By treating brines with the EFC method, potable water and pure salts can be recovered (Randall, 2010). The operation principle of the process can be described is as follows. When the salt solution is slowly frozen, water ice crystals form on the surface and can be separated from the solution. The salt is concentrated in the remaining solution. The salt will crystallizes at its eutectic temperature and therefore it can be separated from the solution as a salt product (Nathoo, 2009).
A mixed salt product can be avoided by producing many pure salts, each at their unique crystallization temperatures. The advantages of this process are that it is not complicated by chemical addition, it is a less energy intensive process in comparison to evaporation, and the ice crystals are pure water. The ice crystals that are produced can also be used for cold heat storage and gravitational separation of the ice and salt crystals are an added advantage during EFC since both products are separated by density difference. The salt sinks to the bottom while ice floats on top.
The sequential removal of individual salts form brine is theoretically possible since each salt crystallizes at its own unique eutectic temperature (Randall, 2010). Though, this is not yet proven.
