(i) diluting sea-birtem of 28 to 36° Baume with water to get 2% (w/v) magnesium concentration,(ii) clarifying this bittern by treating with non-ferric aluminum sulfate having alum concentration and aluminum ion concentration as herein described and 1-2N of caustic soda solution to precipitate aluminum and magnesium as hydroxide in the range of 75-100 ppm and 200-300 ppm, espectively,(iii) sededimenting the resultant mixture to obtain a clear solution of bittern having magnesium ions concentration in the range of 0.53 to 0.90 molar,(ivj preparing an aqueous slurry of magnesium precursors by reacting clear bittern obtained in step (iii) with sodium, carbonate solution under continuous stirring while maintaining the mole ratio of carbonate to magnesium in the range of 1.1 to 1.4 at ambient temperature for a period in the range of 30 to 60 minutes,(v) preparing an aqueous slurry of aluminum precursor by reacting solutions of non-ferric alum containing 1.0 to 2.2% Al203 (w/v) with sodium carbonatesolution under continuous stirring while maintaining the mole ratio of carbonate to aluminum in the range of 1.70 to 1.95 in a time period of 30 to 60 minutes at ambient temperature,(vi) the two precursors as obtained in (iv) and (v) by known filtration method in a single unit operation,(vii) washing the cake with dimineralised water till free from chloride and sulphate ions,(viii) redispersing uniformly the wet cake to obtain a slurry of both precursors containing mole fractions of aluminum ions in the range of 0.23 to 0.27 indimineralised water for 1 hour at ambient temperature,(ix) treating the slurry obtained in step (viii) under continuous stirring with solution of 2N caustic soda to obtain 0.8 equivalent of alkali per equivalent ofmagnesium ions in the slurry at ambient temperature for a period of 90 minutes, stirring continued till mother liquor is free from hydroxide,(x) crystallizing, under agitation the resultant slurry so obtained in step (ix) at 70 to 100C for a period of 1 to 5 hours.(xi) filtering the solution by known methods as herein described to obtain wet cake of hydrotaleite.(xii) washing The cake with dimineralised water till the pH of effluent is between 10 to 11.(xiii) drying the said wet cake at temperature not exceeding 110C,(xiv) pulverising to obtain the product in powder form.