In order to extract magnesium from brine, another ingredient is needed. Calcined dolime also provides another source of magnesium. An aqueous suspension containing solid particles is also referred to as a slurry. Gravity is used to separate the solids from the liquid in the aqueous suspension since magnesium hydroxide is heavier than water. If you look at a bottle of milk of magnesia, which you probably have in your bathroom medicine chest, you'll see this separation clearly.
Milk of magnesia is another name for magnesium hydroxide.
The blue color indicates the watery layer containing dissolved magnesium chloride that has formed above the settled magnesium hydroxide particles. The bottom solids are then filtered to remove any remaining water and given a series of water washes to remove chlorides from the material. Rotary kiln pictured in foreground Several types of kilns can be used in the calcination step. Calcination not only converts magnesium hydroxide to magnesium oxide, but is also the most important step for determining how the final product will be used. Exposure to thermal degradation causes this particle to alter its structure so that the surface pores are slowly filled in while the particle edges become more rounded.