What is it, really? It can’t be just alcohol, that would be too simple. They want $12.95 a gallon for it, whatever it is, $39.95 if you buy the whole kit with the sprayer.
I doubt that throwing alcohol on your driveway would keep melting away the snow and ice for 14 days…there must be something else to it. However…
…you know those “lock de-icers” you see in the checkout lane of your local grocery/hardware store? Those ARE just containers of plain old rubbing alcohol…and they’re selling those little tiny containers of the stuff for $2 or so! You can buy 10 times as much at the grocery for about $0.99! Just pour that stuff on your car key, stick it in the door lock and PRESTO! De-iced door lock!
Says that one kind of agricultural de-icer is calcium magnesium propionate: Ca[sup]2+[/sup] Mg[sup]2+/sup[sub]4[/sub]
The stuff you’re asking about could be any one of a huge number of water-soluble organic compounds (or a mixture of them). Being water-soluble is all it takes to melt ice, and distilleries and food processing plants could produce any number of suitable chemicals. Calcium magnesium propionate and a lot of other chemicals have an advantage over alcohol in that they won’t just evaporate when you put them on the ice. They’re probably a lot more expensive than salt, but they’re less corrosive and won’t kill plants (as bad). Some of them can be applied as liquids or solutions, which has its advantages, and some can be applied before ice forms to prevent its formation.
All that really matters is the concentration of solute, not its freezing point. Salt, for example, has a freezing point of 801 degrees Centigrade and it melts ice.
So, um, what is it when it’s at home? I love it when 50 cent polysyllabic Mr. White Coat Scientist words get reduced to something like “soap” or “booze”.
Other common de-icing substances are ammonium nitrate and ammonium urate. I don’t know how effective they are, relatively speaking, as de-icers, but they actually act as fertilizers, and will probably make your grass a bit healthier.
As to freezing/melting point: Consider water/ice. If you cool liquid water down to zero C (32 F), it’ll turn to ice, so 0 is the freezing point of water. Similarly, if you take solid ice and heat it up to 0 C, it’ll melt, so 0 is also the melting point. It’s the same way for all substances.
The freezing point of salt is 801 degrees centigrade if you start with molten salt and cool it to that temperature, at which point it “freezes” (becomes solid).
The melting point of salt is 801 degrees centigrade if you start with frozen (solid) salt and heat it up to (actually a bit more than) 801 degrees centigrade, wherupon, it melts.
Simple, no?
~~Baloo
[sup]Expects this explanation to generate yet another question despite its simplicity. Someone else field the next one, huh?[/sup]
It sounds like the stuff they have been using at my college this winter. I was told it’s some sort of hops extract and is more enviro-friendly than salt. Makes the whole campus smell like molasses but it seems to work.
Sounds kind of like the goop we de-iced aircraft with when I was stationed at Fairchild. That stuff smelled like maple syrup. Never tried to taste it though. After all, we kept it in a HUGE tank out at the “tank farm”. They told us it was nontoxic and biodegradeable, but also warned us not to breathe the fumes(?!?). Everything in all the other tanks made jets fly, so I wasn’t tempted to give it the taste test.
Thanks, Baloo. Sadly, I grasped this concept at the exact moment I hit “Submit” for my earlier post. I tried to recall the post, and I thought I had – it didn’t show up on the screen when I checked the thread immediately thereafter. Unfortunately, my momentary lapse in judgement and mental ability is now visible for all to see.