Washing cement silver using a centrifuge.

[Amol Gupta]

Not necessarily connected, I'm from India and the guy in the video is from a neighbouring country Nepal(If that is some sort of relation).

I did hit him up through social media we had a brief conversation, he told me HCl is banned in his country so the best they can do to refine gold was through inquartation and acid leaching.
I was sceptical as to how do they remove lead from the gold without using aqua regia. Never got to know how that's even possible.

And yes in my part of the world if we get silver purity close to 98.5 or 99% that is good enough for most cases.

And if i.m able to get close to 99% purity from my cement silver I can get rid of the electrolysis process which is very time consuming.

 

[4metals]

Have you seen this thread ?

 

[Amol Gupta]

Have you seen this thread ?

Thanks for the reference, so I did go through the thread and what my understanding is he used copper powder instead of copper bar to cement out his silver which he mentions to be very quick, but I could not find any mention of how he cleans his cemented silver to remove copper nitrate.

 

[Amol Gupta]

Also the video he uploaded is now a private video and cannot be viewed.

 

[4metals]

He did not cover the rinsing he does, he just covered dropping it on powdered copper.

Are you restrained by any chemical discharge limits or other water restrictions?

 

[Amol Gupta]

He did not cover the rinsing he does, he just covered dropping it on powdered copper.

Are you restrained by any chemical discharge limits or other water restrictions?

Well I want to recover my nitric back using electrowinning, pretty sure I don't want to do something barbaric.

And no I'm not limited by any discharge limit or water restrictions

 

[4metals]

Well I want to recover my nitric back using electrowinning,

You want to recover your copper by electrowinning. Nitric is another process.

If you do a preliminary rinse and keep that liquid for recovery of copper or nitric, using an ultrasonic cleaner to thoroughly agitate the particles of cement silver and copper bearing water by cavitation, will put the copper nitrate in the water column and the cement Silver, being metallic, will settle. Doing this to a layer of Silver cement in an ultrasonic cleaner, allowing it to settle, decanting and repeating a few times will do an excellent job. If the settling of the fines takes too long, running the supernatant liquid through a filter cartridge will catch the fines. Clogged filters can be burnt to an ash and the Silver melted and collected in a heavily fluxed melt poured into a cone mold.

 

[Amol Gupta]

You want to recover your copper by electrowinning. Nitric is another process.

If you do a preliminary rinse and keep that liquid for recovery of copper or nitric, using an ultrasonic cleaner to thoroughly agitate the particles of cement silver and copper bearing water by cavitation, will put the copper nitrate in the water column and the cement Silver, being metallic, will settle. Doing this to a layer of Silver cement in an ultrasonic cleaner, allowing it to settle, decanting and repeating a few times will do an excellent job. If the settling of the fines takes too long, running the supernatant liquid through a filter cartridge will catch the fines. Clogged filters can be burnt to an ash and the Silver melted and collected in a heavily fluxed melt poured into a cone mold.

So a couple of terms I had to Google before writting this reply 'cavitation' and 'supernatant liquid's.

So correct me if I'm wrong here, to start of I have cement silver submerged in the copper nitrate solution. I first decant the solution and rinse my cement silver once with water.

Next I put my cement silver in an ultrasonic cleaner and turn it on.
I have to repeat this process a few time(3-4times)is my best guess.
I wait for the silver to settle and thenI decant the water used for washing and pass it through a filter.

The silver stuck in the filter paper can be collected by burning the filter paper in a heavily fluxed melting arrangement and collect my silver from the bottom of the cone mold.

This is my best guess of what you are trying to suggest or what I understand from it.

 

[4metals]

I apologize for speaking a few chemical nerd words but thanks to Google you got it.

The filters I would typically use are spiral wound polypropylene filters in a housing because I would pump off the supernatant liquid. This is an example of the cartridge I am referencing. The cartridge sits in one of these .

 

[Amol Gupta]

I apologize for speaking a few chemical nerd words but thanks to Google you got it.

The filters I would typically use are spiral wound polypropylene filters in a housing because I would pump off the supernatant liquid. This is an example of the cartridge I am referencing. The cartridge sits in one of these .

Ok and then you talk about burning out this filter cartridge in a heavy flux.

Maybe a noob question but how do know when the filter is full/clogged.

 

[4metals]

A filter loaded up when the particles clog the pores and the flow slows to an unacceptable speed. Those filters come in all size porosity from 1 micron to 50 micron so find one mesh that collects your fines and when the flow gets too slow, time for replacement.

If you have an incinerator just toss it into a shallow pan and incinerate it. Without an incinerator put it in a bucket with a little accelerant (not gasoline) and burn off the plastic then throw it in a crucible with soda ash and borax and melt it. Pour it into a cone mold so it all collects at the bottom and run that silver through your process again.

 

[Amol Gupta]

If you have an incinerator

I do have a melting furnace.

toss it into a shallow pan

I do have quite a few melting dishes.


I'm pretty sure this is what you are talking about(in a much smaller scale offcourse).

 

[4metals]

I'm pretty sure this is what you are talking about(in a much smaller scale offcourse

Yes. The cone mold allows the heavier metal fraction to freeze in the point. The steep sides encourage any beads that may linger to migrate towards the bottom as well. When you empty a cone mold and break off the cone, or pyramid in your video, inspect the slag that was close to the metal cone for beads that didn’t make it to the metal cone before it solidified.

 

[grainsofgold]

What was throwing that hot crucible into a quench tank all about?

Wondered the same thing- why didnt it crack ?

 

[Trevor Ward]

Alluminium should work instead of steel as well.

Aluminum is reactive to acids.

 

[Yggdrasil]

Aluminum is reactive to acids.

Yes but...
Aluminum is not reactive to Nitric, since it creates a very strong protective layer.
Hydro Chloric on the other hand is very hard on Aluminum.

 

[Yggdrasil]

Aluminum is reactive to acids.

Welcome by the way.
Some good links to study:

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798
2. Then read the safety section of the forum: https://goldrefiningforum.com/forums/safety.47/
3. And then read about "Dealing with waste" in the forum: https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Suggested reading:
https://goldrefiningforum.com/forums/the-library.101/
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
https://goldrefiningforum.com/threa...le-read-this-before-you-post-about-ore.33333/


Forum rules is here.
https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/

 

[4metals]

Wondered the same thing- why didnt it crack ?

It likely crumbled if it succeeded in breaking off the clinging metallic silver stuck in the crucible. Making it easy to scrape out the loose bits. However I am not quite sure, I have never had the testicular fortitude to throw a white hot crucible in a tank of water. Especially not while I am in barefoot melting mode!