GRF Search!

How to separate silver from gold ore>

<<

was351

User avatar

Member

Posts: 2

Joined: February 21st, 2013, 5:05 pm

Post February 21st, 2013, 6:46 pm

How to separate silver from gold ore>

We have a mine and recently got some gold by hand crushing some ore we identified using a metal detector. We got 21.5 ounces of gold chunks from about 100 lbs. (2 - 5 gallon buckets) of rock. We got these gold pieces by simply picking them out of the crushed ore. We haven't processed the small stuff yet, which we will do by pulverizing and concentrating with a table or a spiral wheel. We took 8.1 ounces of the gold chunks and had them professionally melted and assayed. After melting the raw gold chunks, we ended up with a button that weighed 7.4 ounces and which assayed at 85.44% gold, 13.23% silver, and 1.33% other (probably copper). My questions are: 1) At what point in this process should we try to separate the silver from the gold chunks; 2) Could we use aqua regia to first precipitate the silver and then use SMB to drop the gold; 3) should we just let the professionals do it?

was351
<<

butcher

Active Member

Posts: 7174

Joined: January 6th, 2008, 2:09 pm

Location: Pacific NW

Post February 22nd, 2013, 9:58 pm

Re: How to separate silver from gold ore>

was351,

Depending on gold to silver ratio content of the metal, the silver in aqua regia can make it hard to dissolve the gold as the silver chloride forms a crust keeping the acids from dissolving the gold, and then also the gold can make it hard for nitric acid to get at the silver to remove the silver copper from the gold.

In your gold the silver ratio is pretty low so you may be able to get by without in-quartering your gold with silver in a melt and parting it with nitric acid, before moving to refining the gold in aqua regia.

If you decide to try and recover your gold from the silver and copper and then refine it, you should begin with reading Hokes book, she explains the process.
<<

was351

User avatar

Member

Posts: 2

Joined: February 21st, 2013, 5:05 pm

Post February 23rd, 2013, 1:11 am

Re: How to separate silver from gold ore>

Thanks butcher for the response. I had started reading Hoke and came upon the part that said if the silver content was higher than 8% that inquarting would be required. Our assay showed 13+%. I haven't read it all yet but I am working on it. We'd really like to process it ourselves because it looks like it would be interesting and a lot of fun. Getting this much gold from an afternoon's work is really exciting. We can't wait to get back into the mine to really start working it with the proper equipment and a plan on what to do with the gold once we get it out.

was351
<<

nickvc

Active Member

Posts: 2576

Joined: September 14th, 2009, 9:53 am

Location: birmingham

Post February 23rd, 2013, 4:57 am

Re: How to separate silver from gold ore>

If your material was cornflaked or very thin you might get away with direct dissolution in AR but I think in honesty I'd go for inquatation to ensure you can refine your gold in one process cycle. It would be better to use silver as it will act as a collector if you have any PGMs present and will use less nitric but copper can be substituted to start and silver used as you collect it from your material, simply cement it out of the nitric with copper,rinse dry and use it for inquartation.
Make sure you are aware of the dangers involved in refining, not just melting but the acids, fumes and noxious by products, waste the whole process produces and be sure your fully equipped to process before you start. It sounds as if you have found an excellent source and I wish you luck in your endeavours.
When you have run your inquartation 4 or 5 times with the same silver I'd be tempted to have an assay done to check if you have any PGMs present, they might not be but if they are it's an added bonus.
<<

butcher

Active Member

Posts: 7174

Joined: January 6th, 2008, 2:09 pm

Location: Pacific NW

Post February 23rd, 2013, 7:33 pm

Re: How to separate silver from gold ore>

Keep reading Hokes, good winter time project till the mining season rolls around.

Page 66 C.M. Hokes states up 8% silver dissolving gold directly in aqua regia is not much of a problem.
under 12% silver can be done with some difficulty.
greater than 12% silver it is best to in-quarter the gold, as the silver chloride becomes so difficult.

much also depends on conditions.

your 13% would be difficult, in-quartering, or upgrading the gold content would be the best choice, in-quartering the gold with silver is the easiest.

Depending on the condition of the mined gold (small flakes) you may be able to remove some silver with nitric, before trying aqua regia, or take previously recovered gold that has had silver removed to upgrade your gold.

Once you understand Hokes, and begin using what she teaches, you will find what works best for you and the material you are working with.

Personally I just in-quarter the placer gold, it is not that much problem for me and the little bit I am able to mine, this way I also upgrade the sterling I collect at the same time and do not worry about fighting the silver chloride.
<<

nickvc

Active Member

Posts: 2576

Joined: September 14th, 2009, 9:53 am

Location: birmingham

Post February 24th, 2013, 5:01 am

Re: How to separate silver from gold ore>

Silver chloride :evil:
Only slightly better than tin in AR in my opinion and I have produced masses of silver chloride over the years, sometimes it's inevitable by the processes we need to use but given a choice I'd always use nitric to dissolve the silver and then cement it out with copper and keep the chloride to a bear minimum, especially as it has a nasty habit of containing some of the gold i was after.

Return to Prospecting, Mining, Ore Concentrates & Geochemical

Who is online

Users browsing this forum: No registered users and 3 guests

[Most Recent Quotes from www.kitco.com]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by Vjacheslav Trushkin for Free Forums/DivisionCore.