# Alternate method for cat processing underway



## DNIndustry (Jun 10, 2009)

I have been playing around wih some Hydrofluoric acid, 52% disolving the side of a silo that needs to come down. then got the idea of disolving the ceramic base of the catalyst. Made even more sense after the discussions as to the loading of the honey comb, (PT, Rh on one PT, PD on the other)
The "bead" cats are of an alumina base 
Honey comb is mainly silica and alumina.

I started to disolve one with the thought that the alumina would form an Aluminum Fluoride salt, (soluble) and silica would form a fluoride salt as well.
A positive by product is trapped PGMs becoming unlocked.

After draining and rinsing the remaining muck would be reticulated in cold diluted nitric. Hopefully not disolving the palladium. ( just base metals.)

Decanting. Then hot nitric. This time disolving the PD. Decant and precipitate.

Then hot AR for the Platinum.

Im sure there is a better way but its late and Im just finishing disolving the ceramic.


Side note. 
Everything melts. Even ceramic  
My plasma cutter enlighted me to that today.


----------



## Oz (Jun 10, 2009)

DNI,

You may know but others may not, hydrofluoric acid is one of the nastiest things you could come into contact with in chemistry. While I understand why you may consider it useful for cats, it attacks the calcium in your bones, and will literally eat your lab glass. I can only wonder how you came to use it for dissolving a silo that needs to come down???

Please anyone reading this do your research on this acid before trying it! I am not saying it can not be used safely but it requires special considerations that many on here are not prepared for.


----------



## DNIndustry (Jun 10, 2009)

Yes he is right .
I appologize.
It is not to be "played with"
I have a well controlled environment, and all HF experimenting is carried out in HPDE or Teflon containers. It does create huge amounts of vaper so adequate apparatus is needed.

That being said.
The silo.
My shop is on an old farm.
The barn is collapsing as is the silo. the metal roof is just hangin up there.
My buddy who owns it said he takes cement block silos down by chipping out a couple of the base blocks. This one scares him thow. He doesnt want to chip on it but for saftey it really needs to come down.
I told him to let me know when. HF & concentrated H2o2 sprayed out of super soakers at the base blocks....should take about a 6 pack. 
Ill make sure to record it.


----------



## markqf1 (Jun 10, 2009)

I have done a few experiments with HF and have these veiwpoints to offer.

Safety!

Read the literature folks. It's nasty stuff and the fumes are more harmful than the liquid because they are harder to detect on your skin, in a timely manner.
Another safety factor is the disposal of the spent acids as they are not easily reuseable.
It is illegal to introduce these wastes into streams, waterways, or ground water, making disposal difficult and I'm sure costly on a large scale.
It is also, unlike the majority of other acids, not very forgiving if you make a mistake so, I would recommend a 1 to 1 ratio spill kit for anyone using it.
Also, look at the special equipment labware needed to handle it safely.
If you arm yourself with the proper knowledge and safety equipment, it can be used safely but, there is always room for a mistake.

Economics!

The expense of HF, and the transportation costs as well as the associated disposal costs, make it, in my opinion, cost prohibitive.
It is true that the use of HF increases recovery to nearly 100 percent, but if you look at what can be obtained from other cheaper and far less dangerous methods, you'll see that the difference is only a few percent on pt and pd. The only place it really helps you is with the rhodium recovery and at todays prices, it's just not cost effective.
If you haven't already done so, read lasersteve's sticky and you'll see what I mean.

I found (with help from a friend) that, if you mix it 50/50 with water, it works much better and will dissolve more of the substrate.

Mark


----------



## loco (Aug 22, 2009)

DNIndustry said:


> Yes he is right .
> I appologize.
> It is not to be "played with"
> I have a well controlled environment, and all HF experimenting is carried out in HPDE or Teflon containers. It does create huge amounts of vaper so adequate apparatus is needed.
> ...




I am by far a chemist but being as aggressive as HF is, isn't it careless to go about just spraying it out of super soakers? I mean it's nasty enough to eat threw most things what will it do to plant life, wild animals, heck your pets, and ground water ???? I may be outta line but it just seems like it's to mean to not be in a more controlled application.


----------



## qst42know (Aug 23, 2009)

Your local agricultural extension office could likely connect you to an explosives expert to get your silo down safely.


----------



## Irons (Sep 25, 2009)

qst42know said:


> Your local agricultural extension office could likely connect you to an explosives expert to get your silo down safely.




...and in the direction you intended.


----------



## Anonymous (Sep 25, 2009)

HF is sold in a little bronze bottle at walmart for removing iron stains. It does have a warning label, much like everything else. 
Suprised me to see it there. I was looking for oxalic acid, but could not find any, did find sodium hydrosulfite and metasulfite will they work for precip? would be nice to walk down the street and get 1 lb for 2.00 

Jim


----------



## butcher (Sep 25, 2009)

my hardware store sell oxalic acid, wood bleach.

the HF iron removal brown bottles is fairly dilute and I think has other things in it, sold in most grocery stores around here. also the hobby shop carries a stronger solution for etching glass


----------



## bubba (Nov 24, 2011)

DNIndustry said:


> I have been playing around wih some Hydrofluoric acid, .



I saw this and just had to comment, folks this is NASTY stuff, a drop on the skin will eat to the bone, nothing helps except a specific antidote, which names escapes me at the moment, but if you were to "play" with HF, make sure that you or the nearest hospital has this antidote. Alot of metallurgists wont even handle the stuff, at all. Besides, it is far to expensive to be cost effective in processing converters.


----------



## Lou (Nov 24, 2011)

Calcium gluconate or benzalkonium chloride really aren't antidotes, they're more to prevent further damage to your bones by preferentially precipitating the fluoride as CaF2.

I'd recommend against use of HF. Playing around with it is a stupid thing to say.


----------

