# palladium reduction



## Geo (Jun 27, 2016)

I am in the middle of reducing the volume of palladium chloride I have stored. I have been reducing the solution by evaporation until it changes from red to almost black. I have about 500mL of this black palladium chloride. I am just now getting some NO2 formed in the evaporation. My problem is, I am getting some blood red crystals formed in the solution. Have I evaporated the solution too far? It is a nice clean solution with little contamination. These red crystals are slow to dissolve in water and the solution is bright red once dissolved. 

I do understand the dangers of concentrated palladium chloride because I have been studying on it for over a year and decided to try and precipitate what I have stored and calcine it. I will be using a chlorine generator to bubble chlorine gas through the solution. When do I know it is evaporated low enough? If I am getting solid crystals of Pd salt, it should be ready or no?


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## nickvc (Jun 28, 2016)

Geoff never done this but I'd say if your getting crystals you have gone too far, the material needs to be in solution to precipitate it, I know you know the dangers but be ultra careful with that solution and any gases or salts from it.
We're it me I would simply cement it out that way you have no salts to worry about especially if it is just a Pd solution with no other values, then rinse and melt the Pd blacks, much simpler and safer I'm my opinion.
If your doing this out of scientific interest then ignore my opinion and be safe.
Further opinion ask Lou :idea:


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## 4metals (Jun 28, 2016)

Dilute it until the solution has no more crystals and filter out any PdO which may be in there, that has to be roasted and re-dissolved.

De nox all solutions.

Then add an equal volume of saturated ammonium chloride to your starting liquor followed by sodium chlorate to drop your Palladium as Palladium(II) ammonium chloride. The salt is hygroscopic and the dry (dessicated) salt weight multiplied by .37431 will tell you how much Palladium is present. 

I often will dry and weigh the salt to settle an individual processing lot and accumulate enough salts before reduction to metal.


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## nickvc (Jun 28, 2016)

Or 4metals


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## Geo (Jun 28, 2016)

Thank you Nick and 4metals. 
I have the chemicals needed. I evaporated the solution in a fume hood and handle everything with thick rubber gloves. I wash my gloved hands in a basin before taking them off. I wear eye protection and an apron. I am trying to be as careful as I can be. 
So dilute until the crystals dissolve and filter. Add an equal volume of saturated solution of ammonium chloride and then add sodium chlorate to drop the palladium(II) ammonium chloride. 
This is the first time I am trying this process. There is a lot of Pd in the material I deal with. I want to get the best price I can get for it.

Thanks again for the information.


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## nickvc (Jun 28, 2016)

Geoff I doubt whichever route you take the payout will be any different percentage wise, I'd stick to cementation and a simplish melt, if you need an assay on the bar my mates in the UK will do it for about $20 or less and they are quick.


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## 4metals (Jun 28, 2016)

There is always a chance you may have Platinum in there as well, one way to get it is to leave the solution sit after the ammonium chloride addition and it will drop out of solution. If it is not much it may take overnight. Then filter and collect the Platinum as Ammonium chloroplatinate. 

No sense giving away your Platinum for Palladium prices!


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## Geo (Jun 28, 2016)

So as soon as I added the ammonium chloride solution, this yellow precipitate fell out of solution. I am assuming it is platinum. I would have argued that platinum is not used in electronics, I guess I would have been wrong. Thanks again for the information.


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## 4metals (Jun 28, 2016)

Considering the difference in price between Platinum and Palladium, I would consider that color Happy Yellow!

The yellow powder, dried and weighed, is 43.95% Pt by weight. 
Pt factor as ammonium chloroplatinate .4395 (Platinum ammonium chloride) 

So considering the difference in percentage of metal per ounce of salt and the price difference, happy yellow is a good description.


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## Geo (Jun 29, 2016)

Okay, complete failure. After filtering the yellow salt out of solution, I placed the 1000 mL beaker with roughly 600 mL of solution in my catch pan and started adding sodium chlorate. There was a nice brick red solid precipitating out. I waited a few minutes and added some more. About a half teaspoon each time. I waited for another five minutes and added some more. I noticed a blocky looking salt forming on the bottom of the beaker. After some time, I added the last of what I was going to add and closed everything up and went inside. I am still shaking thinking about it. I was getting ready for bed and I heard a pop. Loud pop from outside. I was afraid it had something to do with the beaker and the strange salt. I got dressed and went out slowly, not know if a cloud of chlorine gas was waiting. Nope, no cloud. I walked out to the fume hood and there was the Pd solution everywhere. Dripping from everything in the fume hood. The beaker had exploded. The catch pan had a little in it but the majority was everywhere else. And I had been standing right in front of it not less than fifteen minutes before. No heat, no flame. I just closed everything back up and decided that I had had enough excitement for today and I will clean it up tomorrow. Win some, lose some. At least it was my own material.


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## nickvc (Jun 29, 2016)

Geoff do you think it was an exothermic reaction?
Whatever the cause we need to find out as that could have been so much worse and I'd hate anyone following the thread to have the same thing happen but be standing in front of the beaker!


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## Barren Realms 007 (Jun 29, 2016)

It is recomended to the reduction in a cold solution.


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## 4metals (Jun 29, 2016)

OK let's get back to basics and see what happened. 

How did you generate this concentrate, you said you evaporated solution down to make a concentrate. What solution and how was it generated? Was it nitric to start with or aqua regia? 

I did make some assumptions that apparently I shouldn't have. But let's start at the beginning.


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## Geo (Jun 29, 2016)

It started out as AR solution solutions from gold refining. As I would drop the gold, I would collect the spent solutions that tested positive for palladium. I cemented the blacks from these solutions after I have accumulated enough using copper while heated. When I had enough blacks, I would dissolve the powder in AR and drop the gold and store the red solution. At the beginning of this thread, I said that the evaporation was at the point where NO2 was being generated and that red crystals were forming. Would the presence of nitric acid in the solution have caused the explosion?


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## Geo (Jun 29, 2016)

I checked the beaker before I went inside and it was cool to the touch. I was concerned because the reaction was getting strong. There was brick red precipitate both in the bottom of the beaker and floating on top of the solution. I noticed what looked like large yellow and transparent crystals forming at the bottom of the beaker below the red precipitate. My last thought about it was how to separate the two different kinds of crystals.


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## 4metals (Jun 29, 2016)

So the cemented values were digested in aqua regia, filtered and concentrated. 

I am a little confused about volumes. You started with 500 ml. You added water to dissolve any crystals but no mention of de-noxing, no sulfamic additions I assume. You should always de nox all solutions before dropping the metals, if you were blowing red fumes, you still had active nitric acid. Sometimes dilution is sufficient but it's a crapshoot; de-noxing is always best. 

So after diluting the crystal you had what, 600 to 700 ml? Then you should have added an equal volume of saturated ammonium chloride. That would have put you at 1200 to 1400 ml. In the picture you posted of the Platinum drop after the ammonium chloride additions the volume is at 600 ml. 

When you add the sodium chlorate to the room temperature solution the palladium drops like a reddish color fine sand, that is what you experienced as well. What I believe the problem was you had free nitric in solution and the solution did not benefit from the 50% dilution with saturated ammonium chloride (did you add it as a powder?) You had a concentrated solution containing free nitric acid and you added a powerful oxidizer, and likely over added. A whole lot of chemistry going on in a small concentrated space! 

With chemistry experience is your best teacher, when you see the reaction you are looking for (dropping red sand) and then start seeing a different reaction (the blocky looking salt) you should immediately stop adding the reagent as you have passed the point where the additions are doing what you wanted them to do. 

I have never seen sodium chlorate react as you describe but I always work with de-noxed solutions that has been diluted 50% with the solution of ammonium chloride.


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## Geo (Jun 29, 2016)

By the time I had added the ammonium chloride solution, the original solution was at 300 mL. I doubled the volume with the ammonium chloride which brought the volume to 600 mL. That is the solution in the pictures. I did not dilute the solution any farther. It did have nitric acid in solution because it was being evolved when I turned off the heat and let it cool at 300 mL. I didn't denoxx as I didn't know that I needed to. It's a hard lesson to learn. When I first started refining gold, I lost quite a bit to inexperience. I imagine this would be no different..


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## UncleBenBen (Jun 29, 2016)

Well I hate that you lost your palladium, Geo. But I sure am glad you weren't in front that beaker when it detonated!


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## 4metals (Jun 29, 2016)

When de noxing solutions by the classical 3 times evaporation process, you evaporate the solution down to a syrup with small sulfuric additions and re-hydrate with HCl and again reduce to a syrup. When you get down to a thick syrup you see the nitric coming off as a red fume, by the third time all of the nitric should be gone. 

Very time consuming which is why I prefer sulfamic acid. 

I learned something from this as well, I should always list *all* of the steps and *never* assume anything.


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## Geo (Jun 29, 2016)

I had thought about using sulfamic acid but didn't because I know that ionized metals can be very reactive. Now I know that it can be used in this process. 
Okay, back to the business at hand. Toxic cleanup. Face shield, apron, rubber gloves (elbow length). I will use paper towels to wipe as much of the red salt from the inside of the fume hood. Gather all the items in the hood and wipe them down. These towels will be collected in a bag for incineration. Any glass will be emptied into the stock pot and washed in dilute HCl followed by a water rinse and then soap wash. The inside of the fume hood will be wiped down with dilute HCl and soap wash. The hot plate will be soap washed and the wash water neutralized. 
I think I can gather up a large amount of what was in the beaker. I need to pour up what's in the catch pan to see how much of the 600 mL of solution is left. It was precipitating red salt quickly so the solution may not have anything left in it.


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## FrugalRefiner (Jun 29, 2016)

From Hoke, page 55:


> (5) EVAPORATING OFF THE EXCESS NITRIC ACID
> Here again the steam bath is advised, especially for large quan-
> tities of material. Sometimes this evaporation may go too far, and
> brown metallic gold will bake out onto the dish. You can easily
> ...


While this process was for putting gold back into solution if you evaporate too far, the underlined portion may be the key. 

Interesting that I just read in a different thread that a member felt Hoke was antiquated.

Dave


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## FrugalRefiner (Jun 29, 2016)

And from page 108 where she describes dropping the palladium:


> Warm the mixture gently, and add a single crystal of sodium
> chlorate. Or, dissolve a pennyweight of chlorate in a little warm
> water, and add a drop at a time. There will be considerable fizzing,
> and as it subsides, add another small crystal or another drop. The
> ...


I believe you said the solution was cool. I suspect that was the problem.

Dave


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## Geo (Jun 29, 2016)

I was just coming in to post that I figured out what happened. I'm glad that Dave posted before I did. I was finding small pieces of white glass. At first I was puzzled thinking it was a white crystal from the reaction. The pieces was very small to slivers a quarter of an inch long. I about fell over when I realized that I had set one of my small china saucer plate on top of the beaker when I went inside. I had forgotten that I had set it up there. It is habit to cover beakers with solution in them. I noticed that the explosion seemed to be in one direction with a spread of about 45° from the beaker towards the back of the fume hood. I'm assuming that is where the pour spout was pointed. When the fuel/air mixture reached a certain point, it detonated in the space between the solution and the plate. The plate disintegrated and the beaker came apart leaving the bottom intact. There was no glass outside the fume hood.


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## FrugalRefiner (Jun 29, 2016)

I just looked through some more of Hoke's references to chlorate, and she always mentioned working with hot to near boiling solutions.

Glad I was able to help sort it out, and very glad you weren't hurt. As we often say, and you well know, no amount of precious metals is worth your health.

Dave


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## 4metals (Jun 29, 2016)

> ionized metals can be very reactive



I'm really not sure where you got this statement from, because it really depends. When working with relatively clean solutions, as you were because they were dissolved from cemented values, the target metals are there just waiting for the right reaction. When you introduce a lot of extra metals and chemicals in solution it gets complicated. But just like in life, you can have too much of a good thing and screw things up. 

The Platinum and Palladium that have dissolved in acid have already reacted and are now dissolved in solution as ions. The reactivity came when the acids dissolved the metals and once in solution they're relatively happy. As long as the new chemistry you are introducing isn't going to cause them to displace the ion they are currently in a dance with for the new ion, they will remain content. 

So the sulfamic you add will prefer to react with any free nitric in solution and not be causing any problems with any of the other ion pairs as long as you don't add too much and upset the equilibrium. 

The ammonium chloride will upset the platinum in solutions equilibrium and cause the platinic acid to drop out as a salt which is ammonium chloroplatinate. But it is not a violent reaction. The ammonium ion wants to grab on to that sexy looking hexachloroplatinate so it just bounces a relatively easy to replace hydrogen out and jumps in there. 

The Palladium is in solution from an aqua regia dissolve as a hydrated chloride and the sodium chlorate wants that chlorine bad so it grabs it and poor Miss Palladium is quickly (sometimes not so quickly if it's dilute) available for some of that excess ammonium chloride in solution to form Palladium Ammonium Chloride which is not soluble and drops out. Also a simple displacement reaction. 

What I think happened is the free nitric got into a spat with the ammonium ion and formed some ammonium nitrate. That is what caused the excitement. It is hard to say if this would have happened if the solutions were not as concentrated as they were but the combination of the ammonium and free nitric did you in and the strong oxidizer provided by sodium chlorate put it over the top. (literally)


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## 4metals (Jun 29, 2016)

Ammen also speaks about dropping the Palladium from hot solutions. But he also likes to drop the Platinum from warmed solutions as well. I have always had success with cold acids. Geo also had results from the room temperature reaction. I think the heat around sodium chlorate is more of a hazard than a benefit.


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## FrugalRefiner (Jun 29, 2016)

Geo said:


> Okay, back to the business at hand. Toxic cleanup. Face shield, apron, rubber gloves (elbow length). I will use paper towels to wipe as much of the red salt from the inside of the fume hood. Gather all the items in the hood and wipe them down. These towels will be collected in a bag for incineration.


I'm not so sure incineration is in your best interest. When PGM salts are calcined, the heating needs to be carefully controlled, otherwise some of your palladium could be volatilized and go up in smoke. If it were mine, I would probably try putting the paper towels in a beaker and using several changes of solution (water, HCl?) to rinse out as much as possible. When you feel you've rinsed them as well as possible, you could incinerate to try to capture anything that stubbornly clings to the towels. This is all a guess on my part, so I hope someone with more experience will address this part of the recovery.

Dave


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## Geo (Jun 29, 2016)

I could dissolve the paper with sulfuric acid.


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## 4metals (Jun 29, 2016)

Or you could pyrolyze it under 700 degrees. I think you are right about all of the Pd being out of solution when it popped but even the salt needs to be calcined to prevent losses.


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## FrugalRefiner (Jun 29, 2016)

I was assuming that what he wipes up with the towels will be a combination of the (potentially) barren solution and the precipitated salt.

Dave


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## Geo (Jun 29, 2016)

My electric burner is a little over 500°F. I can use an iron pot with a lid or a pyroceram casserole with a lid.


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## 4metals (Jun 29, 2016)

If you get one of these;

http://www.agrisupply.com/carolina-cooker-9-qt-preseasoned-dutch-oven/p/90677/ 

and drill a hole in the center you can tap, screw in a piece of 1/2" threaded black iron pipe sticking into the pot but short enough that you can put the lid on and it will still fit tight. This will cause the gasses to pass out the bottom where they will be burned because you are heating on one of these;

http://www.agrisupply.com/carolina-cooker-stand-and-burner/p/49469/

You have to monitor the temperature with one of these:

http://www.harborfreight.com/non-contact-infrared-thermometer-with-laser-targeting-69465.html

it measures up to 950 F so it will work. 

Think of all the stuff you can pyrolyze now!!!!!!!


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## Geo (Jun 29, 2016)

I already have all of that so that looks like what I will do, thanks.


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## 4metals (Jun 29, 2016)

That Agri supply looks like a great store to walk around in, we Yank's don't get anything like that!


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## Lou (Jun 30, 2016)

Please no weighing of dried platinum salts if at all humanly possible to avoid it.

Also, please keep in mind the dangers of NCl3 formation (more so than even ClO2 formation in a closed space)--both explode spontaneously. Chilled solutions mitigate NCl3 formation. 

Geo had very little Pd in solution relative to Pt. He did not affect a more complete precipitation because his Pt was not all Pt(IV) but some was Pt(II) from the gold reduction process. 

Also, such quantities of ammonium chloride are completely unnecessary.

In the future, use potassium chloride for a safer experience if you see it necessary to risk contaminating your work space over maybe 5 g of platinum and a gram or less of palladium.


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## 4metals (Jul 1, 2016)

This is an good informative thread so I wanted to explain some of what I said and what Lou added in a little more detail so there is no confusion. And, as always, discussion is good. 

Years ago, like 30, I had an excellent relationship with a gentleman who was the head chemist for a major dental alloy refiner. He told me that since most refiners were a bit under equipped on the analytical end, he had to come up with a methodology that would work with dilute as well as concentrated solutions. Ironically small refiners have the same issues today and this would apply to our members as well. He called his method bulletproof because it would yield the highest yields regardless of concentrations in solution. 

Some of his methods are because of what Lou mentioned in his post above. 



> He did not affect a more complete precipitation because his Pt was not all Pt(IV) but some was Pt(II) from the gold reduction process.



First and foremost this method recommends dropping the gold from the aqua regia dissolve first, and any reducing agent the refiner was familiar with could be used, because all they were dropping from this acid was gold. 

Once the gold was dropped, the solution was cemented on slabs of copper. This was done for a few reasons, one was to allow the refiner to work with a smaller quantity of acid, and the second was to drop any remaining traces of gold with ferrous sulfate. 

Back when I was told this method, the nitric was removed by the classic 3 times evaporation procedure. Urea was never used because platinum and palladium have a definite ability to form nitrogen compounds; which will affect recovery. Since then, the use of sulfamic acid for de noxing solutions has replaced the need for the lengthy classic evaporation method. 

Another benefit of cementing the values allowed the small refiner to get some idea as to how much metal they were looking at. The cemented values were roasted (which also serves to eliminate any PdO which is insoluble in aqua regia) and weighed. 

As Lou said, the quantity of Ammonium chloride Geo added is un-necessary but in the bullet proof recipe that is what is called for. If a refiner is more analytical (my kind of refinery) the ammonium chloride (or potassium chloride) can be added at the rate of 0.6 grams per gram of expected platinum. However, an excess doesn’t hurt. 

The roasted powders are digested in aqua regia taking care to use as little nitric acid as possible. The acid is filtered and de noxed, and the volume of the solution is noted. Next the gold is dropped with ferrous sulfate. Since this powder should have very little gold, it is dropped from the solution while it is as concentrated as possible. 

Now the gold is filtered out and the solution is diluted with 3 times the original volume of water. To this solution, a volume of saturated ammonium chloride (or potassium) is added equal to the starting volume before dilution. Now the platinum drop will be more complete. This was never done hot or even warm for that matter but heat shouldn’t hurt and may speed things up. 

The platinum salts are filtered out of the solution and the remaining solution is treated with powdered sodium chlorate by slowly sprinkling it over the surface. The red palladium salt will drop. 

I have always done this at ambient room temperature, as heat was not suggested in the instructions I received. In light of what Lou said about trichloroamine formation, I would say heat would benefit by allowing the gasses to escape the surface of the reaction much easier. 

The above method has proven to be effective for refiners without the ability to perform assays before processing so they could add closer to the stoichiometric quantities needed in these reactions. And while I have never experienced what Geo did, I would add some heat to the drops. It can’t hurt and especially for some refiner in an unheated barn up north it is better to be safe. 

Finally, Lou said;


> Please no weighing of dried platinum salts if at all humanly possible to avoid it



I can understand this and completely agree that handling platinum group metal salts can have terrible consequences and exposure of exposed skin or inhalation of the dust can result in Platinosis. https://en.wikipedia.org/wiki/Platinosis

But small refiners often pay on PGM's by out-turn, meaning they have to collect the salts and weigh them to quantify the yield for settlement purposes. For most small jobs, from jewelry lots or sweeps, or small dental lots, this is rarely in excess of a few ounces. 

I do prefer to weigh the dried salts on tared filters and collect them until there is sufficient quantity to reduce the salts to metal. I do this in a good hood (with good air flow in excess of 100 CFM/sq ft of hood opening) and I wear gloves, long rubber sleeves, an apron, and a respirator. I encourage those who do this to keep dedicated protective equipment for this work and wash it down after each use. 

Fortunately, most of our members are not needing to pay a customer for the PGM's as they are recovering stock pot values. These values can be reduced to metal by whatever method you choose without having to dry them out and can even be stored damp to accumulate until you have enough to process further.


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## Geo (Jul 1, 2016)

The carnage.


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## Platdigger (Jul 2, 2016)

Sorry for the mishap Geo. But it is interesting the amount of pt you found.


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## Barren Realms 007 (Jul 2, 2016)

Hey look at the bright side of things. You get to repeat the process but his time you will have a better understanding of what to expect. 8)


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## everydayisalesson (Jul 2, 2016)

So happy your OK bub. Looks as though you have quite a bit of material saved also( catch pans always good.) Take your clean up slow and meticulous and I would guess you should be OK.

Mike


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## Lou (Jul 2, 2016)

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.


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## Geo (Jul 2, 2016)

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.


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## Geo (Jul 2, 2016)

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.


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## Geo (Jul 15, 2016)

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?


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## 4metals (Jul 15, 2016)

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.


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## Geo (Jul 15, 2016)

So it would be this one from their website? 

http://www.crhill.com/wesgoplatinummeltingcrucible.aspx


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## Lou (Jul 16, 2016)

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.


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## 4metals (Jul 16, 2016)

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.


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## Geo (Jul 16, 2016)

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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## DylanDownright84 (Dec 2, 2020)

Geo said:


> 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.



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!


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## Geo (Dec 2, 2020)

The black cement is deceptively voluminous. A large volume of fluffy black powder will dry to hardly nothing.


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