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Thoughts About Rock Salt

Discussion in 'Ice Management' started by Winterologist, Jan 4, 2010.

  1. Winterologist

    Winterologist Junior Member
    Messages: 23

    Rock salt is fairly abundent, relatively inexpensive (compared to other deicers) and does a decent job for most snow events. So what does rock salt do on pavement if there's no snow to melt? Nothing! Not until those first snow flakes hit it. What happens then? It starts to "brine out". It starts making that 23% brine that everybody talks about. (By the way, I can't tell you how many people call it "BRIME". I don't know what brime is, but brine is a word commonly associated a manufactured rock salt solution (23.3% rock salt in water) OR natural well brine which contains all of the natural occuring "chlorides" (calcium, magnesium, sodium & potassium + a few other ions in such small amounts that its not worth mentioning). Anyway - brine does all the hard work on the pavement, rock salt does nothing.
    1 lb salt @ 30F melts 46 lbs ice in 5 minutes
    1 lb salt @ 15F melts only 6 lbs ice in 1 hour
    1 lb salt @ -6F (eutictic point) melts only 3 lbs ice in FOREVER ...it'll blow away before it works.
    This is the principle reason that rock salt gets so abused ...it's abundent, it's still kind of cheap - so what, it's only 7F out - we'll just pound down that salt until we get the results as if it was 27F!!!

    What makes rock salt work faster? Other than spiking it with with calcium / mag chlorides or beet juice, consider "gradation". The smaller the particle size, the faster it will brine out. Some equipment manufactures are capitalizing on this concept - they're using a crusher as the salt enters the spinner / auger. So, does this finer gradation work faster? You bet. Is the salt still limited to decreasing effectiveness in lower temps (as listed above)? You bet. So what's the bottom line here: rock salt that looks like table salt will brine out in a heartbeat, HOWEVER, if an event comes in as rain or freezing rain - standard rock salt is king. Why? ...because the longer it takes to brine out those big chunks of salt, you're hoping that the temp is tanking & it's turning to snow. By the way, NO anti-icing, with any chemicals works well when an event comes in as rain or freezing rain - don't waste your money trying.

    Thoughts about mid-winter draws of salt ...I always cringe when I drive by that mountain of salt just South of Detroit in mid-January - untarped - next to the river (there'll be sharks in Lake Erie before ya know it), it's 35F and it's been raining hard for the last 3 or 4 days. Those taking a draw off this pile are in for a rude awakening. This is certainly rain-soaked salt, and the liquid dripping out of the truck that just brought it is brine. That's right, the same thing that's forming around that small salt crystal when it snows, is coming out of that pile = 23% brine = salt water. Will this salt freeze up in your trucks now that it's only 10F? Sure - like an iceburg. Most of the time your rock salt will be no more than 10% moisture. Salt with considerably higher moisture contents will NOT hold an additional 6,8,10,12 gallons per ton of other spiked chlorides or beet juice. It runs our of a salt pile and throws like cow pies off the spinner. It's not a problem with the spike chlorides or the beet juice - rain soaked salt just can't hold that much more liquid.

    Lastly, what's that blue stuff on salt? It's an anti-caking agent added to prevent salt piles from freezing up. This blue dye called Prussian Blue is Ferric Ferrocyanide. Although shown to be relatively benign to human it does brake down into its iron and cyanide components which makes me wonder about lesser species - perhaps in a creekbed along a major highway??? Does the anti-caking work? Sort of. Does it work for that mid-winter draw of rain soaked salt? If you've been in the business for a while, you know the answer to that. If you had to, you could probably eat the blue snow, but don't ever eat the yellow snow.
  2. Westhardt Corp.

    Westhardt Corp. Senior Member
    Messages: 845

    Moral of the story: if you want perfect salt, buy it early--in cash; take it off the barge--not the stockpile; store it in a warehouse.

    This message brought to you by Trump Snow Removal

  3. Mark Oomkes

    Mark Oomkes PlowSite Fanatic
    Messages: 13,256

    Excellent post, other than the red type.

    I disagree with this statement, based on my experiences. Especially if you are only getting a light icing event, under say a quarter inch.

    If you anti-ice you will have little to no ice on your lots while if you don't you will be skating all over them in an attempt to apply salt and melt your way through the layer of ice to get the brine underneath where it is actually effective.

    It is a well known fact that no matter what we are trying to melt, we need to get the brine--which is what melts all snow and ice, not a granule of chloride--it needs to get to the pavement or be there from the get go. This is why anti-icing is effective in reducing salt usage.

    I will say that if it is raining heavily, you will be wasting time and material. But if it starts off as freezing rain, you will be a long way ahead.
  4. Bajak

    Bajak Senior Member
    Messages: 999

    Great category 3 post with some 1 and 2 in there as well.:D

    Here are my thoughts and questions on pretreating for a freezing rain event. I admit, I don't really know much about pre-treating.

    I wont apologize for the metric because I find it easier to work with. I will however give conversions as best I can out of respect for old farts in Canada and those schooled in the U.S.A.

    Ice has a density of 0.9kg/l (2lbs/0.264 us. gal.) @ O*C (32*F)

    If I were to expect a freezing rain event of 5mm (between 1/8 and 1/4 inch) with air temperatures near 0*C and ground temperatures of around -8*C(17.6*F). Why could I expect 1kg of salt, used as pre treatment, to not take care of 10 m sq. (107 ft sq.) of a parking lot?

    10 sq. m x 5mm = 50 l of ice weighing 45 kg(99 lbs.).
    when 1 kg (2.2 lbs) of salt will melt 45 kg of ice in respectable time under these conditions.

    If the salt becomes encapsulated in ice, will it not maintain a brine?

    Will it not at the very least buy some time?

    If the brine freezes, would it not take less salt to 'kick start' the process?

    Glad to see a post again Winterologist. I thought we lost you.:drinkup:
  5. Mark Oomkes

    Mark Oomkes PlowSite Fanatic
    Messages: 13,256

    :popcorn: :popcorn:
  6. Matson Snow

    Matson Snow PlowSite.com Addict
    Messages: 1,985

    Another Great Post...Also some Great info from Mark...Im just gonna sit back and enjoy this one..Its a pleasure to learn from people that know their stuff.....:popcorn:
  7. Westhardt Corp.

    Westhardt Corp. Senior Member
    Messages: 845

    My head hurts. I'm allergic to metric.


    (great posts, though after translating them through Google)
  8. Mark Oomkes

    Mark Oomkes PlowSite Fanatic
    Messages: 13,256

    Hot dang, got another one buffaloed.

    Wait, you weren't referring to me, were you? :gunsfiring:
  9. Bajak

    Bajak Senior Member
    Messages: 999

    Metric is great to work with because I suck at fractions. I have a calculator with metric to imperial conversion.
    I hope no one gets too upset with 5mm being between an eighth and a quarter inch.
    It is actually a 0.196850393 inch.:nod:

    I hope this thread doesn't get too Decorated while we wait for the resident science guy. I'm sure Winterologist will be back with quality answers. I was beginning to think he was Ferris Buellers teacher. Happy to see some humour mixed in the OP.
  10. cretebaby

    cretebaby PlowSite Veteran
    Messages: 4,162


    I have found that pretreating an ice storm is the best way to deal with it.

    Heavy ice is like a heavy snow, you have to keep up to it and not just wait until the end.
  11. Westhardt Corp.

    Westhardt Corp. Senior Member
    Messages: 845


    Actually, metric is easier once you are well versed in it--like you said, no fractions. But, going back & forth in anything other than length just confuzzles me.

  12. Mark Oomkes

    Mark Oomkes PlowSite Fanatic
    Messages: 13,256

    Shoot, I didn't even try to convert, but then again, I understand what he is saying. Basically, Jamie, Jim, Jimmie, James whoever he is was making me look like the dumb snowplower I am by using actual scientific figures.

    He's pretty smart for a Canuck. :salute: tymusic :nod:

    PS I love Ben Stein, he is hilarious.
  13. Westhardt Corp.

    Westhardt Corp. Senior Member
    Messages: 845

    All I know is 25.4 mm = 1 inch. Beyond that, pass a napkin to contain my drooling, please.

  14. TCLA

    TCLA 2000 Club Member
    Messages: 2,707

    Kind of hard to tarp one of these, wouldn't you say?


  15. Westhardt Corp.

    Westhardt Corp. Senior Member
    Messages: 845

  16. Matson Snow

    Matson Snow PlowSite.com Addict
    Messages: 1,985

    Is that the Pile Behind your Shop??....WOW!!!!!...Bragger!!..:laughing::laughing:
  17. Matson Snow

    Matson Snow PlowSite.com Addict
    Messages: 1,985

    I park My work truck about 200 yards from that pile...Nice Neighborhood..:gunsfiring::gunsfiring:
  18. Maine_Train

    Maine_Train Senior Member
    Messages: 462

    Great thread. I love it when I can learn that much while just sittin' around doin' nuthin'. :cool:

    Isn't brime a type of really small shrinp?


    DAFFMOBILEWASH PlowSite.com Addict
    Messages: 1,602

    How much of that pile runs off back into the Detroit river?? We all know about the benifits of salt as a melting agent but what about the enviromental impact on a specific region. I hate when a contractor piles the salt on a quarter inch thick to melt a coating of snow. Sure he might not have to return to resalt for some time but most of the time it goes to waste and down the catch basin.

    Before a major storm I like having a thin layer of calium brine or salt brine down to prevent the adhesion of the snow to the asphalt. Normally applied the night before the event. In the long run it helps in getting the ashalt back to black for having less snow packed regions.

    Great thread and ideas metric or imperial for us on the border!!!
  20. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Excellent post with some real numbers I can chew on....