Non-Chemical Evaporating Auric Chloride

[Rag and Bone]

Can I evaporate auric chloride (foils in HCl-Clorox) to reduce the volume?
I want to drop it all in one container. As it is, I will have to split it up into several batches to fit my beakers.

 

[eagle2]

Absolutely, the best thing to do.

You will drive off the Chlorine and evaporate most of the HCl. You don`t want to precip. your Gold from a too acid solution.

If you get a white crystalline precip. upon cooling add some water to try to dissolve it again, or filter it and wash the white precip in the filter to get all the auric back into solution.

Al

 

[Rag and Bone]

How do I know when to quit evaporating? Can I take it too far and cause problems?

 

[eagle2]

You can evaporate the solution to a small volume. Depends on the amount of HCl acid and the amount of base metals you had in the solution when starting to evaporate. You want to end up with a Ph of 1-3 if your next step is using SMB. Dilute with a small amount of water and if a white precip. starts to form let it form completely and filter this away. Anything else and you better get it back in solution, because you probably evaporated too much HCl.

Takes a little getting used to, but I find it much easier than trying to neutralize a lot of HCl with Bicarbonate.

Some refiners do use Sodium Hydroxide (lye) to neutralize but if your not skilled you can knock down some gold prematurely.

Tell me how you got blisters?? I hope your using a hot plate with a shield on the plate and pyrex beakers??

Al

 

[lazersteve]

Rag,

I have never had to evaporate my HCl-Cl solutions. You may be using too much to get the job done. My largest single run of HCl-Cl to date was dissolving 39 grams of gold powder for a second refining cycle in less than 500 mL of HCl-Cl. The color of the pregnant solution is a very deep yellow-orange color. The gold precipitates in less than 1 minute, and it comes down very light tan before washing.

Pace yourself when using HCl-Cl, give the solution time to work and only use heat if you can't get the powder or foils to dissolve with vigorous stirring. Add clorox in extremely small doses and be sure it has done it work before adding any more. Stirring while adding the clorox helps the gold come in contact with the chlorine gas as it's produced. Steve Spevak had a great suggestion to introduce the bleach at the bottom of the muriatic acid so the chlorine produced would react with the gold powder as it rises up in the solution.

Eagles suggestion about adding a little tap water to check if a white powder precipitates is valid. Always filter your solutions until they are crystal clear (total transparent with color) with no turbidity or sediments before adding SMB.

Steve

 

[Bernie Foley]

Hi Steve,
I am using taller beakers and not so big in diameter. It helps to keep splashes down and nice for settling. wouldn't a glass tube with a small funnel at the top be good..I don't have any thistle tubes(funnel). I can make a funnel tube in pyrex rather easy! Would be handy to stir with also
making additions of chlorox easy! Have a great day!....Bernie

 

[Rag and Bone]

I'm having trouble getting foils and powder to dissolve quickly. When I refine I only have a short timeframe and I need things to go quickly. Last weekend I put 30g of foils in powder in HCl-Clorox on Friday night. Sunday morning there was still intact foils and the powder was untouched. So I added more clorox and heated it up. I don't understand why a few grams will dissolve in seconds but 30g will take days.

 

[lazersteve]

Rags,

Stirring is vital to the success of the HCl-Cl process. Very low heat helps also.

Did I mention stirring is important?

Small additions of clorox and lots of stirring.

I have dissolved 30 grams of foils mixed with powder in 20 minutes.

When stirring doesn't seem to be going anywhere add a touch more clorox.

Steve

 

[Oz]

Steve,

Have you ever tried putting gold left from an inquartation after nitric and washing into this solution?

Is there some good reason not to try it? It is nice to get away from AR when possible. This has the added bonus of seeming simpler as well once you get a feel for the Clorox.

Thanks!

 

[lazersteve]

Oz,

Yes,

I've dissolved gold sponge from inquarting with HCl-Cl on many occasions.

The sponge and powder tend to require a gentle heat to get the gold into solution.

Don't forget to stir.

Stirring allows the gold to come into contact with the Cl2.

Steve