Welcome to the dog days of winter.
We've already had that first snow storm of the season around the holidays followed by a blast of arctic temperatures. Nobody wants to be "that neighbor" that didn't shovel or de-ice their property, but what's the difference between rock salt and other de-icers? I've put together a primer that will tell you what melting agents are plant-safe, kid-safe and how to keep your walkways safe for everyone.
Rock Salt is sodium chloride and is a mined mineral with some impurities. It is a hard crystal that has some traction qualities to it. It is also the least expensive per lb. The down side to the material is that more has to be applied per square foot than other materials require and just as ocean water freezes, this material fails to work at lower temperatures. When temperatures are below 20 degrees it really doesn't perform well. Another downside to it is that it is corrosive to metal. It is also toxic to grass and plants and with excessive use it will render a soil to be sterile to plant life.
Calcium Chloride has the lowest melting point being -59 degrees. When it comes in contact with ice it immediately heats up and melts the ice or snow. It is more toxic than rock salt and has a high available chloride content similar to rock salt. It is the fastest acting of all the ice melting agents. The white bead can break down with water and leave a slimy coating if put down too heavy.
Magnesium Chloride will melt down to -15 degrees. It is less toxic than baking soda and has a chloride content approx. 50% of rock salt. It is much kinder to the environment and safer to use around kids and pets. It is also used as a dust controlling agent in horse arenas.
Potassium Chloride melts ice down to +12 degrees and is used in the fertilizer industry as marinate of potash. It is a hard mined crystal and has some traction quality. It is not as corrosive as calcium chloride or rock salt, it's also used by plants as a nutrient and thus will not harm plants if not over applied.
Urea is a nitrogen fertilizer. It is used by airports as an ice melter because it will not corrode expensive aircraft. It has no chlorides and melts down to 15 degrees. It is considered safe to use around pets and children.
Scaling of concrete is a major concern for property owners. It occurs from rapid heating and cooling of cement. It is more likely to occur with calcium chloride and sodium chloride. It usually is a concern when ice melting products are overly applied or unevenly applied. It is alway is best to follow directions and use a spreader.
For those of you who can't get enough of this subject (and we know you're out there) visit Peters Chemical Company for the the final word on ice melters. Feel free to stop by Morrison's and we can show you the best product for your application.