cool green colors! but they lead to a bit of frustration

[Exibar]

ok, I'm starting some small tests before I dig in. I have about 5 Kilos of fingers to process and I don't want to mess up I have Steve's DVD and read the foums here and try to do my homework, but ther eis NOTHING like hands on to teach you what you don't know....

I've attached a picture, the Left is of AP (Muratic and Clorox) and the right is of HCL+Clorox. I wasn't expecting the bright green for the HCL+CL... what turned it that green? Would just the copper make it that bright of a green?

The left one seems correct, I added a finger to it and it turned a nice golden color... Telling me there's GOLD in that there solution!

Now the tricky thing... I made some Stannous, or thought I did... 2ounces of HCL and about a gram of tin powder. I let it sit overnight until it was all dissolved. For the life of me I cannot get anything to show purple! I scraped fingers bringing the powder into solution, I tried the jar on the left that I KNOW has gold in solution but not a tint of Purple...
so di dI make my stannous incorrectly? Too much HCL? not enough tin? I used a baby food jar as a container for the HCL, and put the gram of tin into that... I have a feeling I'm using too much HCL and not enough tin, but I dont' have much tin powder left....
Perhaps there wasn't enough gold in solution for the left side jar? I thought that stannous would turn purple at the slighted smallest ppm in solution? I'm prolly wrong there though :-(

any words of wisdom from anyone would be greatly appreciated!

thanks!
Mike B

 

[butcher]

I have no words of wisdom just some Idea's

I understand HCl acid /peroxide as being called AP,
from your picture both solutions seem to have copper, the one on left seems to me to have the bleach and possibly gold in solution,

did you heat your stannous to get solution saturated with tin, and lil extra tin in solution if you keep it for more than a test or two,

when testing if solution has too much oxidizer (bleach) it can redisolve the gold from your test that you are trying to precipitate out (purple of casius), with stannous chloride solution, try heating your test sample to drive off extra oxidizer and chlorine, see if that helps, when testing your stannous chloride with your known gold solution.

 

[eeTHr]

Mike;

Stannous chloride works by actually precipitating Au, but it only precipitates it in very small, colloidal particles, of a size which give a purple color (there are other chemicals which will produce other sizes of colloidal Au, which are other colors, too, but I don't think they are used in refining gold).

If your Au solution has not spent it's ability to dissolve more Au, then it can dissolve the colloidal gold as soon as it is produced by the stannous chloride, resulting in no color change.

People who use the acid/clorox method have said that they like it because they don't need to evaporate any nitric, like you would with aqua regia. While others using the A/C have said that they warm it to get rid of the clorox, or let it set overnight and it will evaporate out on it's own.

I haven't seen anything mentioned about the acid/peroxide needing any evaporation, but since you only used one fingers strip, that is such a small amount of gold that the solution may still be "hot" enough to dissolve any colloidal Au produced by the stannous.

Also, when testing solutions containing small samples of Au, I have found that using a spot plate or white plastic spoon tends to show color more readily than on a piece of paper. Put a drop of the solution to be tested in the spoon, then a drop of the stannous (it's best to use a different dropper for each solution, or you will end up with a purple dropper, and precipitate some of the next solution you test into colloidal-sized particles which tend to pass through coffee filters).

There should be some un-dissolved tin in stannous chloride testing solutions, as the solution will weaken after a week or so, but it will last longer with the extra tin in there to replenish it. Others on this forum report making their stannous with HCl only, but I think they are referring to what is called commercially "muriatic acid" which is HCl at about 31%.

Oops! I see butcher has already answered your question, but since I typed this all up, I'm posting it anyway! :lol:

Don

 

[butcher]

I'm glad you posted Don, you explain that much better than I could, thanks.

 

[Exibar]

thank you both for the replies.

Yes the one on the right is the AP solution and the one on the left is HCL+bleach.

Nope, I didn't heat my HCL to make the stannous. I also didn't realize that it went bad so quickly, I only have about a gram of tin powder left.... I've heard that electronic solder will work 60/40 (tin/lead), is that correct? Can I use that with good results if I heat the HCL? or should I go ahead and buy a pound of tin powder from that guy on ebay that has it for $26 per pound?

So, let me see.... I does sound like the HCL+bleach was still hot. As there was only a small amount of gold from the finger in there. Understood.
If I let that sit overnight, the bleach will evaporate and I'll be able to test it? How about if I dip a Q-tip into the solution and let it sit out overnight, will I be able to test successfully tomorrow and get purple?

sounds like I have two issues: 1) not enough tin in the stannous as I didn't heat it to saturate (or super-saturate so it will last longer) the solution. and 2) I still had way too much bleach left in the solution I was testing. I should let it sit overnight, or heat it up to let the bleach evaporate before testing.

thanks again guys! I dont' want to dig into a larger scale until I get this small scale down pat. I'm gunna try again this week. I saw many gold foils floating in the AP, so I think I'm good on that front. Um, I think! ;-)

Mike B

 

[Anonymous]

You want lead free solder 95 tin 5 anthimony. I put 3 ml of hcl in test tube and a 1 inch strip of solder, heat, let it go until it stops, usually a little bit of solder left after the reaction is done, works for me.

Jim

 

[eeTHr]

Where to find the solder---

http://goldrefiningforum.com/phpBB3...4988&p=42832&hilit=tin+solder+stannous#p42832

Dipping the Q-Tip and letting it sit overnight sounds like a pretty good idea.

If that doesn't work, then since you may have quite a bit of clorox left in the solution, it would probably be better to warm it. It will stink of chlorine, though. I hope you can heat it outside of your home. If not, letting it stand in the sun all day would be better for your health than doing it in your living space.

Since the stannous test is very sensitive, your solution might work as-is. If it's a little old, you can revive it by adding more tin.

One way or another, you are going to be seeing a purple test result! :lol:

Don

 

[stihl88]

Well you mention (Muratic and Clorox) and the right is of HCL+Clorox

Last time i checked they were the same thing?

 

[Exibar]

Well you mention (Muratic and Clorox) and the right is of HCL+Clorox

Last time i checked they were the same thing?

OOPS, yah, that should read (Muratic and Peroxide) instead.... I tried to edit but the board won't let me for some reason :-(

sorry for that typo :-(