newbie messed up I think

[jake11]

I just got done releasing my foils from finger using the Hcl/peroxide method. That went well , dissolved my foils using the Hcl/chlorine method. I got a very nice deep gold colored solution. When I went to drop my gold I think I messed up using bondie stump out. My solution turned clear and emitted a noxous gas. All of the methods I learned from lazersteve , with the exeption of the bondie stump remover to do the drop with.
I have sent an e-mail to steve explain what I did and what happened , I'm also going to ask everyone else as to what they think. My biggest quetion here , can I salage my gold ?

 

[martyn111]

If keep all solutions and solids your gold is still salvagable.
If you could supply more details,
how long from dissolving the foils until you tried to precipitate your gold?
Is your stump out definately Sodium metabisulphite?

If you try to precipitate too soon after dissolving your foils you will likely still have excess chlorine in solution, your gold will be precipitating but re dissolving. You should allow excess chlorine to dissipate before trying to drop your gold, either heat the solution, DO NOT BOIL, then allow to cool, or allow the solution to stand overnight before proceeding to filtering and precipitating.
Remember to precipitate from a cold solution as the reaction is exothermic (self heating).

 

[jake11]

I waited over 24 hours before trying to dropped the gold. If I'm reading the Msds correctly bondie brand stump out to be sodium pyrosulfite.

 

[jimdoc]

I waited over 24 hours before trying to dropped the gold. If I'm reading the Msds correctly bondie brand stump out to be sodium pyrosulfite.

There are two different types as far as I know. You may have the wrong type.
You should check for a wine making or brewery supply house for SMB.

Jim

 

[martyn111]

According to wiki sodium pyrosulphite is the same as sodium metabisulphite

http://en.wikipedia.org/wiki/Sodium_metabisulfite

What weight of foils and how much solution are involved in your process?
By wafting your hand across the top of your solution (rather than taking an UNHEALTHY sniff) can you smell chlorine?

 

[jake11]

I dissolved about 4 grams, no wafting necessary it was obvious that chlorine was present. Too much chlorine?

 

[jake11]

Used about 1/2 cup of Hcl and approximatley 1/4 chlorine bleach.

 

[martyn111]

I dissolved about 4 grams, no whafting nessicary it was obvious that chlorine was present. Too much chlorine?

I would try heating the solution to drive off the excess chlorine, keep it warm for about 15 mins, then allow to cool before trying again to precipitate. Update us with the results good or bad.

edit spelling

 

[jake11]

Ok I'll try that. At this point I'm going to let the solution go until Friday.

 

[jake11]

After setting for a while it appears that my has started to drop. My solution is now brown except for the top 1/2 or so.

 

[nickvc]

As a general rule I would always add the amount of hydrochloric acid required first, a little excess won't hurt, then slowly add increments of your oxidiser whether bleach or nitric slowly only adding more once all reaction ceases until all your values dissolve, if after adding a small amount of oxidiser there's no reaction and values are still present add a little more hydrochloric and the reaction should restart, using your chemicals this way should negate the problems of removing excess oxidiser before precipitation.

 

[tek4g63]

I completely agree with Nick.

The way I digest my foils is like this:
-clean the foils well and place them in the reaction chamber.
-I add enough water to half cover the foils.
-Then pour in hydrochloric acid to finish covering the foils, or a bit more. ( I use 31.8% HCL )
-Stir well, and while stirring add just a few drops of bleach
-Keep stirring and after all reactions have stopped add another few drops of bleach. Keep doing this till all foils have dissolved. ( remember to allow several minutes between additions of bleach to prevent excess chlorine build up )
-Allow the solution to sit uncovered over night ( at least 8 hours ) just to be sure that all chlorine has been eliminated )
-Filter, add about a third its volume in chilled water to the solution, then precipitate with desired precipitant

You will be surprised at how little bleach you actually need to dissolve your foils..

This is how I have done it every time and I have not yet had any problems (except the one time when the water I used to dilute was not chilled, actually hot from being out side ).

I hope this can help you on your next batch.

Don't forget to post a picture of your button.
Thad

 

[jake11]

Well here it is. Not sure why it looks the way It does ,but, some more reading will help me figure it out. Thanks for the help everyone.

 

[maynman1751]

It appears to me from the pic that your gold isn't very pure. It may still have some impurities. You could digest with nitric and re-refine to get a better quality. It's up to you!
Did you use proper washing procedures to clean your foils before dissolving? Did you use proper washing procedures on your dropped powder? Did you refine twice? These are the questions you need to answer.
Also, I wouldn't discard the solution that you dropped from until you test with stannous to make sure your solution is barren of gold!

 

[Harold_V]

. Not sure why it looks the way It does ,but, some more reading will help me figure it out.

It's not pure. It may be close, but if it was, the surface would be shiny, with no hint of pattern. It would also have a much better color, and a pipe, which yours distinctly lacks. The dullness and lack of luster betray the lack of purity in gold, and does so readily. It's a very reliable method of determining if the end result is good, or not. You might also examine your melting dish, which should have not been used for anything aside from melting refined gold. If it has any color to the flux covering, the color can help you understand what has contaminated your gold. Also, while it's molten, if it has a film that moves from the center of the button to the edges, on a constant basis, that's the oxides being created, then absorbed by the flux. Molten gold that is pure does not create that film. It remains bright, and transmits a luminescent greenish glow.

Harold

 

[goldpete]

I completely agree with Nick.

The way I digest my foils is like this:
-clean the foils well and place them in the reaction chamber.
-I add enough water to half cover the foils.
-Then pour in hydrochloric acid to finish covering the foils, or a bit more. ( I use 31.8% HCL )
-Stir well, and while stirring add just a few drops of bleach
-Keep stirring and after all reactions have stopped add another few drops of bleach. Keep doing this till all foils have dissolved. ( remember to allow several minutes between additions of bleach to prevent excess chlorine build up )
-Allow the solution to sit uncovered over night ( at least 8 hours ) just to be sure that all chlorine has been eliminated )
-Filter, add about a third its volume in chilled water to the solution, then precipitate with desired precipitant

You will be surprised at how little bleach you actually need to dissolve your foils..

This is how I have done it every time and I have not yet had any problems (except the one time when the water I used to dilute was not chilled, actually hot from being out side ).

I hope this can help you on your next batch.

Don't forget to post a picture of your button.
Thad

please forgive me asking this as i am new at this . but why in your step by step process do you not evaporate ?

 

[Geo]

please forgive me asking this as i am new at this . but why in your step by step process do you not evaporate ?

when you dissolve using the hcl/Cl method, theres no need to evaporate to rid the solution of free nitric because there isnt any nitric to begin with. this process isnt covered in Hoke's book because it was used as a work around as many people have a hard time finding nitric acid. hcl/Cl works best on gold foils and gold powder.