Poor man's Pfaudlers?

[HAuCl4]

http://www.amazon.com/FlavorStone-Blue-Sapphire-Essential-Cookware/dp/B008G0QB18/ref=cm_cr_pr_product_top/182-4403608-9689752

Anyone used them for A.R. refining yet?. The coating is sapphire. Non-scratchable compared to teflon. :shock:

 

[goldsilverpro]

It says here the inner coating is ceramic or Marble. Pan is aluminum. I sure don't think I would use AR in those.

http://www.alibaba.com/product-gs/961536946/9_5_Blue_Sapphire_Essential_Cookware.html

 

[Harold_V]

http://www.amazon.com/FlavorStone-Blue-Sapphire-Essential-Cookware/dp/B008G0QB18/ref=cm_cr_pr_product_top/182-4403608-9689752

Anyone used them for A.R. refining yet?. The coating is sapphire. Non-scratchable compared to teflon. :shock:

Heh! Sapphire? Corundum?
It has another name. It's called anodizing (and dyed blue). Same thing--and VERY thin--if there's a thousandth of an inch of anodize present, I'd be surprised. The slightest scratch and you'd have instant destruction unless they were used only with nitric acid.

Harold

 

[HAuCl4]

It can crack if you hit it hard or something, and sure the acid will get through and damage the vessel. Kind of expendable though.

But you can't scratch it, unless you purposedly use a diamond or something harder like boron nitride... It's harder than quartz. :shock:

 

[goldsilverpro]

http://www.amazon.com/FlavorStone-Blue-Sapphire-Essential-Cookware/dp/B008G0QB18/ref=cm_cr_pr_product_top/182-4403608-9689752

Anyone used them for A.R. refining yet?. The coating is sapphire. Non-scratchable compared to teflon. :shock:

Heh! Sapphire? Corundum?
It has another name. It's called anodizing (and dyed blue). Same thing--and VERY thin--if there's a thousandth of an inch of anodize present, I'd be surprised. The slightest scratch and you'd have instant destruction unless they were used only with nitric acid.

Harold

I would bet that Harold is right. Anodized Al is a coating of aluminum oxide, which also makes up sapphire and carborundum. Alumina is a ceramic composed of aluminum oxide. The use of these terms is an advertising ploy to make people think of toughness. In reality, it's just anodized aluminum.

 

[Harold_V]

I would bet that Harold is right. Anodized Al is a coating of aluminum oxide, which also makes up sapphire and carborundum.

Not carborundum, which is made of silicon and carbon, but corundum, which is primarily aluminum oxide.
Those two names are a source of considerable confusion.

Harold

 

[goldsilverpro]

You're right, of course, Harold. My error.

 

[Geo]

The question that comes to my mind would be, why would you want to? Of the set, the large pot is the only one tall enough to use without worrying about a boil over. The set list for $109 on their website. That's plenty enough to buy a large glass vessel to process in.

 

[Harold_V]

The question that comes to my mind would be, why would you want to? Of the set, the large pot is the only one tall enough to use without worrying about a boil over. The set list for $109 on their website. That's plenty enough to buy a large glass vessel to process in.

Yep! My thoughts, exactly.
I tend to discourage the use of metallic vessels of pretty much any description (aside from the incineration process), although one might get by nicely with a 300 series digestion vessel, assuming its use was limited to nitric acid.

Harold

 

[Lou]

Hey Harold, if you've got the coin, nothing beats tantalum cladding for acid-digestion reactions, though hydrogen embrittlement can be a problem at higher temps.

 

[moose7802]

I want one now! But it doesn't seem like this will be cost effective for the at home refiner any time soon.

http://tantaline.de/Tantalum-Coatings-840.aspx

Tyler

 

[Lou]

They can't yet do large apparatus. Even then, it's not much cheaper.

 

[Harold_V]

Hey Harold, if you've got the coin, nothing beats tantalum cladding for acid-digestion reactions, though hydrogen embrittlement can be a problem at higher temps.

Interesting! Having no experience with tantalum, that's news to me, for which I thank you.
In regards to hydrogen embrittlement, if the base material isn't heat treated, pretty good chance hydrogen wouldn't be much of an issue, unless there's something I don't understand.

Considering most plating isn't very thick, and the vessels used in refining are subject to some abrasion (especially if one processes polishing wastes from the jeweler's bench), seems like it wouldn't be all that hard to wear through. The beakers I used for that purpose had a relatively short lifespan.

Are you familiar enough with that which is offered (in regards to the applied tantalum) to describe how the tantalum is applied to the base metal?

Funny thing. Even when one's objective in being here is not to learn (mine is just that--I am no longer interested in refining), there sure is a lot that can be absorbed.

Harold

 

[etack]

If anyone is interested in this I have several pieces of Ta scrap sheets they would make great anodes too.

Eric

 

[Lou]

I can vouch that Eric knows his stuff on tantalum.

Tantalum clad is different than the tantaline process, which I think is probably cheaper as it uses a thinner layer but actually diffuses it into the metal based on the micrographs they have on their site.

If I had to guess, based on me having messed with tantalum pentachloride and other volatile refractory metal halides years ago and seeing the phenomena occur with SS316 pipes in my tube furnace, this is what I think they're doing:

Into a vacuum chamber, the operator would put in a stainless alloy material, like bolts, reactors, impellers, etc. Then it's evacuated, temperature brought up to 800-900C to increase diffusion and TaCl5 (immediately forms a gas) is introduced and is then reduced onto the surface. It then alloys itself at the interface between the different metals, making a cohesive cladding that is a couple thousands of an inch thick. If not all of the part is desired to be clad, then it can be masked with copper foil.

Agreed, super abrasive materials shouldn't be used in such reactors, but for high noble alloy content material, they make great digesters.

I think they have good tech, and I'll probably want one when they make them bigger.

 

[Harold_V]

Thanks, Lou. All new to me, and quite interesting.

Harold