Hi all, This is my first posting and greatly appreciate any and all help given. I have had no issues with Karat and Vermeil refines. In-fact I love Gold Vermeil and have been doing that for a long time. But I wanted to give Gold filled a try since I have had a stockpile building of it for a very long time. By all accounts everything I had seen and read told me it should progress the same as I do my Vermeil. I have been using Harold's step by step process for that and never had an issue. Vermeil uses way less Nitric and dissolves so easily sometimes I don't even need heat. But then the Gold filled has me stopped in my tracks because I don't want to proceed without some guidance. So I checked all my pieces and found definitive markings of either 10K, 12K, or 14K 1/20 gold filled on all pieces. I gave them a quick torching to glow off oils and grease. I did my calculation at needing 3482ml of nitric to complete the base metals. I had no time constraints so I was going to do small dilute nitric baths and just go till all base metals were gone. Things started great. I was going 700ml distilled, adding 300ml of nitric to start. Got a great reaction of swirling and bubbling. Let that run till it visibly calmed down, added another 100ml of nitric. Let it calm again, and add one more 100ml nitric, then after it calmed let it cool and pour it off and repeat that formula till all base was exhausted. The problem is the first 3 cycles of that ran as predicted, but the 4th started to react with just a bit of brownish yellow fume building up under my watchglass and then nothing. I turned up the heat and still nothing. Since this was from a previously opened bottle of nitric it had me almost thinking my acid could have degraded. So I poured off that solution and opened a new bottle and added a fresh cycle and still nothing. I went and pulled a decent sized Gold Filled chain from my stock and tossed it in the previously poured off cycle of solution(the one I thought could have been degraded acid) but it immediately reacted and dissolved it in a rapid period of time. I took my stirring rod and tossed around what id left in my initial base material beaker and it surely seems to be a lot of material left. A few even seem to be hardly started to dissolve. Plus my Nitric usage had only hit 2000ml which is way off my calculations of what I had figured needing to complete the process. So at the start I was sure I had no stainless in this batch, but now I'm second guessing myself. So what would be my best next step to eliminate loosing any gold I have gotten to this point. And or how to proceed from here. Thanks
Gold filled refine not going as I had hoped
- Thread starter SinisterGenuis
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Nitric will do NOTHING to real higher karat scrap. 10k can sometimes react slowly if it's high percentage copper, from my experience. Did you cut the gold-filled material at least in half? 14K GF may not react at all if it's the higher-quality GF, since the acid cannot penetrate the gold to attack the base metal beneath.
I process Gold Vermeil the same way I am processing this GF. I have never had an issue with the acid penetrating the Gold coating on the Vermeil and its my understanding that the coating on Vermeil is better quality than on GF. I am Following Harold's method and it does not mention inquarting before Nitric. A long time ago in a post I also asked that of Sreetips and he told me it would become colloidal and make it harder to separate.
If you have separated it from its base metals and the rest is over 6 karat it needs to be inquarted in the meaning brought to 6 karat.
You can avoid this if you canntumble it or otherwise remove the coating of Silver Chloride mechanically during dissolution.
Or it is so thin the AR gets to the Gold through the layer of Silver Chloride.
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So in reply to your first sentence thats the hurdle I'm having. I find it hard to beleive that i have in fact removed all the base metals. I also highly doubt any of these pieces were karat gold only GF. If I may ask why would I have silver chloride at the dilute nitric bath stage.
Of course there are karat in Gold filled.
They would never use pure Gold as it is too soft.
And the Silver comes from the karat alloy if you put it directly into AR, which can be done if you tumble or other wise mechanically disturbs it.
I know GF has a Karat layer, But when I use the term Karat gold I only refer to pieces that are solid Karat such as a 14K wedding ring or 18K rope chain. When I refer to GF it is 1/20 10K, 14k, or 18K over base metals. So if I were doing Karat(solid) I would have inquarted, but I was doing GF and thus went right into dilute Nitric. But as I mentioned in my entry post the vigorous reaction that started on my first couple boils suddenly stopped on my 4th nitric bath. As I mentioned I have done gold Vermeil for a long time and never had this issue. The Nitric attacked and dissolved all the silver through the Gold layer. In this case are you telling me GF has reacted differently than that and the Nitric couldn't get to the base through the gold? And when You mentioned Silver chloride I was only aware of getting that by intent when salt is added to precipitate it out of silver nitrate. I am aware of silver in solution because as I mentioned I prefer Gold Vermeil most of all because I have the best of both worlds in separating gold and silver. But I cement out with copper and have never converted my silver nitrate to chloride. Don't prefer to do it that way. But my Big Hurdle right now as I mentioned in my initial entry post is I have a beaker full of partially dissolved GF jewelry that started to react to Nitric and sperate out Base But then stopped and nothing else want to react. I suppose I could pluck out the obvious larger pieces and try to figure out why they stopped reacting and then filter and incinerate the rest take it to HCI and then to AR and see what I end up with. Specifically I noticed 2 woman's bracelets in the beaker that look hardly touched. If these ended up being stainless based, would putting in AR dissolve the outer layer of gold from the Base or would passivation block me. I know with watch bands it has been talked about a lot but I have came across few pieces other than watch bands where stainless was an issue. Very apologetic for the long winded txt but frustration is not my friend. Thanks much
Its actually around 1200 grams. My initial calculation was 3482ml of nitric to dissolve out all base metals. using 3-3.5ml per gram formula. also I have heard of other using a few ml of sulfuric during the HCI baths to get rid of lead and tin. In this case would the presence of Nickel have stopped the reaction at a point where other base metal would also stop being dissolved or just the Nickel itself?
I use the 1/4 formula, it is more practical to have nitric acid in excess than to then stand over a glass and look at the precipitated silver on unetched pieces of brass and copper.
Most radio components contain nickel alloys.
These are caps from iron transistors, gold-plated leads from microcircuits and transistors in plastic cases.
and all use a cocktail of sulfuric and nitric acid.
2 parts sulfur to one part nitrogen.
Most radio components contain nickel alloys.
These are caps from iron transistors, gold-plated leads from microcircuits and transistors in plastic cases.
and all use a cocktail of sulfuric and nitric acid.
2 parts sulfur to one part nitrogen.
So I added a little Sulfuric(2.5ml to my 1200ml solution), and didn't do anything. I saw your last post after the fact. Were you saying you use 2 parts sulfuric to one part nitric?
Seems to be way off the path from what i was originally trying to do(process some golf filled jewelry).
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Did you try cutting the bracelets into smaller pieces, exposing more base metals to the acid?
No actually I didn't, but I think I found the more eluding problem. I had bought a new stirring/heating plate and didn't pay close enough attention to the details. The surface area of the plate is 5 x 5 a little small but I figured all I need is the heat to be focused under center of my beaker. It gets to 767°f and I figured thats plenty, but as it turns out I now realize after reading the data plate it only is 160w heating element and that 767°f is only the surface of the plate with nothing on it. Once my Corning Ware dish and Heavy wall Beaker are added then my IR gun showed my solution was only getting around 90-110°f. I took a cardboard box and opened it up at both ends and used it as a sleeve and placed it over the beaker, Dish, and hotplate and this allowed my solution to reach about 140-150°f. This increased temp started to show reaction in the pieces that had previously looked untouched. I have since ordered a new plate with adjustabilty of 200w-1200w with a surface area of 8x8. Seems my Nitric boils were not anywhere near Boils at all.
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