Honest accident and need advice to fix

[Slaughlin79]

I’ve done this many times and I knew what could happen before it happened, so I just screwed up by accident.The other night I made some stannous chloride by adding my HCl and tin solder to my dropper bottle. By habit I screwed the top on forgetting like I said I already knew pressure was going to build.

Woke up the next morning and overnight the pressure rose causing the dropper bulb to bust. It was just a tiny pinhole and the solution that came out of that pinhole hit the bottom of the cabinets that are in the garage and then into 3 containers containing dissolved gold.

They are all aqua regia. Two have gold and the other one has gold and possibly other pm’. They also now have a bunch of tin. The solutions have turned pretty much black and no light will pass through at all.The one that got it worst,the solution itself seems to be a lot thicker than before. Also a white spoon I left in it is purple up to the solution line.

I’ve been reading through a lot of posts and it seems there are a few different ways to break a colloid. The Sulfuric acid method seems to be the simplest way but I don’t know for sure because I have no experience regardless of the method. Anyways The method I’ve read was boiling solution with sulfuric acid if I remember correctly and the metallic gold would drop out of solution?

I would like to hear from an experienced or knowledgeable member before attempting because the word boil is word that is sometimes used loosely and I don’t wont to lose any of my now gonna be harder earned gold. Thanks guys and gals

 

[Slaughlin79]

This is a couple pics I meant to post for reference.

 

[g_axelsson]

Try add a bit more aqua regia, i.e. add a bit nitric acid to the dark solution (do a test in a small sample first). When all the tin is oxidized it will start dissolving the colloidal gold and bring it back as gold chloride.

Just as a test I once dripped some stannous into a gold chloride solution. I still had some oxidizer left so all I needed to do was to stir it a bit to get the ruby red gold colloid to dissolve again.

You might have some issues with filtering, but that has been discussed a lot on the forum so I won't go into detail about that.

I have had a similar but not as violent rupture in a dropper bottle, I couldn't find any holes but some clothes nearby had clear marks of acid bleaching.

Pro tip : Get some proper beakers, it's so much easier to work with. :wink:

Göran

 

[Geo]

Agreed. Add more oxidizer until the solution clears. Enough oxidizer will overpower the tin.

 

[Slaughlin79]

Goran And Geo thank you both for replying. Haha I didn’t realize not one of my beakers are in the pictures, just mason jars and a candy jar.i learned the hard way when an Anchor 100ml glass measuring cup cracked all the way around while on top of a coffee pot heater with 2 pretty good size 14k gold rings that were almost fully dissolved and now I have what is the most expensive purple looking paint spill on top and down the sides of my cabinet.picture bellow. You are absolutely right they do make life a lot easier. I actually do have a handful of Pyrex but I will hopefully never buy another one as long as my new Kimbal beakerPlus beaker flask combo’ hold up. I absolutely love them things

Anyways when you mention about filtering the tin basically you are saying dropping the tin to a solid form to be separated from solution by filtering,correct or no bueno? Thanks again guys

 

[g_axelsson]

When tin oxidizes it forms either a hydrated gel or a fine powder, both famous for clogging filters. If you drop the gold without removing the tin it will mix with your gold powder.

I have no idea of how much you have in your beakers and which way is the best for you to deal with the tin, so I leave that one for you to research a bit first. Maybe you can get away with just let it settle, filter the clear liquid at top and then do a slow filtration of the last part.

As you know (and showed in your picture) a broken jar can cost you more than a whole set of nice beakers. Thicker glass is a lot more sensitive to heating than a thinner glass beaker. Beakers also have straight sides and a nice tip to pour from without spilling.

Göran

 

[Shark]

When tin oxidizes it forms either a hydrated gel or a fine powder, both famous for clogging filters. If you drop the gold without removing the tin it will mix with your gold powder.

I have no idea of how much you have in your beakers and which way is the best for you to deal with the tin, so I leave that one for you to research a bit first. Maybe you can get away with just let it settle, filter the clear liquid at top and then do a slow filtration of the last part.

As you know (and showed in your picture) a broken jar can cost you more than a whole set of nice beakers. Thicker glass is a lot more sensitive to heating than a thinner glass beaker. Beakers also have straight sides and a nice tip to pour from without spilling.

Göran

Thank you for a great reply. Tips such as this are the ones that point beginners towards future purchases for glassware. It even helps some of us that have been around the forum a while as well.

 

[Slaughlin79]

Thanks for the reply again Goran. I tried to jump straight in thinking I could do this right but soon learned it doesn’t work that way with this. Other things I can but this is so knowledge oriented you have to do your homework and lots of research and a question after because there’s so many combination of chemicals and metals and so much more with temperature and ph and how all these work together and apart. There just tons of stuff to learn and not for the lazy.

When that glass broke I was next to it and just by reaction I grabbed bare handed and tried to dump into plastic container I had near me and before I knew it,I had AR all over my hand. Honestly I was very surprised and relieved that it actually didn’t like burn me like I always thought acid would but it did stain my hand and eventually the skin dried up and peeled off. That was when I first started and it scared me enough to put it down and read more and build up a little bit of correct glassware.

The 3 containers have been sitting for at least a month and they actually seem to be settling. I didn’t think that was possible with purple of cassius bc it’s Nano and isn’t big enough to sink and will sit suspended forever literally? Am I wrong or are there situation when the rule does not apply?

One solution I took a sample and I added nitric and once it was solution cleared up I poured a little sulfuric acid in to see if I could get some tin to drop and when sulfuric hit the AR it sizzled. Like if you put cold water on something red hot. I can’t find anything on the reaction between AR sulfuric acid. Is it just bc of unused nitric that I added?

 

[Slaughlin79]

Well I added nitric and then added sulfuric which sizzled and to answer my own question from last post it had to of been the tin coming out of solution and the free nitric burning it back up.

Added sulfuric till it stopped (added in increments) filtered and took a tiny bit deluded the heck out of it probably at 1.5:1 water:solution and finally melted and poured a fresh copper bar and set it in. The process worked amazingly! Cleanest gold drop using copper to cement on to date. It’s amazing how a clean solution solves so many nightmares like No gold plating on glass and the precipitation is on the bottom of beaker and not suspended or worse floating right on top. It’s a small one but it’s a breakthrough nonetheless. I know that’s been by a little dramatic but that’s what it really is. I’ve had clean drops but none from solution like this so.......

Again thank y’all so much for schooling me a bit for some priceless nudges in the correct direction and a couple pics below.

 

[anachronism]

Dude why are you adding sulphuric to Nitric?

 

[Slaughlin79]

Dude why are you adding sulphuric to Nitric?

I added sulfuric and the next morning a bunch of white powder was on the bottom. It had to be the tin that dropped from a Stannous Chloride bottle that busted and sprayed a bunch in my gold chloride leaving me with a purple black mess. I read that you could redissolve with ar and then drop tin with sulfuric and it worked good or it seams to have. I dropped the gold with FS and didn’t get a hint of colloid. Its all explained up above. Thanks for replying

 

[kernels]

I think you probably mean you can drop lead by adding Sulfuric, which you only need a tiny amount of Sulfuric for.

 

[anachronism]

No problem, but as Kernels quite rightly pointed out you don't need much. Don't get into a situation where you've got a strong mix of the two during processing.

 

[Slaughlin79]

Well after a lot unnecessary and got to admit hard work and tons of patience that paid off,today I gathered my once big mess and gotta say I’m proud of myself for fixing.
But I know I wouldn’t have finished so quick if you guys hadn’t helped me out answering a few questions so thank y’all. And here’s a picture of the end result. Again thanks a lot.

 

[LT_golden]

Hi Göran and Geo,

Just as a test I once dripped some stannous into a gold chloride solution. I still had some oxidizer left so all I needed to do was to stir it a bit to get the ruby red gold colloid to dissolve again.

Agreed. Add more oxidizer until the solution clears. Enough oxidizer will overpower the tin.

Would hydrogen peroxide work for this oxidizing purpose?

By extension, would hydrogen peroxide also work for HCl+bleach (no nitric acid) with some tin and colloidal gold in solution to eventually break the gold colloids to precipitate metallic gold?

I’m imagining (hopefully not incorrectly) that hydrogen peroxide would work for both because of this:

Firstly, colloidal gold is also gold at oxidation state 0, in other terms metallic gold just as any gold nugget or coin. It might be covered by a layer of charged particles that repels the clusters so they don't coalesce into particles large enough to sediment at the bottom.

Hopefully I didn’t take this out of context.

Thanks.

 

[g_axelsson]

That should work but I haven't tested it.

Do you have problem with colloids?

Göran

 

[LT_golden]

Do you have problem with colloids?

We’re not even at that stage yet. LOL

But I suspect that I might. There were some components and PCBs that I didn’t process for tin as thoroughly as I should have, at the beginning of our recovering. Also, I think a couple of times when doing stannous chloride testing our leaching solution (just in case and out of curiosity), we put the few drops of solution back into the main solution because we saw some tiny gold flecks in it.

 

[LT_golden]

That should work but I haven't tested it.

Do you have problem with colloids?

You had to ask. :mrgreen: But this is exciting! Something new at every turn!

So I’ve been processing a small bundle of desktop-sized RAM sticks, soaking the entire sticks in HCl in batches in the same container, loosely covered, lightly shaken about twice a day. I was cleaning out the latest batch when I noticed that the solution appeared... greyish-purple?

I filtered to get a better look at the solution and the sludge. I performed pH and stannous chloride tests for sanity check.

Here’s a pic of the solution and the pH and stannous chloride tests:



Here’s the sludge, appearing to contain nickel and stannous oxides, and the blue seems to indicate cupric chloride:



Looking at the sediments still left in the original container, it appeared to contain some copper powder, and flecks of gold (not very apparent in the picture I’m afraid):



No signs of silver chloride, hence it was probably something else causing the color.

One suspect was of course colloidal gold in solution. Based on comments found earlier in this thread (add oxidizer until tin is overcome), I took out a 5mL sample of the purple solution and started dripping in 3% hydrogen peroxide. This happened while dripping, for each single drop:



The beautiful orange color would vanish as soon as it appeared, but every third drop of H2O2 would need slight agitation to make the color disappear.

I did some searching... could it be colloidal gold being oxidized by the hydrogen peroxide into gold oxide, which is an orange solid dissolvable in HCl? And then the gold oxide quickly loses its 3 oxygen atoms to the copper and tin in the solution? This would seem to explain that the solution seemed to turn greener and greener...?

I’m guessing here; there’s still so much for me to learn.

Then I started adding hydrogen peroxide to the sample, drop by drop. By the 40th drop, a deep, golden-orange color settled in and refused to go away even after continuous agitation. Just to see what would happen, I added 10 more drops but there was no appreciable change. Throughout the first 40 drops, the reaction was very slightly exothermic — I could feel by touching the outside of the cup that it was very slightly warmer than my hand.



Could it be that I had dissolved gold? Time for another stannous chloride test...

Uh, for some reason I couldn’t attach another image. Have I reached some kind of limit? I’ll continue in a following post.

 

[LT_golden]

Could it be that I had dissolved gold? Time for another stannous chloride test...

Stannous chloride tested negative for gold:




So what’s the purple? I thought it might’ve been colloidal gold in solution, with particles about the size of 90nm if this chart is believable:



It’s unlikely to be silver chloride, as there are no precipitates in solution; nor could it be silver oxide (black powder) which is supposed to be soluble in water (I’m only using 20% HCl).

Okay, more research and reading for me. If the gurus could help me with any idea of what’s going on, I’d really appreciate it, too.

Thanks!

 

[butcher]

If any gold ever dissolved it (was reduced) or cemented back onto the copper in the original leach.
The stannous chloride cannot test for colloidal gold, because the gold in colloidal form is already a metal in suspension.
I suspect that you are looking at a solution full of base metal ions (with iron in the mix)...

Shining a light through the solution is one way to detect colloids in solution (Tyndall effect).

Hoke's page 100 would be a good place to further your test on the solution...

https://www.google.com/search?q=colloidal+solution+Tyndall+effect&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi_7ZPj7LjeAhWSJXwKHbesBr0Q_AUIEygB&biw=1204&bih=865