Second refining of gold powder

[chsivert]

Hi, i'm new here and this is my first post. I want to thank you all for the great info regarding gold recovery and refining, it has been very helpfull and a special thanks to all the talented people here, i've learned a lot!
I started refining as a hobby and still is. I have read Hooks book and over and over and togheter with the info from you on this forum i feel i have got a basic understanding of the art of recovery/refining, but i dont compromise my health or others doing this.
I've gathered a lot of scrap during the years and have refined and recovered approx. 200 grams of "gold powder" during a three year period.
I want to refine this a second time and my goal is to get it as pure as possible with my equipment at hand.

I live in Norway (maybe the only one on this forum) and Nitric acid is almost impossible to get, because of the "terror hysteria". Before when it was avaiable it cost about $300 for one liter:S
I can barely get my hand of Potassium nitrate and have used this to recover and refine in coherence with poor mans Aqua Regia.

Anyway the powder i have recovered has been washed with water(3x) and HCL(3x). I've bought some ammonia (9%) household cleaner to remove any silver present, but i havent done this yet. After this i want to refine it one more time, but i just have the HCL/Clorox option available and think this can be difficult with 200 grams. Do you have any advise before i attempt this further?

Should i use only Aqua regia to refine it and avoid HCL/Clorox because of this amount? I can buy Potassium Nitrate, but the price is around $250 for a pound on the pharmacy, the price is sick,
clorox is cheap! Any advise please

Also was thinking of making some "home made nuggets" and sell them on Ebay, but it looks shipping them to the USA and to other countries is impossible because of the regulations. Shipping precious metal to the US is prohibited by mail:S I guess im stuck with the gold, buyers in norway dont want to pay more than approx 80-85% of the spot price.

Regards
Christian

 

[necromancer]

do you have a fume hood & scrubber ??
----------------------------------------------------
if so you may want to look into this process

https://www.youtube.com/watch?v=Iwvt_QHeb7o

trichloroisocyanuric acid, dripped into hydrochloric acid inside a gas generating apparatus

http://www.ebay.ca/sch/i.html?_sacat=0&_from=R40&_nkw=Separatory+Funnel&_sop=15


EDIT: added ebay link

 

[joubjonn]

Look up Harold's wash technique and I think you should be fine. You shouldn't have a problem cleaning it up without having to drop it again. I think the point of the second drop is for getting .999 or better. I find just the ammonia wash alone really cleans the powder up nicely. Then again I don't know how your first drop went. Explain that and maybe some others with some more experience then I have can tell you more. I can imagine how hard it would be to get nitric in Norway. It's very easy in the states. Shoot I just bought my second 2.5l bottle yesterday. $42 with tax. No problem.

 

[joubjonn]

Norwegian government is also a stickler for health and safety even offshore. One of my coworkers had to get special permission from the Norwegian equivalent of our surgeon general to go to an offshore platform because he has a insulin pump. It was a one time deal. I don't think he can do it again.

 

[nickvc]

Welcome to the forum and congratulations on reading before posting.
I think you will be able to refine your powder easily with the hcl chlorox process, it has limitations but works well with powder and foils.
If you wish to sell your material then try either Germany or the UK where I'm sure 95% + will be offered and shipping will be easier and cheaper or simply take a long weekend break and trade it while on holiday 8)

 

[chsivert]

Thanks for the reply!
I dont have any scrubber so i do this outside. On my previous recovery with HCL/Cl i have used a syringe and added clorox in small amounts to avoid foaming, it gives me a better control than pouring it. My drops have been mostly brown, both dark and light, but sometimes grey and dark. When grey i have refine it a second time to get it brown (small drops, 1-10 grams), before i mix it with my other powder.
Overall my powder has now a light brown color, but not sure how pure this is?

Chris

 

[Lou]

Can you get good, high quality sulfuric acid?

Pulp it in that with a ultrasound and the gold should be very fine.

 

[freechemist]

In place of chlorox you can use sodium chlorate, NaClO₃, as a rather concentrated aqueous solution, which is added slowly to the constantly stirred reaction-mixture.

Equally well as an oxidant works 35% hydrogen peroxide, H₂O₂, whereby HCl used has to be rather concentrated (ca.20%, ev. more).

Addition of bromide to the reaction mixture in form of 48% HBr (e.g. 10% of the HCl-volume) or a few grams of sodium bromide before addition of the oxidant, accelerates the dissolution of gold.

Applying heat and use of a reaction-apparatus equipped with a reflux-condenser is recommended.