| abstract |
A process for simultaneously removing silica and reducing the overall hardness of natural water or waste water containing silica and scale forming ions is described. The process adds (i) magnesium hydroxide or a precursor of magnesium hydroxide and (ii) a soluble aluminate compound or a precursor of aluminate to the water while maintaining the pH of the stream at pH> 8, thereby double layer hydroxide at the base. Production, wherein the bilayer hydroxide contains scale-forming ions in the lattice of this bilayer hydroxide, and silica is incorporated in the lattice of the bilayer hydroxide as an intermediate layer anion and / or the bilayer through one or more bonding methods. Bound by hydroxide. |