I can't tell if I messed up or what???

[Grelko]

I'm wondering if anyone could shed some light on this for me? I've been trying to find an answer on here for the last few days.


In the first jar was, the dirty gold powder from the original button that I dissolved in this thread. I had kept it in a mason jar for a while, still in the solution it was precipitated in. The lid rusted and iron possibly got into it. (approx 0.7g dirty powder, that came from IC chips)

I had a second jar with AP in it (lid rusted also, possible iron), that had approx 31g of mixed material.

The material/powder in the second jar, started out as a mix of...

9g of dirty powder left over from ~4lbs plated pins
~1g from ~3/4 pound gold fingers
Around 1 pound of small plastic/mylar strips that come off the side of a flat screen TV "screens", which have gold fingers incased in plastic or glue) After incinerating, the strips weighed ~22g

After filtering the jar with AP in it, the total material from both jars combined was ~7.8g

I put the wet filter with the powder/material into a melting dish. There was a little plastic/glue left in it.

I added some borax, then began to re-incinerate, but ran out of fluid about halfway through. Some of it barely melted and I know some of the coffee filter was still in there "burnt".

I don't know why, but I decided to try and dissolve the material with HCl/Cl.

Made a fresh batch of stannous, and tested the solution. Negative. Added a couple more mls of Cl over the next couple hours. Still negative. The solution was VERY dark green. Total amount was approx 20ml HCL, 30ml CL.
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I came back the next day and tested the solution. Negative. I'm guessing there was alot of copper etc., still in it and a possibly a tiny bit of iron, which pushed out any gold.

I filtered the material and put the negative solution into my stockpot, just incase there actually "was" anything in it.

I used a separate beaker for the powder/material. Not sure of the weight for this, which now also has some burnt filter in it.
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Day 3, I tried HCl/Cl again, slightly lighter green solution. Stannous positive for gold finally. I filtered the solution, rinsed it down and tested it again. Negative. :?: Ok, I must have diluted it too much.

Approx 50ml HCl, 50ml Cl and ~60ml tap water. Total solution ~160ml.
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Day 4 (today) Tested negative. I figured I would try to drop the material out, to see if I did have any gold that was getting a "false positive" from iron etc.

I put sand on my hotplate, to evaporate the solution from 160ml to ~75ml, to remove the CL so the SMB works. (Hotplate with sand worked really well)

Stannous showed positive again. It looked extremely black, so I let it sit there for about 10 minutes and rinsed it off. Nice purple stain

After the solution cooled back down, I took SMB and added maybe a gram or 2. (I'm guessing there was around 3-4g of gold in the material)

Tested with stannous, positive. Added another couple grams of SMB, still positive, a couple more... STILL positive :?:

I continued to get a positive for stannous "purple/black on paper towel and on spot plate", even AFTER the SMB stopped giving a reaction "I added about 1 gram after that also". There was a strong sulfur smell coming from the solution. (the smell burns the eyes and nose a bit if anyone was wondering, actually made me sneeze, so I went out into the yard for a few minutes).

Total SMB used was between 12-15g.

I've been thinking, that since the solution was ~160ml, and ~50ml of it was Cl, when I evaporated it to 75ml, if all of the tap water evaporated, there could still be up to 25ml of CL in it, which might be why it took so much SMB, and still shows positive for gold. Unless it's a false positive.

I gave it about 5 minutes and checked with stannous again. still positive, but this time when I used stannous , it also made an oily blue/black "grease?", that stays on top. (I have no idea what this is, possibly micro pieces of the burnt coffee filter floating on top?)

The solution is now orange-red and theres a light brown/yellow precipitate at the bottom. Looks almost like the clean gold powder precipitate in other threads.

I couldn't possibly have THAT much gold in there could I?, It has to be iron or something also? (I highly doubt there would be any PD or PL in it) There is about 1 inch of solution in the beaker and 1/2 inch of it is the brown/yellow precipitate.

I only let it settle for a few minutes, when I saw that mass of brown/yellow precipitate, so I may be mistaken on the amount. It looked like a lot.

I'm letting the solution settle for a day. There is probably alot of salt at the bottom mixed in with any gold that dropped making it look like more, since it may have been completely neutralized from adding SMB until it stopped reacting. "Even though the solution still shows positive for gold"

Anyone have any ideas?

I'm thinking about evaporating it dry and starting over with fresh AP.

The left over material, that was in the 3 filters, still has un-dissolved pieces of metal in it, which looks like alot of previously burnt filter paper "powder" and tiny gold copper flakes.

Once I get more fluid for my torch, I may just melt everything and start over. I'm going for 999 :mrgreen:

 

[Geo]

On day two, when you dissolved the solids, did you dissolve all the solids or did you stop when you had a positive for gold? When you filtered the solution, was there any solid metal that you filtered out? Gold can cement out on iron really fast, even before it can pass through a filter. Day three, it sounds like you still did not dissolve all the metal. A simple rule for putting gold into solution, you must dissolve all the metal in the mix or the gold will not stay in solution. Go back and check the solids. Be sure to dissolve everything that will dissolve. I think you are stopping the dissolution short each time and allowing the gold to cement out of solution before you have a chance to filter it.

 

[Grelko]

On day two, when you dissolved the solids, did you dissolve all the solids or did you stop when you had a positive for gold? When you filtered the solution, was there any solid metal that you filtered out? Gold can cement out on iron really fast, even before it can pass through a filter. Day three, it sounds like you still did not dissolve all the metal. A simple rule for putting gold into solution, you must dissolve all the metal in the mix or the gold will not stay in solution. Go back and check the solids. Be sure to dissolve everything that will dissolve. I think you are stopping the dissolution short each time and allowing the gold to cement out of solution before you have a chance to filter it.

I think that might be what I did. Maybe not enough HCl in the beaker before I use the Cl. Not everything was dissolved in the first place.

The left over material that I still have in the filter has tiny flakes of gold/copper pieces in it. It looks like there's a lot of ash in it also "grey/black powder from the burnt filter"

Edit - the black powder could be gold also.

I was keeping that separate for now and trying to figure out what I did to the solution. Then finish dissolving the rest of the material afterwards.

Edit -

Gold can cement out on iron really fast, even before it can pass through a filter.

That would explain a lot, thank you. I wasn't sure how quick it could cement out. I figured it would have already passed through the filter.

 

[g_axelsson]

A couple of things...

* Incineration doesn't need borax. Only use borax when melting (or washing).
* SMB doesn't drop gold. It is the SO₂ that precipitate the gold. To get SO₂ you need enough free HCl or the SMB will only dissolve, doing nothing.
* Carbon (from partly incinerated filter) will absorb gold chloride. You need to make a complete incineration before going to aqua regia.

Göran

 

[Grelko]

A couple of things...

* Incineration doesn't need borax. Only use borax when melting (or washing).
* SMB doesn't drop gold. It is the SO₂ that precipitate the gold. To get SO₂ you need enough free HCl or the SMB will only dissolve, doing nothing.
* Carbon (from partly incinerated filter) will absorb gold chloride. You need to make a complete incineration before going to aqua regia.

Göran

I must have gotten mixed up the on day I tried to incinerate it. I may have been trying to melt it. I was working on a lot of other things "melting etc" that day also.

That's probably why it still shows positive then. I might have evaporated enough of the HCl to have the SMB not work.

I was trying to do this without AR, I was going to "completely" incinerate the material as soon as I got another bottle of fluid for my torch. Possibly just melt it into a bead, flatten, grind and re-dissolve with HCl/Cl again.

I'll definately be refining it atleast 2 more times because I know it's very dirty still.

 

[Barren Realms 007]

If you had 7g-8g of gold dissolved in the amount of solution you have you would not be getting a purple stain on your stanous test. It should show up as a black stain with that concentration. Also with the amount of solution you have and the amount of SMB you have added you will most likely be showing a false positive test.

 

[Grelko]

If you had 7g-8g of gold dissolved in the amount of solution you have you would not be getting a purple stain on your stanous test. It should show up as a black stain with that concentration. Also with the amount of solution you have and the amount of SMB you have added you will most likely be showing a false positive test.

The material itself was 7-8 grams (not all of it was dissolved, so I'm sot sure how much would be in solution). I think i might have 3-4 grams of gold in the solution and filter combined. Stannous showed up black "purple stain", but still shows black after all the SMB. I must be getting a false positive, maybe from the burnt paper or dissolved iron, if there's any in there?

I don't think I could get a false positive from the burnt filter. I might just be reading it wrong because of the oily black/blue grease that sits on top after I put in a drop of stannous.

If I get a chance to work on it later, I'll take a couple pictures.

 

[Geo]

Can you show a picture of the stannous test and one of the stain left after.

 

[Topher_osAUrus]

I don't think I could get a false positive from the burnt filter. I might just be reading it wrong because of the oily black/blue grease that sits on top after I put in a drop of stannous.

Put in a drop of stannous?

How are you testing with stannous? In a spot plate?

How you phrased that makes it seem like you added stannous to the entire solution?

Use a spot plate or cotton swab.

 

[Grelko]

I didn't get a chance to work on it since it's raining now, but I was able to get a few pictures earlier.
I forgot to take a picture of the stain left afterwards.

I'm using a spot plate and last night I used a spot plate and paper towel.

I'm thinking that the precipitate has alot of salt mixed in.

Picture 4 has a small reflection, but it looks like oil streaks on top. In the sunlight, it looked very dark purple/black.

Could it be possible, that since I ran out of torch fluid, any little bits of plastic ended up melting into bio-diesel instead of turning to ash, leaving the oil streaks on top? Or, maybe even carbon residue from the partially burnt filter paper?

Edit - Actually, could the oil streaks be from borax re-dissolving when I evaporated the solution? It is laundry "soap" after all and looks like soap film on water. (20 mule team borax) sodium tetraborate.

 

[Geo]

Decant what solution you have to another beaker and rinse the powder. Add the rinse into the decanted solution. Heat the solution to steaming and see if you get any reaction or color change. After an hour or so, turn off the heat and let the solution cool all the way back down. This will drive off any excess SO2 gas that may be causing the dark test results. If you are still getting the dark test result after heating and cooling, try a little more SMB. If you do not get a precipitate, check for PGM's. Take a small sample in a small bottle or test tube and add to it a small amount (a few crystals or more depending on the size of the sample) of potassium chloride and see if you get a yellow salt. You could test with DMG which would be faster if you have any.

 

[anachronism]

Given the base material in post 1 the likelihood of PGMs has to be extremely slight. The green colour is most likely to come from the base pin material some of which is left behind before the dissolve.

 

[Grelko]

Decant what solution you have to another beaker and rinse the powder. Add the rinse into the decanted solution. Heat the solution to steaming and see if you get any reaction or color change. After an hour or so, turn off the heat and let the solution cool all the way back down. This will drive off any excess SO2 gas that may be causing the dark test results. If you are still getting the dark test result after heating and cooling, try a little more SMB. If you do not get a precipitate, check for PGM's. Take a small sample in a small bottle or test tube and add to it a small amount (a few crystals or more depending on the size of the sample) of potassium chloride and see if you get a yellow salt. You could test with DMG which would be faster if you have any.

The only items I have to use are HCl, Cl, H2O2 and SMB. I looked for potassium chloride, but the only "salt substitute" at the store was Morton's. It has Potassium Chloride, Fumaric Acid, Tricalcium Phosphate And Monocalcium Phosphate. I'm not sure if it would work properly.

I'll be decanting and rinsing this in a few moments, then evaporating and testing. I may be done before it gets too dark, so I can take a few more pictures during or afterwards.

Given the base material in post 1 the likelihood of PGMs has to be extremely slight. The green colour is most likely to come from the base pin material some of which is left behind before the dissolve.

I didn't give the second jar enough time to dissolve the material completely, so there's still a lot of copper in it.

I don't think there would be any PGMs in it. It could be a bonus, except I don't really have any way to refine them.

I have a feeling that it's just because I didn't fully incinerate the filter and added borax while doing so by mistake. Then added way too much SMB.

The only things that should be in there are... Jar 1 had gold, copper, some nickel and a tiny bit of silver (I had the button tested before I dissolved it). Jar 2 should only be gold, copper and maybe some nickel. (The TV mylars are just gold fingers on plastic)

Both jars had rusted lids, so a little iron might be in there also.

 

[Grelko]

Well, so far so good. The orange solution is now pale yellow. Once it cooled down, it looks like silver chloride at the bottom. It's the same type of "cotton fluff" I've seen before. There's a chance that it might be tiny bits of filter also.

I did get a little dark brown powder, but it's extremely fine. It looked like mist in the rinse water until I let it settle for a while.

First of all, here is one type of the TV mylars I was talking about.



Here is the left over material that I didn't let completely dissolve in the first place . I'll be working with this next.



Original solution after decanting.



Before decanting, the original beaker had a yellow precipitate. After decanting, when I added water to it, most of it dissolved. It was mainly just salt at the bottom.



Stannous test for each solution. Decant on the right "orange", rinse on the left "yellow precipitate".

 

[Grelko]

After adding stannous.



Second rinse of the yellow precipitate.



Second rinse, stannous test.



Third rinse, nice and clear. You can see a little of the recovered dark brown powder.



Stannous stains. I gave them atleast 10-15 minutes, before rinsing them out with water. The bottom middle stain, was from the third rinse stannous test. It had almost no reaction, but after a couple minutes under the flourescent lights in the garage, before I rinsed everything out, it got slightly darker.

 

[Grelko]

This is the original decanted solution, after adding all of the rinse water. It went from 75 to 200 ml, then I evaporated it back to 100 ml. The orange is completely gone and it's a pale yellow, with what looks like cotton at the bottom. (silver chloride?) There's a little powder mixed in with it.



Stannous test after evaporating.



Stannous stain afterwards. It looked slightly purple, but more brown under the flourescent lights. (positive for gold with iron giving a false positive mixed together?)

 

[Geo]

So you are getting a dark, almost black test result after heating and letting it cool? It's not the SMB causing a false positive. Did you add any more SMB to the cooled solution to see if you get any more precipitate?

 

[Grelko]

So you are getting a dark, almost black test result after heating and letting it cool? It's not the SMB causing a false positive. Did you add any more SMB to the cooled solution to see if you get any more precipitate?

Not yet, but I will in a minute and let you know.

 

[Grelko]

I added 1-2 grams of SMB. There wasn't any fizzing. After I stirred in the SMB, the pale yellow solution looks more like a brown "mud water". I gave it about 10 minutes to settle, but that didn't do much. I was going to give it a few hours, or until later today to see if anything dropped. There may have been a little more of that cotton at the bottom. Also, a tiny bit of salt.

The "mud water", looks about the same color as the powder I got from the beaker with the yellow precipitate/salt in it, just more diluted.

Is there any chance, that something "maybe iron?" could have cemented out the gold in such small particles, that it's acting like a partial colloid? That could explain why it's taking so long to settle, if it even will.

I used a paper towel for the stannous test this time. It looks like the black might be a little lighter than before, possibly going dark brown or purple, I couldn't tell. I'll check it again once the sun is out.

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Edit - Could this be possible?

ferric oxide, plus stannous "tin chloride", equals ferric chloride? http://cdn.instructables.com/FHK/ROWL/FEQHFHZE/FHKROWLFEQHFHZE.MEDIUM.jpg

It could explain the orange color of my original solution if there was tin in there also. Concentrated looks almost black (stannous test result?).

The mason jar lids might have a thin layer of tin coating the steel and when it rusted, iron and tin both got into solution, giving it the orange color.

Except that, more iron "ferric oxide" got into the solution, so that when I tested it with stannous "tin chloride" it converted into ferric chloride and gave the black result?

But, the more diluted my solution got, the more yellow it looked, possibly converting into the pigment "yellow ferric oxide?". Because the tin would have become less concentrated in solution, so the iron [stt]and gold chloride[/stt] would show up more.

 

[Grelko]

I let the solution settle for a good 18 hours straight. It's almost completely clear, maybe a slight hint of yellow.



There is alot more of that cotton at the bottom, and a little more powder.



The stannous result is almost the same. To dilute it a little more and possibly get something besides black to show up, I tried 3 drops of solution to 1 drop of stannous.



Afterwards, I tried adding a few more drops of stannous to the result and it just gets darker.

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I was thinking about decanting the solution, evaporating it dry, adding HCl and testing with stannous.

For the precipitate (cotton and powder) I might try HCl/Cl to re-dissolve, test, dilute with cold water "incase it's silver chloride", filter, then use a little SMB to get the powder back.

The powder from the previous beaker "yellow precipitate", I was going to re-dissolve in HCl/Cl and test it also.

Edit - I made sure to buy plastic mason jar lids, so that I don't have the "rusted lid" problem in the future.