Cell Questions

Hi Steve and all, I am new to the forum- this is my first post, but I have been gold prospecting, sniping and panning here in the Uk for over ten years.

Firstly I must say thanks for the excellent site, and steves tutorial vids are just super, Keep up the good work.

I have spent many hours reading the posts and learning lots from members postings.

--------------

I am a proffesional geologist, and have decided to do a little gold-refining on the side, starting with the construction of a cell for reverse plating, as I have a quantity of scrap plated stuff to strip.

I also have stock of many of the chemicals and acids as they are of geological use.

I have sucessfully constructed a cell, and so far I have stripped about 1kg of plated material, jewelery cpu lids etc.

So a few questions.

1. How do I decide when the cell is 'full' - I am using concentrated sulphuric (4 cups as opposed to 3 in the video as my glass cell is slighlty larger than the one shown) + glycerine (even though I have read the glycerine is not esential)

After use, the mixture will settle out over a couple of days and I can see black sludge on the bottom when it does so, there is about 1 cm of it so far over the base of the glass dish which measures 19X24 cm. There is also some black scum on the surface and around the edges.

2. Do I need distilled water for rinsing my sludge or will tap water suffice ? I am using distilled for storing my lead cathode as instructed.

3. How can I retrieve my Sulphuric once my dilution process is complete, do you have a tutorial on it ?

4. Any ideas on a melting torch as i dont currently have access to oxy/acet- maybe something for the future. Are portable propane/oxy any good, I have seen a Rothenburger kit on ebay for about £50, any use and are there other cheaper alternatives to Oxy/acet ?

Thanks , hope i can returning the favours but making some input to the forum at some point,

Best wishes,

Richard.

Hello and welcome to the forum,

limestonecowboy said:

1. How do I decide when the cell is 'full' - I am using concentrated sulphuric (4 cups as opposed to 3 in the video as my glass cell is slighlty larger than the one shown) + glycerine (even though I have read the glycerine is not esential)

Click to expand...

I typically go by the hours of operation of the cell. After 12-24 hours of operation (stripping time) with mid to high quality scrap.

limestonecowboy said:

After use, the mixture will settle out over a couple of days and I can see black sludge on the bottom when it does so, there is about 1 cm of it so far over the base of the glass dish which measures 19X24 cm. There is also some black scum on the surface and around the edges.

Click to expand...

Sink the floating stuff by gentle stirring with a glass rod. Let settle and pour off the bulk of the concentrated acid for the next run. If properly settled the amount of gold powder poured off will be small and you will get it in the next run.

limestonecowboy said:

2. Do I need distilled water for rinsing my sludge or will tap water suffice ? I am using distilled for storing my lead cathode as instructed.

Click to expand...

Tap water is fine when rinsing the cell. Proper rinsing requires 8-10 flushes of clean water. Be sure to stir the powder vigorously then let it settle between rinses. Now days I usually pour the acid with the gold in it into a tall beaker for the rinsing cycle.



The final rinse should be clear without any blue or green tint. Siphoning off the rinses helps avoid any minor powder losses due to the removal of the dirty rinse solution. Combined the first three rinses for the recovery process listed below.

limestonecowboy said:

3. How can I retrieve my Sulfuric once my dilution process is complete, do you have a tutorial on it ?

Click to expand...

Once the concentrated portion of the electrolyte turns deep green or blue it's time to regenerate. Let it settle overnight then siphon off the concentrated colored electrolyte into a second clean cell container. Use your lead electrode as the positive (this is opposite normal cell operation) and a smooth hard graphite block as the cathode (negative). Hook up the cell as usual and the copper and other base metals will begin plating out as a red to dark brown colored colored mossy/spongy mass. Periodically remove the graphite block and scrap the spongy material into a separate tupperware container.

This moss will need through rinsing with tap water to remove the acid and soluble sulfates. When the rinses no longer test acidic to pH paper you have rinsed them good enough. Add the first three rinses to the dilute rinses from the previous step. Wrap the rinsed moss in about four coffee filters and twist the top. Squeeze the filter ball until no more rinse water is liberated. Break up the ball of metal powder and let it air dry in the sun.

Here's a shot of some properly rinsed and dried copper powder:



When the production of moss is no longer significant the color of the solution should return to the original color of the electrolyte (clear to yellow tinted). Transfer this acid into a casserole or beaker and cook it down until it no longer loses any volume (Temperature should reach 300-310 C = 95%+ sulfuric acid).
BEWARE this acid is very dangerous when hot and should be handled when completely cooled down to room temperature and with all the proper safety gear as per the MSDS.

In a separate casserole or beaker boil down the combined diluted electrolytes and rinses. Once its reduced to 1/8 to 1/4 it's volume perform the same steps listed above to remove the colored base metals from the solution as mossy metals. Continue concentrating as above (300-310C ) after the mossy metals are removed.

limestonecowboy said:

4. Any ideas on a melting torch as i dont currently have access to oxy/acet- maybe something for the future. Are portable propane/oxy any good, I have seen a Rothenburger kit on ebay for about £50, any use and are there other cheaper alternatives to Oxy/acet ?

Click to expand...

Building a well insulated propane furnace may be cheaper than an acetylene torch rig. MAPP gas plus oxygen works also. Or you can buy one of my Mini-firebricks to melt the gold with MAPP gas only!

Don't melt the black powder until you have refined it by dissolving and precipitating with SMB. The black powder may have considerable amounts of silver or other insoluble sulfates in it.

Steve

Thanks Steve,

That is a very comprehensive reply, what more can I say but Awesome, cheers !

I will post my results when I get to the stage of melting, but I recon I've still got another 8-10 hours on my cell before I attempt to recover the products.

That will give me plenty of time to prepare for, and prefect my rinse and precip process. I dont want to mess them up when I've put the hours in.

I've also been practicing my melting techinque with tin oxide powder and a blow lamp, learning how to melt without blowing out the powder, a must for me before I try it on the real thing.

I may well go for an oxy/acet torch but they run at about £250 for a second hand setup over here, but I may get lucky.

Thanks once again. Rich

1. How do I decide when the cell is 'full'

Click to expand...

The amperage will go to zero when the gold is completely stripped. When the solution is "full" of gold, the amperage will not go to zero. This is due to the gold powder saturating the solution.

2. Do I need distilled water for rinsing my sludge or will tap water suffice ? I am using distilled for storing my lead cathode as instructed.

Click to expand...

The only time distilled water is needed is when you're dealing with dissolved silver, period - no exceptions.

3. How can I retrieve my Sulphuric once my dilution process is complete, do you have a tutorial on it ?

Click to expand...

Allow the black gold to settle and then carefully pour off the acid, for reuse.

4. Any ideas on a melting torch as i dont currently have access to oxy/acet- maybe something for the future. Are portable propane/oxy any good, I have seen a Rothenburger kit on ebay for about £50, any use and are there other cheaper alternatives to Oxy/acet ?

Click to expand...

The black gold should then be dissolved in aqua regia and refined, before melting.

Hi Rich,

I never realised you could go prospecting for gold in the UK!

I'm not too far from Deryshire ( I live in Yorkshire ), can you recommend any sites for a complete beginner?
It's something i've always fancied having a go at.

Best regards
Buzz

Hi Buzz,

Yep I will PM you with some info and sites. I will gladly give you some tuition and advice on equipment if you need it.

Try - http://www.scottishgoldprospectors.co.uk

A great forum site with some real characters.

I am hopefully going panning this weekend comming - 26 27th in Wales.


Best wishes,

Richard.

Hi Richard,

Thanks for the info, appreciate it.

Kind regards
Buzz

Simply amazing:
I went to lazersteves search page, typed in "filter sulfuric" and hit search.
This thread was 4th on the list.

It has answered my questions completely without creating a new post on the operation of my electrolytic cell.

Why don't members tell people about using the search feature for information :shock:

Thanks for the answers
Tom C.