Glass dish broke while bringing hcl bath to boil

Hey guys,
I ran into a bit of a problem while washing my first gold foil recoveries in hcl.
-I had the solution in a glass Pyrex (or so I thought) jar with the lid lightly on.
-I used a stainless steel mixing bowl with a bit more than an inch of sand from a spent concentrate gold mining trip, on a electric hot plate.

Everything was groovy until it almost reached a boil, then pop goes the glass. Most of the liquid dropped in the bowl, a bit splattered out with sand.

Lots of smoke started to fume so I unplugged the stove and went into the house. Had a fan blowing the fumes out of the partially closed garage. So it dealt with pushing the fumes out when it shattered.

Now I have the solution mixed with the fine sand and silt. Which I've tried panning and separating. But still can't seem to get everything.

Any suggestions on removing the foils from the sand?

Thanks!
Two pics attached of before. Didn't do an after.

PARKER113 said:

I had the solution in a glass Pyrex (or so I thought) jar with the lid lightly on.

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There's pyrex, and then there's pyrex. Measuring cups and many kitchen containers are made of "pyrex", but most also say they're not for stove top use, which is the same as a hotplate. They're thick glass, and when heated on a stove top or hotplate, the glass develops a lot of stress due to uneven heating, and as you experienced, they can fail. Lab glass is thin and heats more evenly. Well worth the money when you're dealing with gold.

I used a stainless steel mixing bowl with a bit more than an inch of sand from a spent concentrate gold mining trip, on a electric hot plate.

Everything was groovy until it almost reached a boil, then pop goes the glass. Most of the liquid dropped in the bowl, a bit splattered out with sand.

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Good that you had your pyrex vessel in a secondary container. Bad that is was stainless steel when you were working with HCl, which will eat stainless. The generally preferred material is pyroceram / Corning ware.

Lots of smoke started to fume so I unplugged the stove and went into the house. Had a fan blowing the fumes out of the partially closed garage. So it dealt with pushing the fumes out when it shattered.

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The smoke was probably the HCl attacking the stainless steel. Bad choice. The much worse choice is refining in your garage. The fumes will destroy anything in the garage, and if it's an attached garage they WILL work their way into your home, poisoning everyone inside. Never work in your garage.

Now I have the solution mixed with the fine sand and silt. Which I've tried panning and separating. But still can't seem to get everything.

Any suggestions on removing the foils from the sand?

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No suggestions until you find somewhere else to work.

Two pics attached of before. Didn't do an after.

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I don't see any pictures.

Dave

Thanks for the reply! Great info.

I am able to work outside. But since this is a small test amount there isn't a ton of fumes. And the fumes get ventilated out well. Except when accidents happen and that's why I wear the safety gear as in proper ventilator, goggles, long rubber gloves and rubberized apron.

I should of done a test run with water first.
I now know to use a corningware hot plate with lab glass or a thinner style Pyrex vessel. And test it with water!

Now the real test is getting the gold out of the sediment.

Any advice will be appreciated.
I'll post some pics of the progress I made last night with panning and a suction tube.

Here's a few containers of water that it's in and the beaker of collected foils with a smaller amounts of sediment.

After you find an appropriate hood, you need to dissolve the gold foils in AR and then precipitate it

Thanks Lino.
I pondered that. But then I figured the sediment might clog the filter after dissolving the gold and filtering it.
I've tried filtering a few mls of the top layer through a filter and it took a whole night.

Are you thinking that the AR will change the state of the muck enough to either pass through or stay in the filter?

Since I'm dealing with a small amount of sand and gold foils (20 grams of pins /fingers worth of foils) is it necessary to need a hood set up for this? Or will outdoors suffice?

Thanks for your reply!

You can decant, then add water, mix, decant again. Filtering is not a must. About hood - I hope I can leave it to your (and your neighbors' if any) judgment

Sorry to hear about the accident, but you have been given good advice above.

The smoke were most probably HCl boiling off the setup, the sand had a temperature above the boiling point of the acid so when the vessel broke some of the acid instantly boiled when it mixed with the sand. The HCl mist coats every surface it comes in contact with, especially cold metal surfaces. You will see a lot of rusting of tools, nails... and so on in the garage now. That is why we always advice against indoor refining without a proper fume hood that can deal with disasters like this.

Then, why boiling foils? Yeah, they are dirty but the small reduction of base metals isn't worth it, just go straight to AR and then filter off garbage and precipitate the gold. The gold powder on the other side should be washed to remove that last trace of base metals.

Gold foils are impossible to pan, they have so much surface area so it doesn't behave as placer gold. As Lino said, dissolve in aqua regia, decant / filter off the solution, wash the sand with water and add to the gold chloride.
I would incinerate the sand first though, if it contains organic debris it might absorb some gold chloride.

Göran

Lino1406 said:

You can decant, then add water, mix, decant again. Filtering is not a must. About hood - I hope I can leave it to your (and your neighbors' if any) judgment

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That's great advice. Decanting will be much easier than filtering. Although I would still need to filter the solids after Decanting it from AR (I hope hcl/cl will give the same result)
I've done a decent amount of research which is why I'm doing these acquaintance tests with small amounts of everything. I've leaned a lot from members on here in their posts and am looking forward to learning more!

g_axelsson said:

Sorry to hear about the accident, but you have been given good advice above.

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Thanks for the reply Goran!

The smoke were most probably HCl boiling off the setup, the sand had a temperature above the boiling point of the acid so when the vessel broke some of the acid instantly boiled when it mixed with the sand. The HCl mist coats every surface it comes in contact with, especially cold metal surfaces. You will see a lot of rusting of tools, nails... and so on in the garage now. That is why we always advice against indoor refining without a proper fume hood that can deal with disasters like this.

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Yeah it was quite the situation I how long will it take to see the corrosion?

Then, why boiling foils? Yeah, they are dirty but the small reduction of base metals isn't worth it, just go straight to AR and then filter off garbage and precipitate the gold. The gold powder on the other side should be washed to remove that last trace of base metals.

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I was boiling them just to get acquainted with the whole process. As I recall it's wise to wash firsts to remove base metals.

Gold foils are impossible to pan, they have so much surface area so it doesn't behave as placer gold. As Lino said, dissolve in aqua regia, decant / filter off the solution, wash the sand with water and add to the gold chloride.
I would incinerate the sand first though, if it contains organic debris it might absorb some gold chloride.

Göran

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Thanks for the advice! I will attempt this outside away from people and metal. As I'm sure there could be a decent reaction with the sand and the hcl/cl. Probably a bit less than a pound of sand.
I'll post a reply with the results when it's compete.

Cheers!

Hey guys,
Thanks again for the advice! I did just that, treated a large jar with the sand and a smaller jar from the test tube with Hcl and Clorox.
I don't think I added enough Clorox the first time or waited long enough, as after decanting/filtering I could still see some small foils and gold particles. So I did the process again with a bit more Clorox. And it turned out better. (I did the large jar last night and small today, had problems with the small batch/jar)

I proceded with dropping the gold with Smb after I filtered the last bit of the gold bearing solution and spraying down the sides of filler with water. Guessing there is 2 grams of gold each. I put in aprox 2 grams of dissolved Smb in each batch

Starting on the large batch, I put in the first few drops of Smb and noticed brown precipitate particles dropping around each droplet. After putting in aprox 2 grams (scale sucks) and stirring in a period of 10 min some nice brown conglomerates were starting to form.
My question is do I continue adding Smb until I see no more clouds forming from the drops? Then test?

With the smaller batch the droplets weren't clouding nearly as much. I would assume the bleach hadn't had enough time to evaporate. Or it's lower gold quantity which is doubtful.

I am letting them sit overnight to settle and will add some more smb in the morning to check for a reaction. To be honest my stannous chloride hasn't come in yet lol.

I will decant and save solution and filter the gold out. Let it dry and prep the smelting stage which will be tomorrow if all goes well.

Looks like a bit more precipitated throughout the night. But I was expecting double the amount. Should I add Smb until the solution turns clear?

Thanks!

You should test it with stannous chloride to see if any gold is left in solution. (This will also help keep you from wasting your chemicals.) Then if you need it ( test shows positive for gold) you can add a small amount of smb.

As I mentioned above, those measuring cups are not well suited for refining. If you try to heat them, there's a good chance they will break like your first jar.

Dave

Hi Dave,
Yeah I won't be heating them up on anything that's for sure. They're just holding containers. I still need to acquire a the appropriate dishes for heating and boiling.

Do you have any input as to weather the gold is precipitated even though the solution is still not clear? I know it should be tested. And it will when it comes. But for the time being I'd like to melt today if possible. Although I have no means to give it a wash just yet..

Peter

Shark said:

You should test it with stannous chloride to see if any gold is left in solution. (This will also help keep you from wasting your chemicals.) Then if you need it ( test shows positive for gold) you can add a small amount of smb.

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Thanks Shark!
Yeah I'm still waiting on it to be shipped. But I figure if need be I can process what I have and test and drop when I get the stannous chloride.

Peter

One more thing, and kinda off topic. I'm having doubts on my melting equipment. I'll take a pic but I think the crucible may be to small and the flame on the torch too big.
I attempted to coat the crucible with borax but the flame pretty much hits the whole surface at once. Still I sprinkled a few pinches on all sides, after heating it up quite a bit, then got it to red hot. Doesn't look like the video yet lol.

But I was expecting double the amount.

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That seems to be the norm for people starting out.
Take the advice the others have shared with you, the Gold isn't going anywhere unless you throw it away or spill it again. You can make your own Stannous Chloride for testing. Be patient.

Claudie said:

But I was expecting double the amount.

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That seems to be the norm for people starting out.
Take the advice the others have shared with you, the Gold isn't going anywhere unless you throw it away or spill it again. You can make your own Stannous Chloride for testing. Be patient.

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I would think so haha. Thanks Claudia

I make my stannous from fishing sinkers. Here is some info on them, but I usually get them at Wal-Mart.

http://www.watergremlin.com/my-tacklebox/tin-round-removable-split-shot/

There are many ways to make stannous, and a mind boggling amount of info can be found all over the forum.