What to do with a broken alum block

[thedave87]

The other day my RazoRock alum finally eroded enough that it fell out of its handle, hit the sink, and cracked into pieces. I picked the pieces up, rubbed the smoothest piece on my face, and ordered a new one to replace it. The pieces sat in my medicine cabinet for a few days until I got to wondering what I could do with a broken block of alum. The block I replaced it with was a second/blemished unit from Maggard's, and they made mention of using it to "melt down and re-form into custom shaped blocks". This got the gears turning. I researched out melting alum, and it seems that it's melting point is 198-199 degrees Fahrenheit (93 degrees Celsius). So armed with a broken alum block, a double boiler and a silicone muffin wrapper I set out and did some science.


This is my broken block...



This is my broken block in the pan...



After a couple minutes, I decided that crushed pieces would melt faster and more uniform than the large chunks, so I put them in a baggie and smacked them with a meat tenderizer.



After 6 total minutes in the boiler, the pieces began to melt and look like melting ice.



At 11 total minutes, the liquid began to get foamy and take on a bluish hue. I'm no chemist, and never even took chemistry in high school, but I'm pretty sure I didn't want this to happen.

According to Wikipedia:

When heated they liquefy; and if the heating is continued, the water of crystallization is driven off, the salt froths and swells, and at last an amorphous powder remains.

That explains the foaming, but not the blueish tint.

Continuing in a reply as I'm out of image attachments for this post...

 

[thedave87]

So after that, I let it go for a few more minutes while stirring and decided I needed to pour it now, even if it wasn't 100% melted.



After cooling for 20 minutes, I was able to peel the mold off of it. It definitely has a very odd blue-green hue to it.



I ran a little water over it to see if it would act like a normal block of alum would. After it dried, it did this.


Now that the dust has settled, I think I would be willing to give this another try after changing a few things. I think that the broken block needs to be turned into a powder, or at the least something resembling kosher salt. The bit of it that was like that melted fast, and had I not waited on the bigger chunks to melt, I wouldn't have over-heated it. I would imagine that pouring it while clear and not foamy would be the best way to do this.
As I said before, I'm no chemist and really have no idea what I'm doing. Just trying things that seem possible. I'm in no way asking anyone to do this too and if you do, I won't be responsible for any ruined cookware (pretty sure I ruined a pan) and angry wives (or anything else for that matter). That said, I think this has some merit and I definitely will try again next time gravity forces a meeting between alum and porcelain.

 

[BSAGuy]

So, is this the intermission?

 

[the_edski]

Could the tint be from any mineral deposits on the pan from a previous wash?

 

[BRITD]

Looks like a lost episode of breaking bad. View attachment 582388

 

[Terp61]

Looks nasty.

 

[imatabor]

Looks like a lost episode of breaking bad. View attachment 582388

 

[mc3533]

Just dropped mine earlier in the week, tossed it and ordered another.

 

[nick_s]

Walter White lives

Question is, does it still work like it used to?

 

[Ad Astra]

Wow! Did it turn into something else?

I mean, it's a mineral. You know; if it was harmless and beneficial EAc3b, maybe now it's changed into deadly EAc4b.

Alum DOES put a layer of acid on your face ...


AA

 

[aldomarino]

I'm no chemist, but I wouldn't put that on my skin.

Me, I just buy the broken up rocks anyway. Way way cheaper than buying it in blocks.

 

[fightingillini22]

 

[Ad Astra]

We need someone in glasses and a lab coat to weigh in on this ... the blue color shift is unexplained.

(cups hands and shouts) "Is there a chemist in the house?"


AA

 

[ackvil]

Any story like this should start off with "Once upon a time" and have a happy ending!

 

[timnohair]

The bluish tint is a little metal from the pan. Alum mixes very easily with water. Do it at room temperature and in a ceramic or glass bowl. You will have liquid in minutes and you can put it in a form as you like.

 

[thedave87]

Walter White lives

Question is, does it still work like it used to?

I'm not brave enough to try it. I did wet it and run my fingers over it. It doesn't leave that tackiness on the fingers that it used to. The color change and weird feel to it makes me not want to put it anywhere near my face. I'm willing to try this again, and pour it before it foams. I think that might keep it from getting blue. No one likes sad alum.

 

[bluesman 7]

I think you want to dissolve it in a glass container, then grow the crystal by suspending a small piece of the alum on monofilament fishing line in the solution. There is a thread about this somewhere. Alum is used this way to show kids how to grow crystals.

 

[matt71]

I'm a chemist. What exactly is your question?

Edit: and I certainly would not use anhydrous alum on my skin. Ever see blue alum for sale at a shave supplier?

 

[Ad Astra]

I'm a chemist. What exactly is your question?

Edit: and I certainly would not use anhydrous alum on my skin. Ever see blue alum for sale at a shave supplier?

So; the new "Aqua Velva (looking)" alum block underwent a molecular re-arrangement and is no longer safe? or just blue?


AA

 

[matt71]

So; the new "Aqua Velva (looking)" alum block underwent a molecular re-arrangement and is no longer safe? or just blue?


AA

You lost some of the hydrate (KAl(SO[SUB]4[/SUB])[SUB]2[/SUB].12(H[SUB]2[/SUB]O)) -> [less than 12H2O]
You broke down the organized lattice crystalline into a more random amorphous structure (think Jenga with a 3D lattice)
When you exposed to water, it rehydrated and gave you the white back (but not the crystalline)


I would say there is some potassium/aluminum sulfate you have that is blue. I'd have to dig a bit, right now I'm at the paying chemist part of the day, so I'll have to get back to you.

Since I don't know for a fact it is safe, I would assume it is unsafe.

Also, the first pic, looked like you could have used the left side of the stick still?

I would imagine to recrystallize now would be difficult.

More later when I can play.