Thermal decomposition of potassium nitrate

[raivo]

I took 3g of KNO3 and put it onto small stainless steel bowl. I expected that if i heat it it will decompose to K2O and some nitric oxides by rather wild bubbling. KNO3 melted almost instantly and when i continued heating KNO3 was still liquid and completely quiet. Just stainless steel had some reddish glow that was clearly visible through liquid nitrate.

 

How to decompose KNO3 not going to still higher temperatures? I want to make some KOH from it. ( Just experimenting on various uses of nitrates. )

[YT2095]

sounds like you just ended up making KNO2 (Potassium Nitrite).

 

if you need KOH, why not strip down some old/dead alkaline batteries (the blue/grey paste in the middle) and mix that in with hot water, let it settle then filter off the liquid, that`ll be your KOH soln

 

AND you`ll be helping the environment by re-cycling!

[raivo]

It seems that you are right. At once after the melting there was some small bubbling. So it was oxygen. I thought it is H2O because i was not sure how dry may KNO3 is.

[Gilded]

"sounds like you just ended up making KNO2 (Potassium Nitrite)."

 

Isn't that the stuff that one might use to make certain stuff?

[Silencer]

^Fireworks, black powder, etc. That thread is still going on...

 

What is the KOH usefull for, because I have a few batteries laying around that I want to bust open.

 

Also, is using a hack saw safe on the batteries? I don't want to corrode the blade (it's my dads) or inadvertantly start a reaction.

[folder]

I use a dremel cutting wheel to open batteries. The Zinc (if it's a zinc-carbon battery) outer shell and carbon rods you might want to keep, because they can come in handy.

[Silencer]

^Yes that's the purpose of opening them.

 

The dremmel sounds like a good idea.

[Gilded]

"^Fireworks, black powder, etc. That thread is still going on..."

 

I don't think you'd like to use potassium NITRITE in black powder mate.

[boris_73]

to open batteries i use wire cutters small hand held ones i cut i hole in the top of the battery then pull apart and to get the black powder out i cut the length of the battery downwards and it just crumbles out, that simple brute force:)))

[Gilded]

"to get the black powder out i cut the length of the battery downwards and it just crumbles out, that simple brute force:)))"

 

Do people ask where you got your muscles and then you just say "I've cut a lot of batteries in my life"?

[YT2095]

actualy for Alkaline batts, there`s no Sawing needed to be done at all!

all you need is a pair of good wire cutters (as stated).

 

take the outer case off, pull the pin out (the bit that`s seperated from the case with the plastic ring.

then from that end, peel away some of the metal case. you`ll see a grey/blue paste in there, scrape that out with a screwdriver into a flask or beaker.

repeat proccess until all batts are finished.

 

add boiling water to the beaker/flask and stir well, leave it over night.

 

filter off the liquid and store it.

 

 

that`s ALL you need do, nothing else!

[Gilded]

"filter off the liquid and store it."

 

A KOH solution yes, but can KOH exist in a solid form and if it can, how safe it actually is as a solid? And could you just boil the water off to make KOH crystals?

[YT2095]

yes it can/does and sure you could

 

I just pref to keep mine as a soln, I have rare to never needed it in Solid form.

 

also I just buy mine now, but that wasn`t always the case, I used to use this mehtod all the time before I could purchase it pure

[Gilded]

"I just pref to keep mine as a soln, I have rare to never needed it in Solid form :)"

 

What do you need it for anyway? I think I remember you using a KOH solution in your LED-battery-challenge thing, so that's probably one use.

[YT2095]

I used NaOH for that.

 

but to answer your question, i use it for a Multitude of reasons, as a Reagent in Titration, for Salt conversion, for displacement reactions, for the K part in N-P-K plants foods that I design, and also for making Hand Soaps

 

yes, it`s a quite a well used product here

[jdurg]

Yeah, KOH easily exists in a solid form. But like NaOH, RbOH, and CsOH, it is quite deliquescent. I.E. it readily absorbs carbon dioxide and water from the air so it's hard to keep it 'pure'.

 

KOH is used to make liquid soaps if I recall properly.

[YT2095]

KOH is used to make liquid soaps if I recall properly.

yup, or Syrupy soaps as I call them

 

great in the "disspoasble" dispensers, I keep them and re-fill `em. fantastic for shifting the dirt after a good day in the garden

[Silencer]

The guy in fight club made his own soap too... and some other things

 

Something you don't want the feds to know YT?

 

Lol, jk. The powdery shit in batteries is manganese dioxide? Anything else? (google gives hits, but none of them give the specific composition of the electrolyte).

[budullewraagh]

yeah, there are a few things; manganese dioxide, black carbon and various electrolytes, namely KOH

[YT2095]

in an alkaline cell there`s no poweder stuff, only a paste in the center core, that usefull to you.

be carefull with it though, it`s very corrosive to skin and or Eye balls!

[Silencer]

I definately got some on my hands trying to bust the thing open, but my skin is fine. Probably because I washed them well?

[budullewraagh]

probably. if it feels slippery you have your hydroxide

[Gilded]

"if it feels slippery you have your hydroxide"

 

I hope you're not encouraging people to grab KOH with their bare hands though.