Rahul Magnesia Pvt Ltd is one of the leading producers of magnesium oxide and magnesium hydroxide in India. This article gives a brief info about the production process of magnesium oxide and magnesium hydroxide at Rahul Mag.
Naturally occurring brine, which is a mixture of calcium chloride, magnesium chloride and water, is mixed up with both water and dolime (again a mixture of calcium oxide and magnesium oxide) to produce an aqueous suspension which contains magnesium hydroxide and calcium chloride. This is a usual synthetic magnesia process.
The calcium chloride and magnesium hydroxide thus produced from this reaction are existent together, but in two separate physical states i.e. calcium chloride is dissolved in the aqueous phase while the magnesium hydroxide is formed as solid particles. This aqueous suspension which contains solid particles is also known as slurry.
Now, the solids are separated from the liquid in the aqueous suspension using gravitational force as magnesium hydroxide is heavier than water. Another name for magnesium hydroxide is Milk of Magnesia. The freshly prepared magnesium hydroxide slurry is pumped over to a holding tank and is allowed to settle. There is also blue color visible in this slurry that indicates the watery layer containing dissolved magnesium chloride that has formed above the settled solid particles of magnesium hydroxide.
Then using a drum filter, the bottom solids are filtered to remove any remaining liquid and after a series of water washes, the chlorides are removed from the material. Finally, the washed filter cake is directed to a source of heat, in a rotary kiln, where it is thermally decomposed or calcined to produce magnesium oxide. The water molecules are evaporated during this process.
There are various types of kilns that are used in the calcination process as calcination not only converts magnesium hydroxide to magnesium oxide, but as an important process, it also determines how the final product is to be used.
The complete manufacturing process is undertaken with quality essentials and checks at various levels to deliver best quality products.