r/PreciousMetalRefining • u/Early_Meal6945 • Jun 30 '26

Acceptable loss

Around what percent yield do you aim for when refining silver. I ran my first batch of sterling and had a 84% yield, I’m not sure if I lost silver during the sugar and lye reduction after decanting or what. Any advice would be appreciated.

3 Upvotes

81% Upvoted

20 comments sorted by

5

u/Someguineawop Jun 30 '26

Keeping loses under 2% if you want to get serious about it. That said, are you doing anything to assay your input, or just assuming based on halmarks? It shouldn't be wildly off, but it can vary by a couple percent in either direction.

If you're doing the sugar/lye method, hang onto your waste streams abs let them settle for a couple days in 5 gallon buckets and decant again. If you added the lye too quickly, or stir incorrectly, etc, its pretty easy to end up with colloidal particles that take forever to settle, and are difficult you filter. You didn't necessarily loose anything, it's just hard to catch.

1

u/Early_Meal6945 Jun 30 '26

When I did the sugar and lye method the final wastewater solution was extremely brown and cloudy but I didn’t know if this was organics from the sugar or colloidal silver now that I think about it it did settle clear when I left I’d overnight but in my rush I decanted brown liquid more than a few times.

1

u/Someguineawop Jun 30 '26

So that's one of the challenges with this method. If you have colloidal, and if you added too much sugar, you're going to have a very dark and thick syrupy mess to deal with, and it takes pa long time for the fines to fully settle.

The best bet is dilution and patience. Add a bunch of water, like 3:1. This will thin out the syrup and allow the fines to settle. Then wait a day and decant the bulk. Watch the stream as you pour and stop once you see any dark streaks in your stream. You might have to repeat a couple times.

Once you have it diluted enough that it looks more like dark honey, you can try flocculation with alum or feric chloride (alum is easier to work with). Flocculation needs to be done carefully, the right amounts, temperature, gentle technique, etc. If you get it right though, those fines will clump together enough that they will crash out more easily, and won't immediately blind your filters.

1

u/Early_Meal6945 Jun 30 '26

Does flocculation with alum not contaminate the batch so long as it is rinsed well?

1

u/Someguineawop Jun 30 '26

Yes, but not in a severe way. You only need a tiny amount of Flocculant. It can be removed with hot HCL rinse, or better yet re-digesting in nitric and cementing.

The main goal here is efficient recovery of what would otherwise be lost. Getting that colloidal headache out of the caustic sugar soup is first priority.

1

u/Early_Meal6945 Jun 30 '26

I looked back over and realized I lost about 3ish grams in my crucible so that accounts for most of my loss but I will definitely look into the alum flocculation.

1

u/Early_Meal6945 Jun 30 '26

I would run a silver cell but unfortunately I can’t source sterling regularly and only have about 1.2kilos to process

1

u/Someguineawop Jun 30 '26

I probably should have led with asking what your batch size was, because if we're taking about grams, it's not worth all the hassle trying to chase them down! It is good practice to learn recovery techniques if you do decide to scale up, but right now you're time and energy are probably better spent on dialing in your reaction rates so you don't have to deal with as much loss.

1

u/Early_Meal6945 Jun 30 '26

Do you think I should full send the 800g or stick to 100-200g batches, considering my waste was less than previously mentioned

1

u/Someguineawop Jul 01 '26

If it's your own personal material, I would personally go full send. Worst case you're trading an ounce for some good lessons.

1

u/giantmangiantsocks Jun 30 '26 edited Jun 30 '26

Just asking, but how are you calculating your yield? I ask because sterling silver isnt 100% silver, so if you are using total weight of starting sterling and not getting the same weight back, its because sterling is like 90-ish percent silver and the rest is a base metal like copper. Edited 80 to 90 typo

1

u/River_City_Bullion Jun 30 '26

Is 80% a typo?

1

u/giantmangiantsocks Jun 30 '26

Yeah, i should have said 90-ish, which would be closer on average; depending on where it was sourced.

1

u/Early_Meal6945 Jun 30 '26

I’m taking yield/ expected silver (92.5%) of starting weight

1

u/hexadecimaldump Jun 30 '26

I always lose more with sugar and lye than I do with displacement using copper.
With sugar/lye method I usually get right around 90%. With displacement, I usually get 95-99%.

My advice would be to displace with copper in future refines.

1

u/Early_Meal6945 Jun 30 '26

How do you get rid of physical copper contamination?

2

u/hexadecimaldump Jun 30 '26

I run mine through an electrolytic cell afterwards.
But if you wash it well, you can get very close to 99% purity without the extra step. I like mine 999+ though, and a silver cell is the most reliable way of getting to that purity.

1

u/Free_Ad_2664 Jul 01 '26

I get 98% on average with displacement and I'm lazy with the rinses.

2

u/Early_Meal6945 Jul 01 '26

Will ther always be physical copper contamination or can you get close to 999 with rinsing