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notehunter494

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Dec 26, 2020
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15
Hello and I want to thank All involved in the set up and maintenance of this forum, it is Excellent! I have been going through it for the past 2 months on and off and learned a lot.

So I guess I am coming to you all with two questions, first how to prep my material so I can get it into a button or ingot form and, second how do I separate the metals from each other.

I'm just an old retired jeweler looking for guidance before I start. I had a small mfg. biz doing start to finish production and custom work in primarily 18k yellow gold and platinum. Early on I set up a separate bench for platinum only, but there is platinum in the lot from before I did this as well as some silver from model making and a little "who knows what" from repairs etc. on mostly fine karat stuff. I have approx. 1200g of jewelers' bench tray filings. All the "good stuff", clean metal sprues and prong clippings, have been removed and are long gone. There is a lot of rubber abrasive and pumice wheel dust and the abrasives associated with them along with emery paper dust etc., anything used to clean up castings and assemble jewelry.

I read in Hoke's book about the lye method and the fry pan incineration. She said chose one or the other but not both. The setters I knew would do the lye method monthly, as I recall their material was cleaner than my stuff, so I am leaning towards the fry pan method. I remember reading somewhere you can do both but need to do a mild acid rinse in between the treatments?? From "4metals" post from 9/22/16 they say to rinse the ash with nitric acid and distilled water. Would that be a mixture of the two (diluted acid) or a one, two step process, and can that be done in the frying pan. Would it be to my advantage to do this in several smaller lots? I have a small casting burn out oven, could this be useful? I have read that the sweeps may be laid out on small stainless-steel trays and stacked in the oven for a burn out. I am working in the garage/outdoors, l have no fume hood but I do have a good fan and I am using a map gas/oxygen Hoke torch. I have a BS in biology with some chemistry background and experience melting buttons from the "good stuff" 20-40 DWT, to bring to the refiner. My goal is more to recover than refine. I just want to be able to separate the gold from the platinum group metals and the silver. I would rather use the salt water method than acid refining. Yes I know I am no fun but you see I have experience using acids and believe me I am not set up for the use of concentrated nitric acid and AR.

I have not seen it mentioned here and I am almost afraid to bring it up as it seems to be the elephant in the refining room but is anyone familiar with the "Ishor International" refining systems? I knew a master jeweler who bought one in the early '80's using the salt water method and it worked great for him, the only reason he quit using it was he was making so much money as a jeweler he just didn't have the time to do anything else. Many of the "chemicals" they use have been updated and I put chemicals in parenthesis because you really do not know what you are dealing with, it is sort of a kids easy bake oven system for adults. Does anyone here recommend this salt water and electricity system? I know it's about a grand to buy but looking at what I have to get through I am thinking it might be the way to go, especially to curtail the losses that come with inexperience, and the fact that this is a one-shot deal and not an emerging vocation for me.

I am hoping this forum can give me the kick in the pants I need to get started as my family is tired of me talking about it for the past 20 years. Many thanks in advance.
 

nickvc

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Sep 14, 2009
Messages
4,937
Location
birmingham
For what it’s worth my advice is to incinerate your material, then simply melt the resulting material and have an assay done on the resulting bar taking drilling’s from both sides top and bottom, as you seem to want to avoid acids I can see no other way for you to get the values paid for, with platinum and gold in the mix you have some very unresponsive elements to try and recover without strong acids.
 

notehunter494

Member
Joined
Dec 26, 2020
Messages
15
Thanks nickvc for the quick response. I know that I can do that as a last resort. I would rather try the separation using salt water and electricity. I understand the acids involved are not as strong. Anyhow I just put the cart before the horse. At this point I would just like to get a proper incineration. Any tips or old posts that I might be directed toward would be a great help. I did do quite a bit of looking off and on. With spring coming I am thinking about really tackling this. Thanks again. notehunter494
 

notehunter494

Member
Joined
Dec 26, 2020
Messages
15
For an overview:

Okay moving glacially but I have my incineration done. 1236 gram start 1199 gram finish, pretty clean stuff. I used my burnout furnace rather than all at once in the fry pan and I think I am glad I did. The amount of smoke generated in a one shot deal would make me uncomfortable.

For about a third of the material I moved the heat up to High in three 15 minute increments and left it on high for an hour to and hour and a half, then back down. I had a bunch of small marble bathroom tiles cut in half from a renovation project to use as shelf spacers. The high heat was killing the tiles and I recall reading that the process is pretty much done when the filings stop smoking. The high setting was giving me a good red color and I did not think I needed that much heat so for the remaining 15 burns I brought the furnace in increments up to the setting just under High, dull red, for 45 minutes. I would crack the door to release the smoke every 5 minutes at the middle setting and the smoke was pretty much done by the time I would go to the higher temp so I think I am alright and the tiles held up much better.

22 four shelf burns in 11 days, a lot of time in the garage. I cut the shelves from 2.5 inch 20 gauge 304 stainless sheet, yes I am a nut.

I have two questions:

1) I did keep the first third separate because I recall reading that if you incinerate the filings at too high a temperature it is not good, and when I realized that it would stop smoking at a much lower temp I got worried. Can I mix this high temp treated group with the rest for processing or did I create a problem?

I am ready to mortar and pestle the results. I have in hand a 5 lb cast iron mortar and pestle and somewhere I have a large porcelain mortar and pestle. Am I alright with the iron or is that a problem?

Many thanks in advance, notehunter494
 

notehunter494

Member
Joined
Dec 26, 2020
Messages
15
Hello to all. Yes I am still at it and learning exponentially so I am writing this to anyone who happens upon it and for myself.

A big shout out to sreetips aka kadriver. A picture is worth a thousand words and a video...well a million words. Just to watch and listen to this gentleman as he goes through the procedures and his thoughts and opinions and honesty with his knowledge and experience as he goes has inspired me. It all brings me back to my days of college chemistry, the procedures and goals and titrations, electromotive series and chart of electronegativities, getting reactions to go to completion whether you are denoxing or dropping metal. To see him go little by little to get solutions in proportion at a ml level that will get a reaction to go to completion based on the weight of the metal is inspiring. And the "eyes wide shut" things you can observe in his videos from a master at work that would never be mentioned in text because such items are second nature to the expert but sooo invaluable to the new comer as the devil is in the details. sreetips videos have made all the difference.

I am still here regularly as I gather my necessary equipment and things that will have to be custom made. I realize that it is a to my advantage that my starting material is known and consistent. I can start small, very small, and as I learn exactly what is in these filings, beside sterling silver 14k 18k and Pt alloys, I can up the amount I process. I would be comfortable to work in one ounce lots and will scale my operation to meet this size goal. I will keep you posted as I go.
 

Alabama938

Well-known member
Joined
Feb 13, 2021
Messages
84
I don’t think the material of the mortar and pestle matters much. This is a neat post, can we see some pics of the material with next post? There’s a million posts on here about those easy bake oven type refining kits, they all seem to end with cementation aka reset button. There’s a reason sreetips does it the way he does, simple chemistry done carefully and well, yields consistently excellent results. Kind of like Italian food.
 

nickvc

Well-known member
Joined
Sep 14, 2009
Messages
4,937
Location
birmingham
I still think you are going about this the wrong way especially with the mix of metals you expect.
Now you have incinerated your material depending on the silver content you could dissolve the silver in nitric and remove the platinum group metals and many other base metals at one go, as the palladium will dissolve in nitric and platinum will also dissolve in nitric if there is enough silver present.
The remaining material will have some PGM contamination but hopefully not much and because it is now in small particles will easily dissolve in HCl with either bleach or hydrogen peroxide as the oxidizers.
This whole batch could be processed in a day.
 

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