Road Salt: How Hygroscopic?

I mean the stuff that our state uses on highways: big, irregular yellowish crystals. They always seem to be slightly wet.
I come away from Googling with the impression that as long as the humidity is over 75%, road salt will be absorbing water.
I've got a couple of 5-gallon buckets of it that I am saving for next winter and wonder if it is worth leaving the buckets uncovered for a few weeks of lower-humidity weather in hopes of drying it out.
Does the stuff dry out? Or is the water adsorption a one-way street?
--
Pete Cresswell

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On 03/09/2015 3:32 PM, (PeteCresswell) wrote:

In open air it'll just form a solid mass anywhere except AZ desert-like area. You can dry it of course, but only w/ an _extremely_ dry environment. A hot attic during the summer would be a good example if it's not on the coast where humidities are high year-round, anyways.
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wrote:

I used to see it stored outside and I would not be shocked if they wet it down before they spread it anyway so it wouldn't be clumped up and it would feed better in the spreader. When I was in Maryland I helped a salt truck guy get unstuck and he gave me a 30 gallon can of salt but it ended up being a 30 gallon solid rock by the next year. I chipped away with it with a hatchet for a couple seasons until it was all gone.
The DOT guys I know down here in Florida will not be much help with road salt tips.
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wrote:

They used to sell bags of CaCl, I think it was, to hang in the closet with one's clothes to keep the closet dry. Try to find the instructions for using that. I had a bag, and iirc the instructions said that to dry it out to put it in the oven at a particular temp (not so hight the cloth bag fell apart or burned up) for a length of time, in the hours iirc, and that woudl dry it out.
They still have little bags of "that stuff????" that come shipped with electronics and cameras.
I had a flooded basement that started to smell of mold, so I bought a 50 pound bag of salt of some sort, at a janitorial supply store. I took a plastic bucket and some of that brown masonite-like stfuff with the filligree holes in it, that was hot stuff in the '50's, and I cut a piece to divide the bucket vertically. I put the salt in one side of the bucket and I put the bucket where I smelled mold. The next day there was an inch of water in the bottom, probably on both sides, but I could see it and when it was fuller, puur it out from the side that was otherwise empty.
Strangely, the smell disappeared only where hte bucket was. I actually noticed the smell more when I was walking up the basment steps, so I put the bucket on a step. In a day or two, the smell was gone from that step, but I could still smell it on the others. I had to put the bucket on each step in turn. What's stranger is that my nose was about 5 feet higher than the bucket, but it still worked this way. I poured out a lot of water, maybe put in salt a second time. Eventually I got rid of all the smell and I gave most of the bag to a gas station I thought might need it. A 50 pound bag was still a lot cheaper than a whole bunch of 4 oz. bags.
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On 3/9/2015 5:45 PM, micky wrote:

Calcium chloride is not only hygroscopic it is deliquescent:
https://vimeo.com/2670546
Road salt is mostly sodium chloride - not hygroscopic. If you use it, best to keep off concrete as it degrades it.
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On 2015-03-09 5:45 PM, micky wrote:

I don't understand how this is working. The Road Salt is absorbing the water? The mold dies because there is no water?
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wrote:

I don't get it either. I guess it was road salt. That's something that a janitorial supply house would have too, for siidewalks and parking lots. It was absorbing the water from the air.
When my basement flooded, I coudln't throw away everything that got wet. Most of it was cardboard boxes that sat on the floor and held things. It took a long time to find stronger than average boxes in the sizes I needed. So I just let them dry out. None of the boxes every showed any mold or ever smelled bad -- I still have most of them --, but they probably kept the humidity level in the basement higher than normal.
So the mold started growing on a sheet rock wall, that was painted white. When I found the black stuff (behind a dresser I used for tools) I used bleach to kill the mold. The black area stopped getting bigger, so the mold must have been dead. I thought the black area would change to white again, but that must have come from watching too many wolfman movies. When I realized it woudln't turn white on it's own, I painted it white, having added mold "suppressor" or whatever it's called, to the paint.
Yet the basement smelled bad, even to me, and I'm not very picky.
Now that I think about it, I'd probably had the bucket in the middle of the room for a couple weeks or more, water filling up the otherwise empty side, and periodically I'd dump the water, salty water I guess (it certainly wasn't clear and transparent), in the laundry tub and it would go down the drain.
And I'm sure I added more salt to the bucket, probably twice, and iirc the smell in the main part of the basement went away, but it still smelled when I started to walk up the stairs. The floor is either cement or vinyl tiles, but the stairs are carpeted, with padding, and I had no idea what the carpet might have absorbed. But the real amazing thing was what I said. I'd put the bucket on a step for one, two days, or even if it was 3 or 4, and the smell would go away when I stood on that step, with my nose 5 feet above the carpet. I think maybe then I moved the bucket two steps up, but later I had to go back and put the bucket on the step I skipped, to get rid of the smell when I stood on that step.
I don't get it, but it's confirmed my pre-existing habit of trying all sorts of remedies, even if I don't think they have any good reason to work.
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(PeteCresswell) wrote:

Hi, Any salt including table salt(NaCl) will absorb moisture.
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On 3/9/2015 4:32 PM, (PeteCresswell) wrote:

There are more than one chemical used in road salt.
Sodium chloride is minimally hygro, calcium chloride is very hygro. http://www.riverheadlocal.com/2015/03/03/officials-face-critical-road-salt-shortage-winter-storms-approach-no-deliveries-sight/
http://www.mpnnow.com/article/20150302/News/150309963
Not clear if it's sodium or calcium. Used to be a salt mine in our state, in Retsof, but not sure that mine is active. Some concerns about runoff and ground water. Our state also has a lot of rusted out vehicles.
- . Christopher A. Young learn more about Jesus . www.lds.org . .
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On 3/9/2015 4:32 PM, (PeteCresswell) wrote:

Keep it under roof, like a shed or garage. If it's already wet, chances are it will be a huge clump.
Your State may be using Moroccan salt. Some States barged over hundreds of thousands of tons, since a shortage was anticipated. Most if not all States spec out their salt size, but this salt from Morocco is huge. I just hauled some Moroccan salt from the Great Lakes area, even tho there are salt mines under the lakes! I did notice the salt appeared to wet. And no, it's not supposed to be wet, that is what activates it. That's another subject, but trucks have a pre-wetting system on them, which can be filled with brine/beet juice/ or calcium. There's a whole slew of new liquid products on the market for pre-wetting.
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On 2015-03-10 11:21 PM, Tyler B. wrote:

The pre-wetting is just so the salt doesn't bounce around as much. In Ontario, the provincial system no longer uses pre-wet, since we assume the roads are wet with snow or frozen rain when the salt is dropped.
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On 3/11/2015 7:10 AM, Adam Kubias wrote:

Um no it isn't. It's a tool to manage deicing. Brine to prewet is used at 20+ degrees, Beet-Heat is used down to 10 degrees, and liquid calcium is for under 10 degrees. The spinner speed along with the speed of the truck, which both help control bounce. To say pre-wetting is _JUST_ for control of bounce is a WAG and nothing more. You adjust the system to put down 5 to 8 gallons of liquid for every ton of material. If you haven't seen how quick you can deice with settings set to pump 25 to 40 gallons per ton, then you really don't have an idea of what you're talking about.
With over 15 years of experience and constant training, I believe I know a bit about managing storms.
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On 2015-03-11 10:46 PM, Tyler B. wrote:

WAG?
Regardless of your experience, this is the provincial policy in Ontario. The only trucks that run any liquid are the DLA trucks, which run on dry roads, but rarely (usually in the beginning and end of the season).
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On 3/12/2015 2:35 AM, Adam Kubias wrote:

Yes, a WAG. You can look up the facts on the net.
Think of it this way. Not all snow melts the same unless the conditions are identical. The colder the temperature, the more salt is needed to melt the snow. You have to take into consideration winds, air temperature, road temperature, & snow fall. You either throw a bunch of salt at it, or use an additive, which is cheaper and faster acting than salt alone. You take into consideration bridges and ramps, which freeze quicker than an expressway and are treated differently than an expressway surface. You take into consideration traffic, which helps keep the roadway more clear than an rarely traveled rural road. Each of our trucks have air/road temp gauges. We have a host of information readily available at our finger tips for bridge temps/frost/frozen, traffic conditions (if they're in the green/yellow/red areas for movement). So you see, pre-wetting is not _JUST_ for bounce.
The trucks you are trying to explain are no doubt brining or what is commonly called pre-treating. I operate a 5,000 gallon semi-tanker with a unit built in Canada for pre-treating.
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On 2015-03-12 11:02 PM, Tyler B. wrote:

After googling WAG, the only definition that came up is Wives and Girlfriends, which I could have answered anyways. Still doesn't make sense in context.
You are correct that it is an over-generalization, but why does it bother you so much that I wrote it?
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wrote:

Wild Ayed Guess

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On 3/13/2015 12:23 AM, Adam Kubias wrote:

It doesn't bother me that you don't know what you're talking about.
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