Brandon/kelly said:
Hello all my name is brandon kelly is my soon to be wife so I mix our names as my user name. I have been reading hoke, and any other litature I can get my hands on. I've been reading all over the forum here, but havent seen a problem like I have here so thought Id finally ask someone.
WELCOME to the forum. And Congratulations.
A few good buddys of mine was telling me how they use a precipitant called storm to drop there gold, and they got a better yield than using metabisulphite. So i thought I'd give it a try I started out with 6 ounces 23 - 24 karat pins, and connectors in a auqa regia bath.
Your Storm Precipitant, I believe, and could be wrong, is Sodium bisulfite, Sodium hydrogen sulphite.
After it got hot at low boil It put off a bad amonia type smell. is that normal?
You should not boil your solution, not ever. You also shouldn't be dissolving anything indoors without a fume hood, and even then it should be totally separate from your house. You do not want to breath in the gases that this process creates. AR, as it dissolves metals, produces NOx gas, a brown rusty red looking gas that can kill you if you breath it in. This is extremely important, you might also be affecting people around you. You should only dissolve things in AR either under a fume hood, or outside in a well ventilated area, upwind from the reaction.
1st pic is what batch looked like in the flask at bottom theres like a tan type mud looking stuff then on top of it theres like a mushy crystal looking stuff then the remaining liquid is still a emarald greenish looking more darker than when 1st started.
The tan type mud on the bottom is probably your Au (gold). It should be heavier than whatever other solids you have in your solution, and thus it should sink to the bottom. There are a few questions I have however about the other things, and what they might be. First, the green crystals/sludge should be Cu (copper). Your solution does not have enough liquid to take all the copper into solution, so it starts making crystals as soon as your solution cools down.
Did you soak your pins in HCl to dissolve any Sn (Tin)? If you did not, the tin probably dissolved and created metastannic acid, that would explain the white material. If the solder had silver in it, which a lot of electronic solder does, you might also have Ag (silver).
The reason your solution changes colors is because AR attacked whatever was on the outside of the gold plate (solder?) then the gold plate which would make your solution yellowish, but at the same time you are dissolving copper underneath which would start turning your solution a light emerald green, until everything is dissolved then your solution would, since you don't have enough solution, turn dark green in color. That is normal and nothing to worry about.
2nd pic is a close up of what it looks like
I think the green crystal like material sludge in your solution is copper, and if you add more water, I believe it should readily dissolve without issue.
3rd pic is a even closer shot
How much precipitant did you use? The white material might be the Sn (tin) I mentioned above, but it also might be too much precipitant.
4th pic is a shot looking down into the flask you can see the blueish greenish crystal mush stuff
Add water, hopefully this dissolves the sludge/crystal Cu (copper)
5th is pic of some the crystal mush I pulled out on a measuring spoon.
If you could provide better pictures, someone might be able to identify what you have in your filtering flask. I am taking a stab at it, and assuming what I see in your pictures are certain things that might be associated with gold plated pins, but I could be wrong about any of it. Please keep this in mind.
The white material might be tin, or it could be tin/silver solder if you didn't use HCl before dissolving them in AP.
And i apolagize to anyone If this post and pics are in wrong spot if they are will someone please move, and advise me!
Posting pictures is more than acceptable, it's encouraged, no worries on that count.
This whole batch has me bum fuzzled I've never seen a AR do this, but it's first time I've ever used storm precipitant.
You might have several things going on, can you give us more information about your pre-process? Did you soak in HCl? Did you prepare your pins in any other way?
Is all this normal using storm? i sure hope someone can tell me that my gold is still saveable ill never use this stuff again. I followed directions on the bag, and even my buddies said use 1 1/2 tablespoons for every ounce disolved metal.
You will find people here on the forum do not generally have any appreciation for the iShor system. You can try to ask them for help, but you would be hard pressed to get a viable answer back. I think maybe you put too much precipitant into your solution. You don't put 1 1/2 tablespoons for every ounce you put into solution, you match the amount of precipitant with the EXPECTED gold yield. If you are not sure what that is, then you should make small additions and observe the reaction until you see that you are having no more reaction, then test with Stannous Chloride to insure you dropped all the Au (gold).
Any help is greatly appreciated the utmost.
You should make a batch of Stannous Chloride, so that you are able to test for gold content.
Also, you might want to make a standard solution of gold so that you can test Stannous Chloride against it, and the results from your solution.
Did you incinerate your material before digesting in AR? This will burn off any organic materials or oils, etc. This is an important step with material that is dirty. If you were dissolving your material in AR, and there is any solder or other base metals suspected of being present, you should soak your material in HCl, and maybe after a thorough washing, soak in HNO3. By cleaning your material before AR digestion, you will save yourself a lot of hassle later in your process.
Remember, don't toss any solution or material, all could potentially contain values. So long as you don't toss anything, you can recover it. Your Au (gold) isn't lost, it's just misplaced.
You also might want to think about using AP or a sulfuric stripping cell to recover the Au from your pins, with Sulfuric Cell probably being the best. Barring that, if you don't have the ability to use either of these methods. You should, after your material is clean, do a Nitric Acid soak. This will dissolve the copper, and leave you with only the gold foils with maybe a little copper. The more copper you rid your pins of in this way, the less AR you will have to use for the gold foils produced by dissolve the copper. Then you filter off the gold foils and digest in AR.
I hope what I posted helps, if someone reading this finds fault in my post, please feel free to correct me.
Scott
