The Solvay Process
The most common method to produce "synthetic" calcium chloride is the Solvay process. The basic raw materials are limestone and sodium chloride brine and the reaction can be summarised as:
In reality, the reaction comprises several rather complicated steps. A Solvay process facility is a rather big and expensive undertaking. It should be noted that the purpose of the Solvay process is to produce soda ash, Na2CO3, rather than calcium chloride.
The calcium chloride obtained is a 10-15% solution that also contains a percentage of sodium chloride. This stream can be purified and concentrated utilising the same methods as those used for natural brines. It is also relatively common to simply discard the solution by pumping it into the sea. Consequently, purifying and concentrating the calcium chloride and subsequently putting it on the market can be regarded as a method to decrease the environmental impact of a soda ash plant.
TETRA utilises the effluent from a soda ash plant in Delfzijl, the Netherlands (view process) to produce calcium chloride solutions. | 
