Intensive vs extensive processes

[stella polaris]

Most processes described in this forum are intensive and takes a maximun a couple of days. This makes sense for companies and others that must have a constant flow of material and can not afford to lay on large values in the process. For a amateur like me, that saves the values, its less important to have a fast overturn. Therefor my question about extensive processes that can take months but works.

I have the feeling that it should exist processes that works, are cheap and give a good yield without producing to much waste. However they do not fit the professional recover/refiner. AP process can be said to be one. But are there more? I personally can accept processes that takes up to one year.

 

[Martijn]

To save on nitric use (precursor for explosives and thus getting harder to buy every day) I'm exploring if electrolytical 'dissolving' of solid sterling silver will work in the H2O cell.
Then converting to AgCl to isolate tge silver and wash bm's off followed by sulphuric/iron or sugar/lye to elemental silver.
It may present some challenges to get the last silver dissolved as objects are getting smaller by disssolving, but it's another slow, low acid use option and imo therefore interesting enough to investigate.
When nitric is no problem but time is, the silver nitrate cell is the best option for sterling silver as I understood from the experienced professionals.

 

[Yggdrasil]

Most processes described in this forum are intensive and takes a maximun a couple of days. This makes sense for companies and others that must have a constant flow of material and can not afford to lay on large values in the process. For a amateur like me, that saves the values, its less important to have a fast overturn. Therefor my question about extensive processes that can take months but works.

I have the feeling that it should exist processes that works, are cheap and give a good yield without producing to much waste. However they do not fit the professional recover/refiner. AP process can be said to be one. But are there more? I personally can accept processes that takes up to one year.

The AP is one of these processes, there may be others though.
So if anyone has something, please keep it coming.

 

[stella polaris]

To save on nitric use (precursor for explosives and thus getting harder to buy every day) I'm exploring if electrolytical 'dissolving' of solid sterling silver will work in the H2O cell.
Then converting to AgCl to isolate tge silver and wash bm's off followed by sulphuric/iron or sugar/lye to elemental silver.
It may present some challenges to get the last silver dissolved as objects are getting smaller by disssolving, but it's another slow, low acid use option and imo therefore interesting enough to investigate.
When nitric is no problem but time is, the silver nitrate cell is the best option for sterling silver as I understood from the experienced professionals.

Martijn if you are patient you can collect the urea you produce yourself. : ) To boil saltpeter its a old process. In Sweden you could be punished to boil saltpeter in the old days.

 

[Justincase]

Refining metals does take some investment and time to learn, if you are not doing something different every week you might never have the opportunity to learn in the first place.
It is a system in which you must develop your own problem-solving abilities rather than ask other people at every junction.
People will help you a bit but it is quite rude to depend on them to do the work for you.
There are other jobs in the noble metals industry.
People who are refining are kind of stuck in one place and can not really waste time traveling to auctions or going hunting in unusual places.
If you are happy to stockpile great.
eventually, you will have enough to produce a decent-sized dor bar for which you will be paid almost the full spot value in any case.
Though you should still study the technical side of the industry so you can test and value scrap effectively.

 

[orvi]

I do not feel I know much of such processes, but some air oxidations like AP could be considered. I do not see the benefit of doing it that way tho - only to save oxidant of course.
Here on the forum, there is much talk about wet chemistry and few preferential methods of this field, but a lot more to be discovered in pyrometallurgy
If aim is reducing waste - which is very considerable factor - pyro is one of the routes, which tend to concentrate the waste, and even in a form which is not considered hazardous (locked in the slags etc.).

For example sterling could be pyrometallurgically refined - oxidative smelting. You can also replace the nitrate with abundant air - as oxidant. Yeah, probably you won´t be able to easily pass 99%, but essentially copper could be all oxidized away by purging the melt with air, and using suitable flux to dissolve Cu2O/CuO.
Thing is some of the silver tend to dissolve in CuO rich fluxes, but it can be managed. And also, you need the non-reductive crucible - like clay one, or magnesia. No graphite of course In induction, efficient heating could be achieved also without graphite - if you use larger pieces of metal capable of catching induction. Then periodically skim the slag, add fresh flux and continue purging with air. Bubbling the melt through alumina tube is also doable, but the tube suffers from the slag and it is eventually slowly dissolved in it. Metal tubes aren´t preferred as metals like iron which aren´t that soluble in silver reduce the copper back to metal.

Lead/bismuth wash is also very useful tool of getting gold from lowgrade plated ferrous pins or carriers. Very low ammount of waste is produced through the process. Unfortunately, recoveries can go as low as 80% if it is not done right. Additional wash with fresh lead or bismuth is necessary to go more to completion - and this second wash of material could be the starter for another batch - for example.

Transistors with metal cap could be dissolved in straight HCL with heating - another lengthy process, but relatively straightforward, with good recoveries of gold, as it does not pass to high volumes of liquid, and stay as foils.

 

[Yggdrasil]

I think what @stella polaris is asking for is more in the fire and forget class of chemistry, where time are not of great importance.
Personally I do not know of any pyrometallurgical processes in this realm, unless you "own" your own volcano
The AP process is one, putting your magnetic legs from ICs in a bucket outside with a splash of salt and a few drops of HCl for a few months is another.
I'm sure there are more of these self controlling processes that lets you concentrate on other tasks at hand.
So please keep them coming.

 

[orvi]

I think what @stella polaris is asking for is more in the fire and forget class of chemistry, where time are not of great importance.
Personally I do not know of any pyrometallurgical processes in this realm, unless you "own" your own volcano
The AP process is one, putting your magnetic legs from ICs in a bucket outside with a splash of salt and a few drops of HCl for a few months is another.
I'm sure there are more of these self controlling processes that lets you concentrate on other tasks at hand.
So please keep them coming.

I understand, and I have no doubt they exist. But as far as I can see, I do not find them of any benefit. AP happen to be one case where it is beneficial to let the time do the thing - and of course very convenient to let it happen on it´s own.

My point was, there are processes that can be done with minimal effort, minimal "care" and in a fraction of time - so no need to wait week or so to get things done. Mainly if we speaking of pyrometallurgy. Most of the times it is done very, very quickly.

Molten lead bath for lowgrade ferrous pins can have them stripped in few minutes, lead is drained straight to the cupelling dish and "abandoned" in electric furnance for few hours - and you got your bead right there. 5 minutes heating the old stainless pot with pins and lead, 3-4 minutes actual stripping, draining the molten lead through fine stainless steel mesh directly to the cupell, and shoving it inside the preheated furnance - another maybe 3 minutes. After cupelling, you remove the cupel out of the furnance and let it cool down, pry out the bead, clean it... Maybe another 5 minutes. Putting the stripped lead covered pins back to the pot, adding fresh lead, putting it back over the flame and draining the lead after 2-3 minutes to another pot for next batch - another like 10 minutes. So overall your "caring" time is about 25-30 minutes max. Only waste produced are lead covered stripped pins (could be passed to scrapyard) and used cupel. Nothing more. No liters of liquid ferrous waste which is nightmare to filter after pH rise.

Compared to regular AP, where you need to set it up, cover in HCL, stick in the bubbler, let it dissolve completely - what could actually take weeks. Then filter the foils out of the soup and treat the liquid waste with alkali and filter that pudding, and dry it to get it properly disposed - and this is obvious PITA, as nobody (honestly ) like dealing with waste. More chemicals needed to proceed, dedicated space where some HCL vapors wouldn´t irritate anybody or anything... Lengthy filtration of liters of solution...