How Ice Melters Work
When ice melter granules contact ice or snow, they begin to form a brine solution. This brine is central to the melting process, as it will not freeze initially. The brine becomes more diluted as it melts the ice or snow, until it eventually refreezes.
How long it takes for this refreezing to occur depends on the amount of ice melter applied and the effectiveness of each granule. Some ingredients melt ice at lower temperatures, and prevent refreezing longer than others. For example, rock salt will melt ice down to -15°C (5°F), while urea will only melt ice down to -4°C (25°F).
When to Apply Ice Melters
Whenever the safety of pedestrian or vehicular traffic is threatened by a buildup of snow or ice, action should be taken to reduce the risk. The use of granular ice melters should be part of an ice control strategy, along with physical removal of snow and ice. By applying an ice melter before precipitation begins, you can prevent ice from bonding to the surface, and simplify shovelling or plowing.
However, pre-application may cause a brine to refreeze under a heavy snow pack if shovelling or plowing does not occur in a reasonable time. Pre-apply only if you are sure physical snow removal can be accomplished soon after. Here are some guidelines for applying ice melter after precipitation has fallen:
Dry Powdery Snow
Can be shovelled or swept, and may not require the use of ice melter.
Apply ice melter early to prevent ice buildup.
Apply as soon as wet/heavy snow begins falling to prevent it from bonding. When more than two inches accumulate, shovel excess snow and reapply if necessary.
Large Accumulations Of Snow
Anytime the snowfall amounts to more than two inches, plow or shovel first. Then use ice melter to melt the stubborn layer of ice or hard-packed snow that remains.
Apply at labelled rates. Use a spreader or application unit. Spread evenly. Do not over-apply, especially around vegetation, metals and concrete.