Patent ID: 8241483
Filing Date: 2012-08-14
Classification: A23L,C01F,C01P

Abstract:
1. A process for the preparation of stable iodate-exchanged hydrotalcite with zero effluent discharge, the process comprising the following steps: a) calcining powdered carbonate-exchanged synthetic hydrotalcite at 450 to 550° C. and treating the calcined hydrotalcite with a known amount of aqueous alkali metal iodate salt solution to obtain a slurry having 80-85% of the iodate intercalate into the synthetic hydrotalcite while generating a stoichiometric equivalent of hydroxide ion which remains present in the solution along with unreacted iodate ion; b) filtering the slurry as obtained in step (a) to obtain iodate-exchanged synthetic hydrotalcite as a filter cake and filtrate containing alkali metal iodate and alkali metal hydroxide; c) washing the filter cake obtained in step (b) with distilled water and mixing the washing with the filtrate obtained in step (b); d) making use of the filtrate in the solution of step (b) through a reaction with iodine crystals to obtain an aqueous solution of iodide and iodate salts; e) subjecting the aqueous solution in step (d) to electrochemical oxidation in a two-compartment electrochemical membrane cell to convert alkali metal iodide into alkali metal iodate; and f) recycling the solution obtained in step (e) in step (a), thus resulting in zero effluent discharge.