What to do with Anode Basket Slimes

[nickvc]

The reason the PGMs are in solution is because of the presence of silver so I doubt silver will actually cement the PGMs out of said solution , I may be wrong, but as I said earlier if you want to recover the PGMs convert the silver to chloride and filter off and then cement the PGMs with copper.

 

[Ayham Hafez]

Per the bold print (salt peter) - NO - salt peter is potassium nitrate - when smelting any kind of material that has silver in it (such as ore containing silver, silver plated copper/brass, silver slimes from silver cell etc. etc.) you never want to use potassium nitrate (or any other nitrate) as part of your flux ingredients

The reason for that is that nitrates used as a flux ingredients basically become nitric acid at the high temps of smelting - so when the flux becomes molten - any metals in the smelt - that will dissolve in nitric acid - will then also be dissolved by the nitrate in the flux causing (at least some of) those metals to then go off in the slag

So - using potassium nitrate - as a flux ingredient - is a good option if you are smelting gold with copper in it as the nitrates will dissolve the copper & thereby allow the copper to go off in the slag

You just don't want to use potassium nitrate (or any other nitrate) - as a flux ingredient - if what you are smelting has metals in it that will dissolve in nitric acid - metals such as silver or palladium - as those metals will dissolve in the smelt & go off in your slag - instead of collecting with your dore (alloy) that you are wanting to settle in the bottom of your cone mold when you make your smelt pour

Kurt

In this video at minute 53:00 he got the zinc slag from Parkes process and mix it with 500 g soda ash, 500 g borax and 250 g potassium nitrates, not sure about the zinc slag weight but I think it should be less than 1 kg since he mentioned he used 5% zinc from total weight of lead alloys. I don't know how much potassium nitrate needed to oxidize 1kg of zinc but based on density I think 250 grams of nitrates able to oxidize more than 1 kg of zinc, at the end he got 70 grams of impure silver and after cupellation he got 54 grams of silver which mean the silver content in the lead ore is more than 2000 ppm which is a high grade ore.

I didn't test potassium nitrate yet, but from Jason video it seems that silver not oxidized by potassium nitrate, but from my experience in melting silver in small scale,when we use oxidizing flame the silver will oxidized but will not be separated with slag or as a matt shape, it will just stuck into the silver dore but with irregular surface.

 

[Yggdrasil]

In this video at minute 53:00 he got the zinc slag from Parkes process and mix it with 500 g soda ash, 500 g borax and 250 g potassium nitrates, not sure about the zinc slag weight but I think it should be less than 1 kg since he mentioned he used 5% zinc from total weight of lead alloys. I don't know how much potassium nitrate needed to oxidize 1kg of zinc but based on density I think 250 grams of nitrates able to oxidize more than 1 kg of zinc, at the end he got 70 grams of impure silver and after cupellation he got 54 grams of silver which mean the silver content in the lead ore is more than 2000 ppm which is a high grade ore.

I didn't test potassium nitrate yet, but from Jason video it seems that silver not oxidized by potassium nitrate, but from my experience in melting silver in small scale,when we use oxidizing flame the silver will oxidized but will not be separated with slag or as a matt shape, it will just stuck into the silver dore but with irregular surface.

Jason has never been very concerned with losses in any of the videos I have seen.

 

[Ayham Hafez]

Jason has never been very concerned with losses in any of the videos I have seen.

I make a search on Cerro Gordo mine

https://www.mindat.org/loc-27431.html

Silver grade is about 1000 PPM, for sure Jason sample taken from main vein this is why he got higher rate, anyway the main idea if potassium nitrate make silver loose he will not get such amount, with 250 grams of potassium nitrate in a sample we have seen he should get no silver at all!