15 - Creeping Salt

When concentrated brine (water and dissolved salt) is allowed to evaporate in a container, the salt precipitates and forms small crystals. But more surprisingly, many crystals form outside the container. The salt crawls away from the walls of the container and may cover the outer walls or climb up a plunging rod. Explain the phenomenon. What is the maximum height that salt crystals can reach on the rod ? Maximize the amount of salt that can be extracted on the rod per unit volume of evaporated solution via this method.