I know its expensive but

[Ian S]

I am trying to set up a semi-professional space to do AR long term. I was eyeing this hood:
https://www.fishersci.de/shop/products/bel-art-scienceware-clear-view-fume-hoods-2/15564034

What corrosion free fan should I be looking for to go with this?

 

[4metals]

Yes you need a corrosion resistant fan but first about this hood. One it is expensive, and 2 it is tiny. What quantities of aqua regia work are you looking into doing? Are you looking to refine gold alone or some PGM's as well? Because the capacity of this hood, for a semi-professional space is limiting.

 

[Ian S]

Yes you need a corrosion resistant fan but first about this hood. One it is expensive, and 2 it is tiny. What quantities of aqua regia work are you looking into doing? Are you looking to refine gold alone or some PGM's as well? Because the capacity of this hood, for a semi-professional space is limiting.

PGMs as well. Small amounts at a time. Lets say max 200g (is that small?) Any recommendation

 

[4metals]

Look at a few of Sreetips video's, he is a member here and makes excellent video's. his channel is here.

His hood is 2 feet by 2 feet and you can see it is tight for what he does. His hood is a Labconco hood that actually comes with a blower as part of the assembly. I am not sure if they even make them that size anymore.

I actually have a hood like that in my basement that I used when I was consulting for in house testing. It is tight to work in but spacious as compared to what you posted.

 

[4metals]

Take a moment to describe where you want to be with this processing in a few years. How big can your refining process actually become, and how much space do you have? And where is your place of business located, not specifics, just general will do. It is quite possible you can build a larger setup for much less than buying a fancy Labconco system. And have room for future growth.

The reason for asking the where question is because environmental regulations usually allow for a de minimus status for small operators generating under a specific quantity of NOx waste at any given time. In the USA that is 10 pounds per day of NOx. Let me tell you, you can digest a lot of metal in that much aqua regia (about 140 ounces if done optimally) But the catch is you need to register your business and apply for de minimus status. And included in that is the fact that any neighbors complaining about smells or red clouds can have your status removed. Which means you need to scrub your fumes if it offends anyone.

So if you are in a rural setting vs. the inner city, you may have options.

 

[Ian S]

Take a moment to describe where you want to be with this processing in a few years.

My main income is not from refining and probably never will. I am just trying to get a bit more of the profit margin that the large refiner takes away form me here. I mainly produce jewelry, so I run a small casting operation.
I have no plans to get "large" but I would like the most "professional" and efficient setup possible from the beginning. I am in central Europe. Not completely rural so a scrubber will probably be necessary. My workspace for this will not be huge. Lets say the 170cm x 70cm table. of course I could expand that a tad.

 

[4metals]

You are essentially looking to set up a small refining hood in your casting room. I have seen many jewelers in NYC cram a lot of refining into a small space. The easy part is to refine by inquartation and continually recycle the same Silver and incorporate the 99+% pure gold back into alloy. This can be done easily with a small scrubber column and a few beakers and a hot plate. Not really needing aqua regia, just nitric.

The Platinum refining will be more of a challenge but nothing that cannot be done. I assume you already have an area with exhaust where you melt alloys so the space for refining is just that, for refining.

To be willing to take this on you must really feel you are being over-charged by your refiner. What kind of rates do you pay, and what kind of losses do you think you are having?

 

[Ian S]

You are essentially looking to set up a small refining hood in your casting room. I have seen many jewelers in NYC cram a lot of refining into a small space. The easy part is to refine by inquartation and continually recycle the same Silver and incorporate the 99+% pure gold back into alloy. This can be done easily with a small scrubber column and a few beakers and a hot plate. Not really needing aqua regia, just nitric.

The Platinum refining will be more of a challenge but nothing that cannot be done. I assume you already have an area with exhaust where you melt alloys so the space for refining is just that, for refining.

To be willing to take this on you must really feel you are being over-charged by your refiner. What kind of rates do you pay, and what kind of losses do you think you are having?

for example here with the platinum, for every 100g platinum scrap I refine I have to pay about 594usd! For 100g gold scrap its about 180usd...That adds up every week

 

[4metals]

For the 18 karat scrap the charge is about 3.1%, not bad actually considering the lot size. The Platinum is 4.9%, again for a small lot. This is all head math so I should check it. Anyway over $700 per week is a lot to give up.

Depending on what you spend on nitric acid, which may be a lot if you pay what small users in the USA pay, you should be able to save some serious money refining in house. Before you get too far along check out the price you will need to pay for nitric acid. That may be the make it or break it factor.

 

[Ian S]

For the 18 karat scrap the charge is about 3.1%, not bad actually considering the lot size. The Platinum is 4.9%, again for a small lot. This is all head math so I should check it. Anyway over $700 per week is a lot to give up.

Depending on what you spend on nitric acid, which may be a lot if you pay what small users in the USA pay, you should be able to save some serious money refining in house. Before you get too far along check out the price you will need to pay for nitric acid. That may be the make it or break it factor.

Ill get some quotes tomorrow. What purity am I looking at? And I assume ill be buying by 10l and not 1l at a time, right?

 

[Ian S]

For the 18 karat scrap the charge is about 3.1%, not bad actually considering the lot size. The Platinum is 4.9%, again for a small lot. This is all head math so I should check it. Anyway over $700 per week is a lot to give up.

Depending on what you spend on nitric acid, which may be a lot if you pay what small users in the USA pay, you should be able to save some serious money refining in house. Before you get too far along check out the price you will need to pay for nitric acid. That may be the make it or break it factor.

From what I see now about 10usd a liter for 30%

 

[andu]

10 usd ain't bad imo, and if you do nice setups you can save a lot of it. I find that fume hood too small that will become like a tiny aquarium you'll want to keep growing till you hit 10000l.

 

[4metals]

From what I see now about 10usd a liter for 30%

That is over twice the internet price for bulk that refiners pay in the USA.

This price may put refining by inquartation out of reach for you. Still do able but aqua regia uses substantially less nitric acid if the Silver in the alloy is low enough.

What percentage Silver is in your 18kt alloy you make? Or what is the highest % silver in any alloy you make?

 

[Ian S]

That is over twice the internet price for bulk that refiners pay in the USA.

This price may put refining by inquartation out of reach for you. Still do able but aqua regia uses substantially less nitric acid if the Silver in the alloy is low enough.

What percentage Silver is in your 18kt alloy you make? Or what is the highest % silver in any alloy you make?

16% is the highest Ag in the Yellow alloy I use. The white alloy is 13% Pd. Not sure if the latter plays a roll
5-10k would be my budget for a refining setup here.

 

[Ian S]

That is over twice the internet price for bulk that refiners pay in the USA.

This price may put refining by inquartation out of reach for you. Still do able but aqua regia uses substantially less nitric acid if the Silver in the alloy is low enough.

What percentage Silver is in your 18kt alloy you make? Or what is the highest % silver in any alloy you make?

I found a better price. comes to about 4usd per liter of 30%

 

[4metals]

16% is the highest Ag in the Yellow alloy I use.

This level of Silver will not refine easily in aqua regia as the high Silver will coat over the gold as silver chloride and not allow the aqua regia to do its job. Your only option here is to inquart with silver and part with nitric acid. Anything over 7.5% Silver will cause alloy to coat over and not dissolve completely. Not that you lose the gold, but it is harder to get it to the purity you seek. Does your refiner pay you for the silver in the material you ship to them?

The white alloy is 13% Pd.

The Palladium is soluble in aqua regia and in nitric so you have options depending on the silver content of the alloy for the same reasons listed above. If the method you choose to process the white alloy is inquarting, you will need an additional step before you recover the Silver you use to inquart the gold.

 

[Ian S]

This level of Silver will not refine easily in aqua regia as the high Silver will coat over the gold as silver chloride and not allow the aqua regia to do its job. Your only option here is to inquart with silver and part with nitric acid. Anything over 7.5% Silver will cause alloy to coat over and not dissolve completely. Not that you lose the gold, but it is harder to get it to the purity you seek. Does your refiner pay you for the silver in the material you ship to them?


The Palladium is soluble in aqua regia and in nitric so you have options depending on the silver content of the alloy for the same reasons listed above. If the method you choose to process the white alloy is inquarting, you will need an additional step before you recover the Silver you use to inquart the gold.

Yes they pay for the silver. Inquarting it is then.

 

[4metals]

5-10k would be my budget for a refining setup here.

This is doable for a modest setup like you are thinking about. The main thing here is your hood and your scrubber. Both can be made by a reasonably DIY capable refiner. Then it's just glassware and chemistry.

You will find that perfecting the process for the lot sizes you currently generate will empower you to scale up your operation modestly without much expense and take in refining lots from other jewelers. The process scales up easily especially if your lot sizes remain modest.

You will want to segregate your platinum group alloys from your golld and silver only alloys for processing.

Keeping this in mind, you will find that the gold refining forum is your friend. We can and will help you through the entire process as long as you provide details of your needs and progress so we can help. Threads like these can help many members.

 

[Ian S]

This is doable for a modest setup like you are thinking about. The main thing here is your hood and your scrubber. Both can be made by a reasonably DIY capable refiner. Then it's just glassware and chemistry.

Much appreciated. I will do a ton of reading.
Im not totally against DIY but I am so busy with other things that if its something I could throw a bit of money at (scrubber, hood) and to have it delivered working, id be interested what options you would suggest.

 

[4metals]

You will get some benefit from this thread, the OP is a Vietnamese gold buyer who had a similar issue and we walked him through the process and to some extent the setup. Check it out here.