Free flowing 100-500 micrometer size spherical crystals of common salt and process for preparation thereof

A process of preparing free flowing spherical shaped crystals of common salt without using any habit modifier, comprising:

• (a) charging saturated brine optionally along with an anti-solvent into a thermally insulated stainless steel vessel fitted with heating tape on the external wall of the vessel and with a mechanical stirrer of appropriate dimension and configurations with a stirring rate ranging between 200-275 r.p.m;
• (b) raising the temperature of the brine as obtained from step (a) gradually while stirring up to the pre-set point in the range of 40° C. - 80° C.,
• (c) holding the temperature of the brine as obtained from step (b) at temperature of 58±2° C. and allowing the brine to evaporate under mechanical stirring at speed of 220±10r.p.m;
• (d) discharging the salt slurry as obtained from step (c) from the bottom when the pre-set point of evaporation is being reached and the brine volume being reduced to 25-35% (v/v) of the initial volume taken;
• (e) charging the slurry as obtained from step (d) into a centrifuge followed by washing the charged slurry with a spray of saturated solution of sodium chloride;
• (f) charging the wet salt as obtained from step (e) in a shallow stainless steel tray, followed by drying in the open sun to reduce the moisture content up to 0.5% (w/w) while minimizing agglomeration;
• (g) sieving the dry salt as obtained from step (f) through progressively finer sieves ranging between 35-60 mesh size to fractionate the salt crystals so as to attain the desired size distribution;
• and
• (h) recycling the residual glycine solution in the subsequent batches after topping up with additional glycine if required.