full of pregnant leach, the overhead of setting up a slick system like that is minimal. 

I am stuck at this point where I'm beyond the scope of my glassware for my feedstock, and seeing solutions like this help me think outside of the box we normally place ourselves in. 


So one of my other sticking points is the transfer of thick slurry like filter cakes such as silver chloride, or cemented values from dirty solutions. It seems that the process of cleaning the Buchner leaves me with as much supernatant as I started with! Granted, I can use toilet paper to wipe with, so I transfer it on a medium that breaks down instantly....but, got any slick tricks for that?? 


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## 4metals (Jun 27, 2018)

Another option is a double diaphragm pump powered filter and transfer unit. These are quite versatile and look like this;


These work by using the pump, which can run dry without any issue, to pull a vacuum which pulls the solution through the filter paper and pumps the discharge to wherever you put the hose. They are on wheels and can roll all over the shop. A few more pictures


The filtration grate is supported on its edges by the supports and in the center by the round rod, in place the filter support grate looks like this;


The 2 "hooks" slip into small slits which allow the plate to be removed for cleanup, they are not in place when the filter paper is installed. 

The suction is not strong enough to quickly seat the paper and hold it in place like a vacuum pump does so the paper is set on the support grid and a rubber gasket is pushed between the gap above the paper and below a welded in place ring to seat the paper. Setup takes only a few minutes. This is the gasket being positioned.


These filters come in a lot of different sizes and are available from Italimpianti. Very versatile filters serve many useful refining purposes.


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## snoman701 (Jun 27, 2018)

4metals said:


> Another option is a double diaphragm pump powered filter and transfer unit. These are quite versatile and look like this;
> View attachment 3
> 
> These work by using the pump, which can run dry without any issue, to pull a vacuum which pulls the solution through the filter paper and pumps the discharge to wherever you put the hose. They are on wheels and can roll all over the shop. A few more pictures
> ...



Those are beautiful, but likely cost 2x the cost of the car I am driving! 

So with the glass receiver....have to ask after letting it sink in for a few....did you work on a dairy as a kid? It's almost identical and I'm a little embarrassed I didn't make the connection sooner.


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## 4metals (Jun 27, 2018)

For dirty solutions that don't filter well I like a centrifuge. But not the test tube type. This is one unit which spins a pair of 1 gallon vessels. 


Fill the 2 containers equally to balance it and spin for 15 minutes and a solution of acid and jewelers sweeps comes out with the sweeps pinned to the bottom and the liquid is easily poured off. The same is true for many difficult solutions. 

Another handy trick I discovered for a small shop is to raise your waste acid pH to 9.5 with caustic, put it in the centrifuge and spin. Shortly you can pour off the clear water and have this;





They make a larger unit with a liquid capacity of 50 liters which I recently priced at 16,000 euro's. That will filter 13 gallons of solution in 15 minutes and even do waste treatment for a moderate sized shop. The manufacturer has a video on his site of the larger unit working.http://www.emakmakina.com/products/...ecanter-centrifuge-system-fast-precipitation/


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## 4metals (Jun 27, 2018)

> So with the glass receiver....have to ask after letting it sink in for a few....did you work on a dairy as a kid? It's almost identical and I'm a little embarrassed I didn't make the connection sooner.



Never worked on a dairy farm but I have friends and close neighbors who have working dairy operations. But now I will be making it a point to go to see their operations.


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## snoman701 (Jun 27, 2018)

4metals said:


> > So with the glass receiver....have to ask after letting it sink in for a few....did you work on a dairy as a kid? It's almost identical and I'm a little embarrassed I didn't make the connection sooner.
> 
> 
> 
> Never worked on a dairy farm but I have friends and close neighbors who have working dairy operations. But now I will be making it a point to go to see their operations.


We had a very similar receiver system on the dairy I worked on. It had a vacuum trap and a receiver. The vacuum trap was just a glass receiver vessel with a float valve in it, it kept milk out of the vacuum lines. It was fed by stainless lines that ran through the milking parlor. The reciever itself was about a 12 gallon flask that had a float switch that would trigger a pump to pump the reciever to the stock tank. 

At the end of the milking you would turn off the pump, then milk your cows that recently calved. This milk couldn't be shipped with the rest of the herd and was used as feed...but it had a bottom drain valve (actually just a rubber cap) that would release as soon as you turned off the vacuum pump. 


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## 4metals (Jun 27, 2018)

I keep the liquid out of the vacuum lines by using a high level float to shut off the solenoid supplying the vacuum and open up another solenoid to vent the vacuum and all incoming flow stops immediately. You can flip a switch to start suction and when you are done flip the same switch off to shut it off. If you don't notice it and the receiver gets full, the float triggers the same function as the switch and it shuts down. 

Having a good vacuum system enabled me to set up systems to simplify filtering and also have acids on tap in the hood and eliminate acid pumps. More time refining and less time pumping and cleaning up spills.


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## snoman701 (Jun 27, 2018)

Did you make use of an aspirator type vacuum pump? Or some other type? The last refinery I worked in used a Hayward pool pump of all things, along with a cone bottom tank feeding the pump directly. The cone bottom tank had a pvc bar across the top with three simple $20 nalgene aspirators, spraying towards the bottom of the cone. 

No solenoid valve to keep the lines dry though. Always had to remember to kill the vacuum first. 


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## snoman701 (Jun 27, 2018)

4metals said:


> Having a good vacuum system enabled me to set up systems to simplify filtering and also have acids on tap in the hood and eliminate acid pumps. More time refining and less time pumping and cleaning up spills.



Acids on tap....I like that! 


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## 4metals (Jun 27, 2018)

> Did you make use of an aspirator type vacuum pump?



The vacuum pumps work by pumping water through an eductor to pull the vacuum so essentially a powerful aspirator pump. The units I had fabricated were essentially a pump, eductor and a box of water. This is one set up.




It is a fancy professionally fabricated version of this thread;http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=4640&p=39885#p39885


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## autumnwillow (Jun 28, 2018)

Amazing posts 4metals, as always. Snoman has asked most of the questions that I would have asked.

In the reaction vessels I see that they are closed and have no entry for air. With a vacuum regulator you could control the pressure if the reaction is weak to prevent shattering the reaction vessels but if the reaction is strong (eg atomized materials) how would you control it? The gasses would either push the conical stoppers and leaking starts. I would assume the operator has everything controlled somewhat somehow.

In my small setup, the only way I could get this to work is by replacing the condenser with a bigger one and larger diameter hoses for higher CFM output along with a small entry for air in the reaction vessel. Before I was having problems with the condenser not even working because the vacuum pressure was too high that it was already pulling the liquid it condenses to the scrubber unit.

I was always trying to figure out how to remove the liquid/solids from such big reaction vessels, I always thought that it could have been by inserting a vacuum hose and continuous washing or through a bottom drain. There is no way I am going to lift a 12L vessel full of gold liquid. That is just a risk I cannot afford! Even this 4L flasks that I am working on with right now, I know sooner or later I might bump it somewhere and could end up shattering it. As long as its moving there's a risk. I would either go for that tilting device or a bottom drain.

How about using PP filter cartridges for AR liquids?
How about stirrers? I believe the best reaction vessel should have its contents agitated without breaking the actual vessel.


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## 4metals (Jun 28, 2018)

> In the reaction vessels I see that they are closed and have no entry for air. With a vacuum regulator you could control the pressure if the reaction is weak to prevent shattering the reaction vessels but if the reaction is strong (eg atomized materials) how would you control it? The gasses would either push the conical stoppers and leaking starts. I would assume the operator has everything controlled somewhat somehow.



The reactor is not closed, the top of the condenser is open to the exhaust ductwork and I have never seen too much pressure build up to pop out the glass stoppers. When processing reactive material with high surface area, the rate of the reaction is controlled by the rate of chemical addition or the feed of the material. One of the benefits of a spherical vessel is as a reaction rises the shape seems to push the rising foam into the center and knock itself down. Of course if you overdo it you can overflow any vessel. These reactors are never filled more than 60% of capacity, so a 12 liter flask will never be filled with more than 7 liters of acid, really not too heavy to manually handle. They even make a 5 liter vessel that takes the same heads, that is lighter and I usually use them for platinum stone removal lots. 

The airflow out of these reactors through the condenser is quite low and if you vent it by loosening a glass stopper the flow will increase. If you come in to your shop in the morning after a reaction was run the night before, the fume will be visible in the vessel and the connection to the condenser because there is very little fume escaping even though the condenser is open to the vent. By removing the top glass stopper, the airflow immediately evacuates all of the fume up through the condenser. 



> How about using PP filter cartridges for AR liquids?



I am not a big fan of poly wound cartridges, they are difficult to rinse free of values and by their very nature they are contained in an opaque cylinder so you cannot keep an eye on the filtration surface. To recover any values they must be incinerated and the ash processed. And they do not exactly burn with a clean smoke free stack.



> How about stirrers? I believe the best reaction vessel should have its contents agitated without breaking the actual vessel.



I have used these vessels extensively for karat gold refining and stone removal. With karat gold I always made sure the silver content was as low as possible, never above 9%. This will allow the acid to react and minimize gold trapped in the chlorides without stirring. 

As far as diamond removal, never stir the reaction. When I first started doing stone removal chemically, in the early 1980's, I thought stirring would be good. It actually makes good sense because you cannot control the assay so some pieces will have in excess of 9% silver. I learned the hard way that stirring causes the material to move about against the glass. With diamonds this meant they scrape against the glass and scratch it. This weakens the glass and eventually you pick up the vessel and the bottom piece, in the shape of a large watch glass, breaks out. Really quite the mess, destroys the mantle, gold recovery is a nightmare, not something you want to experience. 

Processing jewelers sweeps in aqua regia would benefit from a stirrer but I prefer to process sweeps in a titanium bucket and stir with a stir rod.


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## 4metals (Jun 28, 2018)

> Acids on tap....I like that!



Acid on tap is a real convenience! The drum of acid is stored alongside the hood and connected by tubing. (The tube entering the top of the reservoir in the picture connects to the acid drum.) A vacuum tube connects permanently to the reservoir and when the vacuum is turned on by opening the valve, acid is drawn from the drum into the reservoir. There are no float valves to prevent overfilling as that would be too complicated, instead I added a tee with a cap between the valve and the tubing connecting the vacuum to the jug. There is a cap on the tee with a 3/8" hole drilled in it. When you turn on the vacuum valve it still will not draw acid into the jug. You need to place a finger over the hole to generate suction. When you remove your finger the suction is lost and flow stops immediately. This makes the operator the safety valve because you have to stand there with your finger on the hole. The reservoir has a nice teflon and glass spigot to dispense acid into your measuring container. 

I like to set up a 5 gallon reservoir on one end of a tabletop hood for Hydrochloric and a 2 1/2 gallon reservoir on the other end for Nitric. 

The feed pipes into the acid drums have a built in water trap to burp under vacuum so the drum doesn't implode and the small moat of water keeps the acid from fuming into the shop.


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