# Ruthenium melting question



## mnap89 (Apr 3, 2016)

Hi everyone

I am a goldsmith and I need to make platinum alloy - I have choosen 95Pt5Ru alloy which would suit my needs.
Making an alloy isnt a problem but I have read somewhere that Ruthenium oxidises at +800C. And I have found that there are two main oxides II and IV from which IV is very toxic.
But I am also confused because I have seens video where someone was testing chemical resisstance of pure Ruthenium and it reacted only to bleach which oxidised it into ruthenium Oxide IV.

All alloy suppliers doesnt say anything about ruthenium oxide hazards when melting this alloy. I have found only one supplier which mention thet you should do it under fume hood but he does say why.

*I just want to know is it safe to melt it or should I use caution?*

And I cant get alloy form the supplier because in my country no one is offering that alloy - unless you buy whole lot. And I like to do it my self.


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## Lou (Apr 3, 2016)

It is indeed dangerous to melt ruthenium by torch and it will make dangerous fumes even in alloy form if a greatly oxidizing flame is used.

To handle PGMs you should consider investing in a small vacuum induction furnace


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## mnap89 (Apr 4, 2016)

Yes, vacuum induction casting machines are superb tools. But like all great machines - they cost a small fortune, which I dont have 

Thanks, Lou - point taken. I will consider making it under na fumehood and with respirator. Any ideas what type od filter should I use for that kind of stuff? Will carbon work for this?

Also I will think about different alloy. But there are not many to choose from - Cobalt is the heardest one but It can not be torch melted, Ruthenium - toxic fumes, copper - toxic fumes. The safes seems to be 95 and 90 platinum - idirium but 95 is too soft, 90 seems har, doesnt oxidise at all but the biggest drawback is iridium price. Other alloys with silver, palladium and what not are no interest for me...


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## nickvc (Apr 4, 2016)

Many years ago when I worked for JM we had an export department, JM are now Cookson you could try getting in touch with them and see if they can ship the metal you need, as I said I know they used to but it was some years ago, and it might be safer and cheaper than trying to make your own alloy.
Again from memory many Pt alloys contain cobalt which is why they are magnetic.


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## Lino1406 (Apr 8, 2016)

Iridium price an issue, while platinum consists 90-95%?


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## mnap89 (Apr 9, 2016)

Lino1406 said:


> Iridium price an issue, while platinum consists 90-95%?



For customer - it is. Alloys made with copper or silver are much cheaper than iridium, ruthenium, gold or palladium ones.


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## alpine1967 (Jul 14, 2016)

Did you find a method to make your alloy? I have access to an inert atmosphere arc-melting furnace. Are you interested?
Tom (USA)


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## zachy (Sep 23, 2016)

basically the most serious in the casting platinum problem is the high working temperatures ecima 1,800 degrees, to achieve good fluidity, besides the investimento should be special for platinum, basically alloys best known are Pt-Co and Pt-Ir .


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## Rougemillenial (Dec 20, 2016)

mnap89 said:


> Hi everyone
> 
> I am a goldsmith and I need to make platinum alloy - I have choosen 95Pt5Ru alloy which would suit my needs.
> Making an alloy isnt a problem but I have read somewhere that Ruthenium oxidises at +800C. And I have found that there are two main oxides II and IV from which IV is very toxic.
> ...


thekingofrandom made an arc furnace a while back which would get more than hot enough to do the melt. if you have some old lantern batteries, do the first firing inside your reaction chamber with the ruthenium. the wax burn off will quickly get rid of the oxygen. also I've tried to use a torch before and i can pretty much guarantee you that it won't melt let alone be liquid enough to pour. you need an induction or inert atmosphere arc furnace to do the melt.


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## Lou (Dec 20, 2016)

952PtbalRu can be torch melted with neutral O2/H2 flame. Using a carbon arc can ruin the metal. I actually made a same KingofRandom design and used a TIG welder as powers source. The graphite electrodes where much higher quality than lantern battery rods. The Pt got stuck all over them. I think the only way to do arc melting of Pt is in water cooled hearth with a tungsten electrode.


I didn't see that the OP is in Poland. He should just go visit Marcin at Argenta and use their furnace to alloy his metal.


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## Iridium chaser (Dec 25, 2018)

Well,believe it or not but I did smelt pure ruthenium with the oxy/mapp torch and I did it exactly yesterday!So obviously the quantity was not big by any means-at the beginning I measured exactly 1.020 grams of ruthenium sintered pieces-just three of them were there and also it was a huge pain in..Well it was like really ridiculously tedious and odious:4 oxygen tanks(those from bernzomatic-little red ones;41 grams of pure oxygen each),were one after another spent on the task but anyway it was for the bet and I got it melted myself which has given me somewhat proud of myself..
As for ruthenium I ended up with a bead that was weighing 1.004 grams with a layer of black to purple dioxide and after removing the layer of dioxide the final weight is measured to be 0.994 grams so as the simple doctor's paper mask soaked in the very dilute sodium hydroxide solution holds the vapour of ruthenium tetraoxide very good-so from volatilized 0.016 grams of it there was zero harm whatsoever..Although there are some really ridiculous facts about it:first of all the sintered ruthenium is really a nightmare to work with-I noticed that it was far easier to smelt a gram of iridium powder by the same torch regardless of it's higher melting point..A-secondly,I was really surprised to see that the piece of zirconium dioxide which was underneath it had a bit melted and I had to knock the ruthenium ball out of it and also to crack the glassy crust from it's surface and so that is remarkable because zirconia melts at more than 2700°C and actually it's melting point is 380°C above the ruthenium melting point..And since ruthenium is the second hardest to machine of all PGMs and one of the toughest among all elements-1 gram iridium got melted on a single oxygen tank and with zero loss while ruthenium required four of them!


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## Platdigger (Dec 25, 2018)

When you say "smelt" do you mean melt?


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## Iridium chaser (Jan 7, 2019)

I mean basically melting either several chunks or/and sponge into a single button.As for me I consider the form of pure metallic beads or buttons as my final product of refining actions..Anyway it's a challenge but it is obviously becoming vastly easier when you get enough equipment for that.For example a 150 l/h HHO torch costing 550 dollars Canadian is actually more than enough to easily melt anything except osmium metal(unless you have a proper flux):I myself had melted rhenium metal with it so quite a good variant..


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