I would rinse everything down with 2% sodium sulfite solution acidulated to a pH of 4 while wearing a full face respirator and the gear that 4metals has previously spoken of--be sure to ditch your gloves and wipes into a container. Do that until q-tip swabs will no longer test even the faintest orange and a swab with formic acid doesn't go black/grey with dipped into dilute caustic solution.
palladium reduction
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Geo
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I have run out of time. I have to clean it up tonight as rain comes into the forecast for tomorrow night. It's too hot to work outside in the daytime. Especially with respirator, paint suit and gloves.
Geo
Well-known member
I have SMB but no sodium sulfite. Can I heat the SMB to obtain sodium sulfite or can I just use the SMB? I have a pen style PH meter so adjusting the PH is no problem.
Geo
Well-known member
I have cleaned up the mess and captured as much of the metal salts as I could. I estimate that I was able to recover three quarters of what was in the beaker (unscientifically) by way of the color of the solution and the amount of water and acid needed to dissolve all the salts. I ordered some zinc metal powder and dropped all the metal with zinc. I don't think I will try to refine PGM's to pure metal again. I believe that getting it to the level of the starting solution and dropping with zinc will be good enough for me. I am now at the point where I will be trying to melt the cemented powder in a few days. I have oxy/acetylene and oxy/propane. I'm sure the the oxy/acetylene will melt the powder but I am concerned that the pressure needed for that much heat will blow the powder out of the dish. I have plenty of clean cemented silver but would like to melt the PGM's directly without the silver as a collector. I have a new fused silica melting crucible for torch melting. Dark welding goggles should work for the melt. I'm going to try and melt a small BB first to see how it's going to react to the torch. Has anyone else ever melted PGM's with a torch before and if yes, how did it work out?
Finely divided metal powder can be melted with a hand torch. It is an art that comes with practice! It is soooooo easy to blow more powder out of the dish than you melt. (I wonder how I know this!!! :mrgreen: )
One thing that makes it easier is using a high back crucible, the flame is directed to swirl down and circulate in the dish, which tends to hold the heat longer and make it easier to keep the unmelted metal powder in the dish.
given the choices you listed for melting gas, I would choose the oxy/propane torch to melt the Palladium. Since Palladium has a tendency to absorb oxygen when molten and expel it on cooling making for an ugly button. (Definitely not worthy of a gallery photo!) To avoid this when the Palladium is molten and has formed into a button, cut back on the oxygen in the torch and slowly while rotating the flame allow the button to cool slowly in a reducing flame. This will allow it to give up the oxygen and cool slower resulting in a nicer surface finish.
One thing that makes it easier is using a high back crucible, the flame is directed to swirl down and circulate in the dish, which tends to hold the heat longer and make it easier to keep the unmelted metal powder in the dish.
given the choices you listed for melting gas, I would choose the oxy/propane torch to melt the Palladium. Since Palladium has a tendency to absorb oxygen when molten and expel it on cooling making for an ugly button. (Definitely not worthy of a gallery photo!) To avoid this when the Palladium is molten and has formed into a button, cut back on the oxygen in the torch and slowly while rotating the flame allow the button to cool slowly in a reducing flame. This will allow it to give up the oxygen and cool slower resulting in a nicer surface finish.
Geo
Well-known member
So it would be this one from their website?
http://www.crhill.com/wesgoplatinummeltingcrucible.aspx
http://www.crhill.com/wesgoplatinummeltingcrucible.aspx
Yep! They're like 14 bucks each in quantity from Wesgo. They last about 50 melts but I've done my melt loss on 1000s of ounces of Pd by weighing sponge and melting it in those high back dishes. I use an oxyhydrogen torch.
4metals is right...lots of practice required to do it right.
Start with a small slightly lean flame and work it over the heap of black powder until a sintered crust forms. Then increase the heat and move in a spiral from the outside in with the torch flame at an appropriate angle.
Easier said than done.
4metals is right...lots of practice required to do it right.
Start with a small slightly lean flame and work it over the heap of black powder until a sintered crust forms. Then increase the heat and move in a spiral from the outside in with the torch flame at an appropriate angle.
Easier said than done.
Geo,
The picture on the site you linked is hard to be sure but they offer two types, you want the high back crucible. I think, and again it may be the angle of the photo, the one in the picture is not a high back, the picture I posted is what you want.
The high back crucibles look like the crucible was laid on its side in a miter saw and cut at a 45 degree angle. When you place the flame it should be directed off center and towards the high side aiming down into the crucible so the flame bounces off the high wall and spirals down. The flame will heat the powder and continue in a circular pattern until it contacts the high back wall again, apparently the height helps contain the powder.
Practice with gold powder or silver crystal before you move on to the Palladium.
I just went back to the website, the one selected in the link is the low form, if you select product options and click on high back you can see the difference.
The picture on the site you linked is hard to be sure but they offer two types, you want the high back crucible. I think, and again it may be the angle of the photo, the one in the picture is not a high back, the picture I posted is what you want.
The high back crucibles look like the crucible was laid on its side in a miter saw and cut at a 45 degree angle. When you place the flame it should be directed off center and towards the high side aiming down into the crucible so the flame bounces off the high wall and spirals down. The flame will heat the powder and continue in a circular pattern until it contacts the high back wall again, apparently the height helps contain the powder.
Practice with gold powder or silver crystal before you move on to the Palladium.
I just went back to the website, the one selected in the link is the low form, if you select product options and click on high back you can see the difference.
Geo
Well-known member
I have ordered one crucible to work with. I still have a couple of tons of old military boards that contains a lot of PGM's. One reason I haven't refined them already is because I was basically tossing the PGM's with my solid waste because I didn't know how to deal with it. I have sold PGM blacks but the price I received barely made it worth the chemicals and no where near the worth of my good health. I really appreciate all the help guys. I may play around with this one crucible but will most likely melt this batch using silver just to finish it up. I will keep a few grams to practice with when the crucible gets here. I will post a picture of what ever I get out of it.
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Geo said:
This stuff is literal academic "gold!" I'm literally doing the same process. I used zinc to precipitate pd from a saturated and clean solution after the gold was dropped using smb. Followed the steps outlined in this forum after many searches and much reading. Took two days of slowly adding zinc, but I finally got a successful drop that didn't boil over or spill. There is a thick layer of black powder settled on the bottom of my beaker and so much fine particulates still in suspension that the solution looks black. Going to start filtering soon. I'm not interested or comfortable with refining the pd further as my experience with pgms is limited at best. Thanks everyone for going ahead of me so I could learn how to do this safely and correctly. Much love!
Geo
Well-known member
The black cement is deceptively voluminous. A large volume of fluffy black powder will dry to hardly nothing.
