How are magnesium-rich brines concentrated before processing?

Magnesium-rich brines are concentrated for processing primarily through two methods:

• Solar Evaporation: Naturally occurring magnesium-containing brines are concentrated in large, shallow ponds using solar evaporation. In some regions, this process is accelerated by adding dye to the water, which increases heat absorption from sunlight.12
• Industrial Evaporation: In specific industrial processes, such as the Norsk Hydro process, purified brine is concentrated through controlled evaporation stages to increase its magnesium content—for example, raising it from approximately 8.5 percent to 14 percent—before it is converted into particulates for further dehydration.3

Additionally, in the production of magnesium chloride from seawater, magnesium hydroxide is precipitated using dolomite, filtered, and then reacted with hydrochloric acid to create a magnesium chloride solution, which is subsequently dried through a series of evaporation steps.3