Puester wrote:
> JB wrote:
>
> > Can you use salt which is intended for an ice cream maker or to melt
> > snow and ice on the sidewalk in a salt mill?
>
> I wouldn't. You have no guarantee of purity and
> there may be other ice-melting chemicals added
> in addition to natural impurities.

The stuff put on roads isn't very clean. They don't put much effort into
purity. Not good enough for most cooking uses unless you want unpleasant
results.

These salts can be almost any mixture of sodium, calcium and potassium
chlorides. Sodium chloride comes in reasonable purity (95%+) from salt
mines, and without any further refinement that's what is put onto roads.

I noticed that the "salt" that is put onto sidewalks is labelled calcium
chloride. On of the men at my lodge is a retired civil engineer who
specialized in roads, so I asked him about that. He said that calcium
chloride will melt ice down to -20F where sodium chloride will only melt
ice down to 0F. But because of the price, highway crews use roughly 90%
sodium chloride in whatever purity it was straight from the mine and add
roughly 10% calcium chloride to increase the melting power.

Anyways, calcium, potassium and sodium chlorides are all good mineral
sources. I'd worry about the other impurities though.