recovery from G.F. Minor glitch

Advertise with us
Shop deals on ebay
xelexo
shop deals on amazon
Gold Refining Forum

Help Support Gold Refining Forum:

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

torscot

Well-known member
Joined
Sep 20, 2012
Messages
66
I normally work with silver. This is my first test run recovering gold from Gold filled items. I have quite a bit of it stashed away. So, I am learning a whole new set of rules here.

Following a method posted on here by Harold. I took 100 grams of gold filled items cut up very fine, incinerated, then placed in 50 /50 nitric and water to dissolve the base metals out. So far so good. My bottle labeled distilled water must not have been distilled water. I guess you can't believe everything you read on a label. One piece must have been gold over silver. My solution is very polluted with silver chloride. I do not want to filter and incinerate this for the next step with silver chloride in it. Silver chloride has plagued me before. That will be a mess.

I need a second opinion on my solution for this problem. I have done this in silver recovery to remove the last unconverted silver chloride after I convert to silver metal. Rinse, rinse, rinse, neutral Ph. Add ammonium hydroxide, this should take the silver chloride out of my solution, my gold foils and gold mud should remain when I filter the ammonia / silver complex out.

This treatment to remove the silver chloride should not affect the gold / gold mud? I see no reason for it to, but I desire a second opinion. 3-4 grams of gold is a lot more to lose than 3-4 grams of silver. Opinions please.
 
To be honest I wouldn't be too worried. If it is silver chloride just carry on your process and dissolve your gold leaving the silver chloride behind on the filter.
 
Two good questions. Here's the answers.

One piece that I dissolved was unquestionably gold over silver. It didn't bother me as I knew I could recover the silver later. The piece was dissolved so I know I have approx 7-10 grams of silver in my solution as silver nitrate. I had a beautiful blue solution with little flakes of gold floating around it. Perfection. The new bottle of "distilled" water that I opened and used at the end of the process was not distilled water. (mineral water?) My solution immediately clouded and dropped a white precipitate. Classic reaction of silver nitrate with sodium chloride. Anyone want a bottle of mineral water labelled as distilled. Oops some one goofed on the labeling line at that bottled water plant. That's how you get silver chloride where you don't want it.

This morning was quite sunny, so I took a little of the precipitate and put it in the sun. it was grey in 10 minutes.. Silver chloride.

The formula for G.F as posted by Harold states now to filter the solids out of the solution. Dry the solids,then incinerate, then boil twice in HCI to remove any tin. He was quite emphatic not to skip this step. When working with silver, any time I have ended up with silver chloride in my furnace, I have had a god awful mess to deal with. Along with a loss of a lot of silver values.

I am sure there is tin in there, The above paragraph tells how to deal with it. At this time though I have to deal with the silver chloride. So my original question still stands. It can be removed with ammonium hydroxide. But, without damaging my gold values?
 
torscot,

I do not know if I can be helpful here.

What I would look at are options, and the state of what I had to help me decide on what option, or method I would choose to deal with my problem.

How hard is it to filter the solution? This can give you a clue as if tin will create much problems, and help in making a decision of how to proceed.

If there was no tin, or if tin was not too much of a problem, I would dissolve the gold from the silver chloride powders.

I would not want to put the gold into solution with tin (if tin was still a problem).


If I was going to incinerate the powders, I would first neutralize them with NaOH solution converting chlorides to salt water, so that the NaCl formed can be washed away with several water washings, and leaving the silver as an oxide, both silver and gold can be volatile at around 800 degrees with chlorides involved, and at incineration temperatures, and my values, I do not want chlorides involved in that procedure if possible.

Then as you stated you have the option to dissolve the silver chloride with ammonia solution to form an silver ammine compound that can be precipitated back out of solution with acid as soon as possible.

You probably already know this if you deal with silver, but when I post I know others will read it so my response is also for them.

Silver chloride dissolved in ammonia solution should not be left unattended or left to sit in solution for long periods of time, silver chloride should be precipitated back out of solution as soon as possible from solution by acidifying the solution with HCl or nitric acid, left standing even 24 hours it can form explosive compounds (even in solution) if dry these compound are very dangerous.

Also something to consider when using ammonia solutions (or other alkali solutions like NaOH), many metals are amphoteric (including gold and silver), amphoteric metals can precipitate in an alkali solution, but can be dissolved in an excess of the alkali solution...

Gold solutions can also form explosive compounds with ammonium compounds, with this in mind be very careful when using ammonia around silver and gold solutions...
 
torscot

First - as Hokes would say - "the silver - if worth while" --- meaning is it enough silver worth chasing - if the answer is yes then 1 of the 4 following procedures

(1) The fastest & easiest - hot ammonia treatment - just be sure to drop the silver back out (as silver chloride) with HCL right away (read butchers post)

(2) use sugar/lye method to convert Ag/CL to Ag oxide - then leach Ag oxide with nitric --- lots of washing & filtering involve

(3) in a furnace using soda ash as your flux (which will convert Ag/CL back to Ag) melt & pour shot (this will be an alloy of gold silver & any other base metals in the mix) dissolve shot in AR - Ag will remain behind as Ag/CL in your AR & recovered in filtering

(4) in a furnace using soda ash as your flux (as above) melt with enough silver (at least 90% silver) & pour anode bar - run anode bar in silver cell - recover gold from anode slime

Kurt
 
Thank you Gentlemen,

I am familiar with the methods you have suggested, This was just my small test run for this process. Thank god for test runs! So your replies will get printed and put into my library. It will be a couple weeks til I get back at this project. I'll post the results.

Thank you again,
Rob.
 
Gave this a little more thought - I don't think you have enough Ag/CL to worry about - "at this point" - & anything you try to do to get the Ag/CL out of the foils is going to take more time & effort then the silver is worth & you wont get it all anyway -at this point - so what I would do

Filter foils to wash out acid - Ag/CL will remain with foils - dry & incinerate foils & do the hot HCL washes to get rid of base metals (tin, nickel, etc) Ag/CL will remain with foils - dissolve foils with AR - filter Ag/CL from AR - add Ag/CL to Ag/CL stock pot - drop gold from AR (your chosen method)

Kurt
 
Kurt,
You're right, I don't have enough silver to worry to about. I have Ammonia in stock for doing silver conversion. So I don't have to spend $15 to recover $5. i can spare an ounce or two to get rid of this silver chloride. That puts me back on the straight and narrow following this formula for GF items. That way if I have any more problems I can't blame it on the silver chloride from this step. The silver I'll just convert it back to chloride from the the ammonia and put it into my bottle (stock pot) of chloride to convert someday in the future. Thanks for the good advice.

Have you had success using soda ash as a flux directly with silver chloride in your furnace? I only tried it once, and lost so much "up in smoke" I condemned it as useless. Is there a trick to that, Something I have missed?

Rob.
 

Latest posts

Back
Top