Sealed Reaction Vessels

[Rag and Bone]

I have been experimenting with sealed reaction vessels. So far I have used sealed primary fermentor buckets and acrylic food jars with gaskets for acid-peroxide and acid-clorox.

:!: :!: :!: D A N G E R (not a recommended method, spills and explosion are possible with vessels under pressure)

Would the fumes of AR or Nitric be viable in the same conditions? :?:

Would any recovery/refining processes be hampered by pressure? :?:

 

[Noxx]

Every processes I know that dissolves, leach gold or other metals will produce some fumes, whatever it is Hydrogen, Chloride or NOx.

NEVER seal any vessels containing AR, Nitric Acid (if your dissolving), HCl-Cl, HCl-Peroxide (if dissolving)

 

[skippy]

There was a thread where people were reporting using pop bottles for HCl-Cl reactions, and from what I gathered the hydrogen diffuses through the bottles. You wouldn't want to be processing anything that would react too vigorously with the HCL acid part, because the hydrogen might be evolved too quickly for diffusion. Besides that make sure that the reaction won't produce more chlorine than the headspace in the bottle can safely contain (not too high pressure) and you *should* be OK. Plastics tend to lose strength dramatically at elevated temperature, so keep the temperature from rising.

Obviously one should be cautious though, and maybe pressurizing a (20L?) fermenter is treading on possibly dangerous ground, given that they arn't meant for pressure usage. Perhaps it would be a good idea to treat your vessel as if it *will* fail and to take appropriate precautions.


As far as the original question goes, I wonder what the point would be of pressurizing the vessel. Pressurizing Hcl-Chlorox would prevent chlorine loss, and increase the concentration of chlorine in solution, whereas aqua regia's action is due to attack by ions (correct me if I'm wrong on that) which won't be helped by pressure. Not only that but it would be quite nasty if you suffered a reaction vessel failure and got a sudden release of built up NO gas. Very bad stuff.

 

[Rag and Bone]

I started using these to refine without fumes. So far it's working OK. I'm running small batches of AP and AC with plenty of head-room. I keep the the vessels in buckets with lids in case something goes wrong. I approach them carefully with full safety gear. (reminds me of a failed batch of home brew that was blowing the necks off the bottles :shock: what a mess)

The primary fermenters are plastic (not a glass carboy) and can handle quite a bit of pressure.

 

[OMG]

Let us know if you find out that the AC works better under pressure. I assume it would, but I'm wondering by how much.

 

[Rag and Bone]

In my experience, AC is really slow (even with heat and constant agitation). Others have better results, notably Lazersteve.

I currently have some gold foils from 100 P1 laptop cpus in AC. I'm adding a dash of clorox every 24 hours. So far it's coming along nicely. There appears to be quite a bit of silver chloride. I'm considering covering it with ice and insulation after the next clorox addition to increase efficiency. The solution does noticably get warm so I'm keeping the additions small ~10ml

I also have pins from 100 old industrial switches in AP, sealed. (the plating is crazy thick!).

The only fumes I can detect emit when I add fresh chemicals.

I'm really wondering if a person could do AR in a sealed vessel. Set it up and just leave it. No scary fumes to worry about. Perhaps a small beaker with AR in the bottom of a large fermentor bucket, sealed.

I hope this discussion doesn't prompt anyone to do anything stupid. I know it goes against one of the key safety issues to bottle up active chemicals. [/code]

 

[lazersteve]

Rags,

You'll have much quicker results dissolving foils if you add 20 mL every 5-10 minutes with lots of stirring. I can dissolve gold foils very rapidly with HCl-Cl. The key is to keep it bubbling and keep the foils stirring. Heat is not required with foils, but helps with powder (especially dry powders). For batches of less than 10 grams, the foils will be dissolved in a single dose of clorox.

Steve

 

[Rag and Bone]

Steve,
I was misleading. The foils are not actually foils. Each cpu had a square plastic tab with gold wires attached. I'm trying to put them straight into solution. In retrospect, I would have stripped them in AP first, they contain more base metals than I imagined (the auric chloride is very dark ).

I'm switching to AR for powder. I found a cheap source of Nitric locally. I'll keep using AC for foils.