AP'ed Finger process

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

goldgee35

Active member
Joined
Aug 15, 2016
Messages
29
Location
Michigan
2 days waiting for these foils to go into the HCL 3 pt + NaHCO 1 pt... (like watching grass grow).... maybe the Au is gone already leaving the Cu, Zn, Sn etc..... theres also fluffy grey dust :roll: ......
 

Attachments

  • IMG_2267.JPG
    IMG_2267.JPG
    395.5 KB · Views: 280
  • IMG_2270.JPG
    IMG_2270.JPG
    348.2 KB · Views: 279
Sodium hypochlorite - Wikipedia
https://en.wikipedia.org/wiki/Sodium_hypochlorite
Sodium hypochlorite is a chemical compound with the formula NaOCl or NaClO, comprising a ... it a significant safety risk. In particular, mixing liquid bleach with other cleaning products, such as acids or ammonia, may produce toxic fumes.
Chemical formula‎: ‎NaOCl NFPA 704‎: ‎0 2 1OX
Solubility in water‎: ‎29.3 g/100mL (0 °C) CAS Number‎: ‎7681-52-9 (anhydrous); 7681-5...
 
Ahhh… You had said you used "HCL 3 pt + NaHCO 1 pt". I hadn't seen NaHCO before, but it wouldn't have been the first time I learned about a new process here.

Dave
 
You did not make a mistake, Dave. Goldgee35 originally wrote NaHCO, when he should have wrote NaClO or NaOCl.

Time for more coffee.
 
I used to do chlorinations in the organic chemistry field, specifically with naocl, thats sodium hypochlorite.
Ive substituted it with DCCA, TCCA as well, thats di and trichlorocyanuric acid.
Theyre chlorinating chemicals, eg poolshock for swimming pools etc. Sodium hypochlorites a bit bulky thats all. Its available 15% as pipe cleaner stabilised. The tri-shock is 92% available chlorine, the di- 66%

Trichlorocyanuric acid takes a while to go into solution

Dichlorocyanuric acid dissolves easily

If you want to keep the free chlorine in solution keep the temperature down. And use a dilute solution. It starts coming out about 13c

What ph ranges can you effect auric chloride reaction at? I suspect the ph value would drift and youd need to adjust ph periodically..

And can you preferentially chlorinate gold leaving some other base metals unnaffected using ph?

I wondered if it can be used to leach in certain situations thats all

Edit: answered my own question,
"
Controlling solution pH and Eh is important for stabilizing the gold complex. Failing to do this would cause the gold to reprecipitate, after it is dissolved from the ores (Baghalha, 2007; Soo Nam et al., 2008). The stability region of [AuCl4]¯ is determined by the Pourbaix diagram of the Au–Cl system."

Basicaly use an orp meter as it drops to 400 top it back to 1000 keep ph within certain boundary. When it stops moving reaction is over
 
This process is fairly simple and straight forward. Roughly equal amounts of hypochlorite (by weight) is needed to dissolve finely divided gold, such as foils. If you expect 10g of gold, 10g of hypochlorite should dissolve it. You added an excess of hypochlorite. Sodium hypochlorite is a base and will neutralize HCl.

The working mechanism to the process is the hypochlorite is decomposed by the HCl into sodium chloride and chlorine gas. There is the possibility of adding so much hypochlorite that you raise the PH so high that the solution can not hold any more dissolved gold salts. Also, the solution becomes saturated with sodium chloride and no more reaction can occur.

It is better to go heavy (within reason) on the HCl and light on the hypochlorite giving a resting period in between doses to let the chlorine gas do it's job. If you added both chemicals together (premixed), the chlorine gassed off before all of the gold was dissolved.

let everything settle and decant the clear solution into another beaker and warm to steaming and evaporate up to half the volume to concentrate the gold. Salt will form when it cools, this will be sodium chloride. Decant the cool solution and rinse the salt lightly with chilled water to remove any gold solution. Put fresh HCl on any remaining foils and start adding hypochlorite in small doses and give time for the reaction to occur and the chlorine to do it's job. You should have a better result.
 
Back
Top