Common salt after extraction from the sea, lake or underground deposits typically consist of crude lumps or granules which contain, in addition to sodium chloride, sand, mud, moisture, other salts and organic matter. This crude salt is generally off-white or yellowish-brown in colour, This salt is unhygienic, and hence poses health hazards if taken in this form. Further, this salt provides challenges to salt iodization program.
The success of salt iodization depends primarily on the quality of salt to be iodized. Moisture and impurities in salt tend to destroy its iodine content. So mixing iodine compound with salt is not the solution. Salt has to be refined and dried to enable it to retain the iodine content put into it. So refining and drying ensure.
Iodine content in edible salt
Purity and Hygiene
Convenience in usage as it becomes free flowing
Good visual appearance because of dryness and whiteness
Because of the above reasons, the business of refining and iodizing of common salt is growing all over world with an accelerated pace.
The concept of salt being used as a carrier for imparting iodine is being extended to impart other micro nutrients and tasty flavors & ingredients. Only refined and dryed salt is capable of carrying and retaining such ingredients and flavours.
Refining of salt is also essential for its use as raw material in industries. Use of dried refined salt in place of dirty and unhygienic solar salt in industries, like, food processing, cattle feed, oil drilling, fish processing, textile, detergent, dyes, chemicals and others, enhances quality and appearance of their products.
Washed Raw salt from your Raw salt washery stock pile will be fed into Vertical Bucket Elevator through a vibratory feeder. Vertical Bucket Elevator (VBE), will discharge salt into a Wet Mill. Crushed salt is subjected to upgradation in a multi-stage cleansing system which comprises of a series of special design vessels, like, Elutriation Tank, Washing Tank, Thickener, etc. These are integrated with devices for continuous reduction in load of sand and grit in the salt slurry. The lighter insolubles drift away with the over flows. These cause improvement in both the physical and chemical attributes of common salt. Salt, thus upgraded, is then subjected to centrifuging and blending with crystal habitat modifiers and Potassium Iodate solution. The blended salt is then fed in a continuous type Fluidized Bed Dryer. The feed material and hot air come in contact with each other and drying takes place. The exhaust air carries the moisture removed from the product away. Dried product is collected at the bottom of the other end of the FBD. The exhaust gas is passed through cyclone separator for recovery of salt fines. Fine salt is separated and collected at the bottom.
Dried salt is graded in Vibro Sieving machine. Oversize crystals are crushed in Pin-mill or in roller crusher as per the requirement and routed back in the system through the fluidized bed dryer. The salt crystal having sizes mostly between (-) 850 to (+) 150 microns are mixed in a Blender with suitable quantity of additives including a free flowing agent and conveyed by means of Screw Conveyors to packaging machines for being packed in consumer packs. The crystal size of (-) 150 microns, collected from the dryer cyclone, are packed in laminated HDPE bags in 25 / 50 kgs lot. Magnetic separators are provided at various stages of processing for removal of iron particles.
The spent brine, collected after washing of salt is sent to settling pond where it is regenerated on removal from it the excess load of calcium, magnesium & insoluble impurities. The brine thus improved is used again for upgradation of the common salt