Chemicals Based Technologies - Bromine from Sea Water

Introduction

Bromine is widely distributed in nature, but in relatively small proportions. Bromine and bromo-compounds have wide range of uses in chemical and other uses. It is used for the manufacture of dye intermediate & dye stuffs, drugs & pharmaceutical products, photography chemicals, insecticides, fuming agents, antiknock gasoline, fire retardants, in textile industry and in oil exploration. It is also used in controlling microbes and algae in swimming pools.

The bromine available for extraction occurs as bromide in the ocean, in salt lakes and in brine or saline deposits left by evaporation of such waters by solar heat. Sea bitterns, the left over concentrated solution after the crystallizing out of salt from the sea water, are very reach in bromine and offers a good raw material for the manufacture of bromine. Sea bittern having at least 2.2 gm/lit bromine , is most suitable for the manufacture of bromine. The technology for manufacture of bromine has been developed at Central Salt and Marine Chemical Research Institute, Bhavnagar, India and the technology has been licensed to 9 salt manufacturers and five of them are in production. The capacity utilization of these plants during the last ten years was noticed to be varying between 30 % to 70 % and their total production always remained far below the demand of bromine in the country. The total demand of bromine for the year 2000 AD has been projected to be 700- 800 tonnes and to meet the requirement of bromine in the country ,the production capacity of the country has to be increased by at least 60 %. Therefore the production of bromine offers a good prospects to those entrepreneurs who has access to sea bittern.

Process

The 30o Be' bittern from the reservoirs is taken in sump tank and then fed to the chlorinating tower. After perchlorination, the cold bitterns is preheated by hot recycle brine and the fed at the top of a stripping tower wherein steam is introduced at the bottom to further heat the bittern to boiling point and strip the bromine liberated by chlorine. Sulfuric acid is also added to the tower to facilitate stripping of bromine. The liberated bromine with excess steam is passed through the two stage condenser to separate steam and uncondensed bromine and chlorine gas mixture is scrubbed in the chlorinating tower. The crude bromine is separated from water in gravity separator and further purified by fractional distillation and passing through sulfuric acid column. The water condensed overhead of stripping tower and the impure gas emerging from the distillation column are recycled. The debrominated effluent brine is treated with caustic soda and is used for pre-heating chlorinated bittern.

Plant Parameters

Raw Material

Utilities (Per Tonne of Product)

Plant & Machinery

For further information please contact :

National Research Development Corporation
( A Government of India Enterprise )
20-22, Zamroodhpur Community Center
Kailash Colony Extension
New Delhi 110 048. India
Tel: 91-11-26419904, 26417821, 26480767, 26432627
Fax: 011-26231877, 26460506, 26478010
Website: www.nrdcindia.com

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