I'm thinking of having a go at making some 999 silver using the nitric acid method. Anyone been there? Any tips? Any suggestions for better methods?
I've not tried any of this myself, but if you weren't before, using electrolysis will produce a much, MUCH greater quality product. I'll have a look around to see if I can find a decent video on it.
A little bit of basic knowledge on electrochemistry would definitely be helpful if you want to do this. [youtube]http://www.youtube.com/watch?v=McbJPWgkqi4[/youtube]
I think you have to disolve it in Nitric acid and precipitate out the silver before you can use electrolysis. Silver and copper are too close to each other on the Electromotive force scale so electrolysis can't be used to seperate them. It is very long and involves acids, chemical waste, electricity and flames. If there is one project not for the beginner I would say this is it but Youtube is full of it and http://www.goldrefiningforum.com/ is an absolute wealth of information and you will probably see an old post of mine where I ask about refining 50% pre dec.
I've done it using nitric, then precipitate out using copper. It's easy if you have the right gear. If you use clean gear and demin water, the end product will be very close to or at 999 silver. It actually doesn't take very long at all. Tips: Do it outside, and don't inhale any of the brown gas that is emitted - the fumes that nitric emits when digesting metals can leave permanent damage to your lungs if inhaled. Use nitrile gloves - nitric does funny stuff to your skin if it comes in contact, like peeling it off. Use protective eyewear - nitric will burn your eyes out if you get splashed. Dilute the nitric to about 30%, and go steady, slowly adding the metal as it is consumed. If you dump it all in in one go, it will froth and boil over very quickly, and you will lose all your silver.
Yep, it will work with 50% no problems at all. The only trouble you will run into is if your 50% contains tin. Nitric doesn't like tin - it forms insoluble metastanic acid which complicates the refining process. There are solutions to deal with this, but it is a pain in the ass However, I have not encountered tin being used in coins, so it should be OK. It is honestly very easy. Like all chemistry, cleanliness and the right gear is key.
This is very informative, on the subject. http://www.recyclingsecrets.com/free-reports/refining-precioius-metals-waste-cm-hoke.pdf
I've done it/ still do it when I get enough junk silver. I haven't set up a silver cell, just cement with copper. The biggest problem you will have is buying Nitric acid. If you live in a capitol city you might find a suppler willing to sell in 1 or 2L bottles for <$200 pick up. http://www.ezylab.com.au/chemicals/nitric-acid-70-2-5-ltrs-ar-grade.html Expensive stuff. I distill my own from sulfuric acid + potassium nitrate. http://sciencesupply.com.au/shop/organic-chemistry-kits/147-organic-chemistry-kit-b14.html view the legal disclaimer. don't bother ordering if you live in QLD. As for where to get the kno3 and h2so4. have a look around and see what you can come up with. I'm not going to post my suppliers publicly.
Holy %hit!!! Nitric for <$200 !!!!!!! The place I am involved with ATM has access to Nitric (%70) 2.5L bottles for $23. They let me take it for nothing. Sulfuric containers are measured in 1000's of litres, and is cheaper than water so they let me take it too.
Cheers wrcmad I'm in central Vic.. Haven't located a supplier here. Have located two Melb companies who are happy to supply, and looking at the above posts ... at very fair prices. If you google "nitric acid" you may find a Melbourne supplier who will post nitric acid after you've provided some details. Also there is a Melbourne supplier listing on ebay. Must pick up though.
BTW thanks to all for their contributions ... I'm enjoying this very much. Wouldn't it be nice to have a mega silver stackers meet ... a huge catch up and get to know each other a bit.
can i join the fun as well.. i have gathered a lot of computer parts, and waiting for the day to do the refining.. still having hard time finding the chemical supplier.. at a reasonable costs.
Try Rowe Scientific for nitric, not sure if they have an outlet in Vic. For gold refining you will need a couple of other chemicals: Any pool shop will have Hydrochloric. Home brew shop for SMBS You will also need some good chemical filters - Rowe will likely have these too. I have done a few big batches of PC's for gold, and can tell you which components the worth-while yields will come from - CPU's, flatpacks, and fingers. The rest I wouldn't bother with.
The Gold refining forum recommended the 50% silver coins as being ideal for making the electrolysis bath. Most of my pre dec coins are disgustingly filthy, I figure that by the time I have disolved them they I should be able to filter the solution and get most of the solid waste out. Any disolved grease shouldn't be an issue after that I hope. +1 to a stakers/makers meeting. Morning spent disolving scrap silver and precipitating it out, followed by morning tea and electrolysis to pureify it further, then lunch and casting bars. Sounds like a nice way to spend a day, we can hold it close to a hospital just in case.
This is the best thread in about 6 months I reckon. Realising I have scrap, acids etc. Just been getting into playing chemist in another hobby and haven't cast a bar in almost a year. Massive thanks for the motivation to give it a go
