Council of Scientific and Industrial Research

Indrajit Mukhopadhyay

Pushpito Kumar Ghosh

Vadakke Puthoor Mohandas

Rahul Jasvantrai Sanghavi

Abdulhamid Usmanbhai Hamidani

Puthoor Mohandas Vadakke

Venkata Rama Krishna Sarma Susarla

Arvind Kumar

Jignesh Jasvantrai Shukla

Venkata Rama Susarla

The present invention provides spherical shaped crystals of common salt having size distribution in the range of 100-500 &#x3bc;m and a process for preparation of the said salt. The above mentioned size range is relevant for many important edible and non-edible applications of salt. The salt is demonstrated to have superior flow properties compared to the cubic counterpart. The free flow property of the salt can be further enhanced through surface treatment with additive such as glycine. The salt is produced by cost-effective mechanical means and such production is amenable to scale up.

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

The process of the invention deals with significant improvements in salt purity and whiteness brought about through treatment of brine with alum prior to charging into crystallizers for solar salt production. The improvements realized are partly on account of elimination of suspended impurities like gypsum and clayey matter in the brine, which may otherwise be carried along with the brine in the crystallizer and finally end up in the salt, and partly due to the improved crystal size and morphology that minimizes embedded impurities in the salt. Rain washing of the heaped salt has resulted in a salt with greatly reduced calcium and sulphate impurity levels hitherto not achieved in solar salt production. Alum treatment by the process of the invention requires no additional time or infrastructure and the cost of the treatment works out to &#x3c;3 U.S. cents per ton of salt. The process can be implemented in any solar salt works.

Process for the preparation of solar salt having high purity and whiteness

The process of the invention is an improvement over the existing process of producing salt of high purity from alum-treated brine disclosed recently in the prior art. More particularly, the invention rectifies the ratio of Cato Mgfrom a value &#x3c;1 to a value in the range of 2-3 desired by chlor-alkali and soda ash industries. The improved process involves the adjustment of pH of clarified brine with aqueous HCl so as to carry out salt crystallization at a pH of 6.5 instead of at the natural pH of 7. The pH adjustment reduces the Mgimpurity in salt while slightly raising the Caimpurity in the salt and thereby achieving the desired ratio.

Process for the preparation of common salt of high purity from brines in solar salt pans

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Bhavnagar, India

Indrajit Mukhopadhyay