When ice melter granules contact ice or snow, they begin to form a brine solution that is central to the melting process.
The solution bores through the ice or packed snow, and when it reaches the surface, it spreads out and loosens the bond between the surface and ice to make the removal of snow and ice easier.
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 applied and the effectiveness of each granule.
For surfaces that have the potential for damage (e.g.: concrete), remove slush as it is formed.