Welcome to the forum!! You seem to have a good idea of what you're aiming to do. Unfortunately, it seems as if some of the eBay people are trying to keep a good man down, or maybe they just don't know what they're talking about
So relax, perhaps make yourself a strong eggnog, take a break and we'll go over this.
buffa1o1 said:
I have have asked a couple of eBay sellers offering advise who had differing opinions about the results of my experiment,
including one that said the percipitated powder will only be red if it is platinum and that Hoke must have been color-blind
because platinum will not percipitate an orange powder as stated in the book.
I've precipitated a goodly amount of platinum, and if you're doing it right, and you're precipitating with ammonium chloride solution, then you will be seeing a canary yellow precipitate. This indicates that everything has gone as well as it could and you've made a very pure precipitate of ammonium hexachloroplatinate. If it is slightly orange, it's passable stuff, but it should still be refined once more. If it's pumpkin orange bordering on orange-red, that usually indicates that there's significant Pd contamination, so try again. Palladium, when precipitated out as ammonium hexachloropalladate, is brick red wet and will take a nice pretty red color as it dries.
buffa1o1 said:
I first dissolved the base metals in heated Nitric acid made from strong Sulfuric acid (Rooto) and Sodium Nitrate. I realize
this was a mistake because I am sure that I also dissolved some Palladium and other pm but saved my solution to re-work later.
Sulfuric acid does attack palladium, especially when it is in finely divided or thin foil form. So too does your nitric acid. If your solution went quite brown in appearance, then you probably had a lot of Pd in there, if you dilute it you will see a rich yellow color. Now be careful here, Pd ion in solution has a very intense yellow coloration, so intense that it looks brown when concentrated. Ferric nitrate (iron III) can also have a yellow color in acid solution, but it's kind of bland. The best way to know the difference is to dissolve iron in nitric and dissolve Pd in nitric, one has a much richer yellow. Make sure you get a stannous test and look for the green Pd!
buffa1o1 said:
I washed & rinsed the recovered flakes/dust several times, then dissolved them in 4 parts muriatic acid and 1 part clorox, then
added 3 more parts water and percipitated the gold with SMB.
Excess water isn't usually a good thing, especially if you're going after an element that's just a trace. Keep your solutions concentrated. I'm assuming you had a positive gold stannous test (which can be difficult to ascertain with other things in there).
buffa1o1 said:
The solution at this point tested a rosey red color with the stannous test so I concentrated the solution to about 1/5 it's
original volume, tested with stannous and received the above pictured result.
Good, good! Concentrate it!
buffa1o1 said:
I then used 1/2 fl. oz. of the concentrated solution which I had dropped the gold from to conduct Hoke's platinum experiment
by adding heat (not mentioned in Hoke's experiment) and Ammonium Choride to percipitate about a heaping tablespoon of
the orange powder in the photo.
I dried the orange powder then sintered it on porcelain down to a slightly darkish grey powder with a slight hint of red hues,
it produced a loose but spongy powder. (the color of the sintered material is much more grey under good light than it shows in
the picture and does not match the color of the actual sintered powder very well but the color of the swatch and the
percipitated orange powder are a close color match)
Ok, you're doing this mostly right. After the heat though, you should cool it in an ice bath. Once your Pt has precipitated, filter it and rinse with ice cold saturated ammonium chloride solution. Now look at the filtrate (the liquid, not the precipitate) and see if it has any residual yellow color to it; if it is faint, then there's probably not that much Pt left in it, but you can do a stannous test against standard solutions of known concentration to get a good guestimate. If you're going for broke and don't care about the other metals beside Pt in the filtrate, you can get all of the last Pt group out of that solution by cementing with zinc and boiling that reduction in HCl to remove excess zinc. That powder can then be tossed into the next batch you refine.
Your orange powder should've done some weird things when you heated it, like turning dark and releasing lots of white smoke (ammonium chloride). You have to go low and slow with the heat or you can gas phase transport your money into thin air. IF there's a slight reddish hint left to your reduced platinum sponge, then you need to heat it again til it's gone, or boil in nitric and see if there's any color change. If there is, then you didn't eliminate all of the base metals. This material, properly reduced should be a heavy gray sponge.
buffa1o1 said:
I then dissolved a small amount of the grey sponge in an AR solution made from Sodium Nitrate and Muriatic acid, I heated it
to dissolve the grey sponge into solution and then used the stannous chloride test and it showed a light rosey red colored
stain (not pictured).
This was good, but you should've first boiled in hydrochloric (muriatic acid)
or in nitric to remove any crap that might have been dragged down. It's an additional purification step. Then you give it the 'ol aqua regia treatment and get a nice dark red solution.
buffa1o1 said:
I could use some help on this because I have a fairly large batch of the concentrated solution (about 80 fl. oz). I think the
solution I used in the experiment may still contain a little Gold, some Platinum group metals and I do not want to miss any values.
80 fluid ounces of this? Someone will be having a very nice Christmas! Just make sure you know what concentrated means when you're dealing with the PGMs, to me, conc. is over 10 troy ounces per liter of solution.
All in all, not a bad shot at this.
buffa1o1 said:
Note: The enlarged text is not an attempt to shout, It is just easier to read for some of us
<b>Any comments or advise is appreciated.</b>
As for the font, no big deal!
The only thing that bugged me is percipitated. It's
precipitated. I swear I'm not a grammar Nazi.
Again, welcome to the forum. I hope I helped you out. Keep the pictures coming and we'll be sure to make sure you're doing this right.
So far, it seems like you've got most of it quite well.
Happy Holidays,
Lou
EDIT: Just curious, but did you use more ammonium chloride than you were supposed to? The precipitate looks O.K color wise, but not physically: I've seen some people here use too much ammonium chloride and get different crystals.
