Manufacture of Synthetic Hydrotalcite (Halogen Scavenger Grade)

An improved process is described for the preparation of surface modified hydrotalcite.

Bittern and soda ash are reacted to make magnesium precursor. Aluminium sulphate and soda ash solutions are reacted to make aluminium precursor. These precursors are blended and subjected to hydrothermal treatment under optimized process conditions. The slurry is filtered, dried, pulverized and sieved to obtain pharmaceutical grade SHT.

• Cheaply and easily available sea bittern and non- ferric alum has been used as a source of magnesium and aluminium compound respectively.
• The mother liquor after crystallization can be reused.
• The process does not require costly equipment for drying i.e. spray drier.