A novel process for preparation of synthetic hydrotalcite from industrial waste

The present invention relates to development of a novel process for preparation of synthetic hydrotalcite from three industrial wastes such as aluminium chloride waste- generated in any of reaction where anhydrous aluminium chloride is used as Leawis acid catalyst such as Freidel Craft reaction, bittern containing magnesium compounds generated in solar salt work using brines such as sea brine and subsoil brines containing magnesium, and ammonium carbonate solution generated in organic pigment industries such as producing copper pthalo cyanin green. The process involves preparation of aluminium precursor and removing metallic impurities present in Aluminium hydroxide prepared from aluminium chloride containing waste, preparation of magnesium precursor , mixing the precursors, hydrothermally treating the mixture and adding surface modifying agents followed by filtration and drying. The hydrotalcite prepared exhibits surface area (BET N2) of product activated at 200° C. for 1 hr ≤20 m2/gm, average particle size (by volume) of around ≤0.5 µm, at least 90% particles are under 1 µm, and free from amorphous as well as crystalline impurities as judged from IR and XRD.