Aloha, fun & authoritative answers -- no cost, no registration, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Where the
world gathers for metal finishing
Q&As since 1989

-----

Refining of scrap gold

Q. I have 4 pounds of scrap gold. I want to learn how to refine it. Any suggestions? Will appreciate your reply.

Santiago Maldonado
Maldos - Agua Prieta Sonora, Mexico
2002

2002

1. Make up solution => HCl:HNO3 = 3:1
2. Make gold to small pieces (about 0.5cm)
3. Put small gold pieces into the solution.
4. Boiling (until dissolve out)
5. Boiling continuously...(For NOx out)
6. Add HCl 2~3 times ( HNO3 will disappear and the solution will be almost HCl).
7. Add Urea for elimination of the remaining small amount of NOx. Bubbles will be generated (until no bubbles).
8. Cooling the reactor until 80-90 °C. then Add Sodium sulphite---> you can see the yellow gold powder.
9. Filtering with warm pure water until pH.
10. Burning them including filter paper at 1000 °C.
11. Melting them with O2 torch. You can get 99.9% up pure gold.

Gyu-Sik KIM
- KOREA(south)

Q. Hi,

I am in search of a gold refining procedure other than using nitric acid and muriatic acid [affil links]. Does anyone know of such a procedure? Also a vendor offers a simple gold refining machinery which uses this principle. It uses a certain type of salt water bath using electric current. Does any one knows which type of salt they are using. Please give whatever help you can. Thank you very much.

Regards,

Mithun Rao
- Mumbai, India
2002

A. GC Salt is one name I came across.

Tom Eames
- San Jose, California, USA
2005

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: