Salt, aka sodium chloride, is a low-priced commodity of prime significance for human consumption and as industrial raw material. In pre-independent India taxes at the commodity caused an upswell of discontent, which eventually led to freedom from colonial rule. While dietary deficiency in salt may be life-threatening (as seafarers of yesteryears nicely knew), its high stage in processed foods is criticized for lots physical ills.
Salt is an essential industrial raw material, utilize for production of industrial chemicals, especially soda ash and caustic soda. India is a leading exporter of salt, although not a maker of markets.
Salt manufacture
Production of salt in its different forms – edible, vacuum, industrial, table salt, fortified with iodine – helps lots of households, especially in coastal Gujarat and Tamil Nadu, and in Rajasthan, which 3 States together account for 95% of all salt manufacturing and almost all exports. Nearly 3-quarters of salt comes from simply 6 areas of Gujarat – Kutch, Jamnagar, Saurashtra, Little Rann of Kutch, South Gujarat and Maliya. Much is manufacture in the unorganized sector by means of solar evaporation of seawater the use of rudimentary, labour-extensive techniques. The industry gives direct employment to nearly 0.1-mn persons, operating in 12,000 salt works, of which only 400 are massive-scale.
Salt production is simple and starts with constructing embankments for storing salt water quickly after the monsoon recedes. In 2-3 months, the water dries up and salt forms a thick layer. The pinnacle layer, being the purest, is used for safe to eat purposes, even as the remaining layers are cleaned and sent for industrial use.
The principal impurities in salt are divalent ions – specifically, calcium, magnesium and sulphate – and need to be eliminated to be used in the chlor-alkali industry. Over the last decade, there was good improvement within the quality of salt manufacturing, catalysed through the efforts of the Bhavnagar-based totally Central Salt and Marine Chemicals Research Institute (CSMCRI), a CSIR lab. While the quality of Indian salt was once stated to underneath that from Australia and Mexico, these days salt of over 99.5% purity may be gained directly in solar salt fields even without mechanical washing.
Significant procedures have also been made in utilization of sea bittern (the brine left after recovery of salt) as a resource for bulk marine chemical compounds, especially bromine. Combined techniques in which salt manufacturing is accompanied with the aid of recovery of sulphate of potash and magnesia from kainite-type blended salt (composite salt with chlorides & sulphates) has also been evolved.
Global salt marketplace
The worldwide market for salt is about 350-mt, and China is the most largest user with 36% share, observed by North America, Western Europe and India. About 60% of salt requirement is within the chemical industry (specially chlor-alkali), followed by requirement for deicing (13%) and within the food industry (11%). About 50-mt of salt is traded across the seas and is restrained by the reality that the cost of transportation is corresponding to the value of salt. Australia, India and China are the main exporters, whilst the USA and Asian markets (China, South Korea, Japan, Taiwan and Indonesia) are main importers. While North American chlor-alkali manufacturers have get access to captive or merchant brine sources of salt, about half of European manufacturers purchase it within the merchant marketplace.
To be competitive in worldwide markets salt manufacturers must to have a low production value function and, just as essentially, access to a seaport from where the material may be shipped. Large clients also need to be near ports, and that is the case, for instance, with caustic soda manufacturers in coastal China, who collectively account for 20% of the country’s manufacturing.
With much of the new chlor-alkali capacity in the world anticipated to come up in Asia, the significance of this salt-importing marketplace will increase. Salt capability additions in Australia, the Middle East (Oman, Saudi Arabia, Qatar), and to some extent India and Pakistan will make sure there’s sufficient available to meet the incremental requirement.
Raising productiveness
India is the third largest manufacturer of salt globally with manufacturing of around 30.8-mt in FY23. About a third of the salt consumed is used for industrial purposes, broadly speaking in the production of caustic soda and soda ash. Exports show enormous volatility and reached 11.8-mt in FY23.
With the chlor-alkali sector predicted to develop quicker than its historical pace, there are fears that salt supply could become a crunch. With the area underneath salt manufacturing not going to enlarge significantly, a much will be based upon increasing productivity. This is dependent on several elements, a few beyond the control of manufacturers – the number of wet days; density of the seawater; sort of soil; price of evaporation (that is depending on the intensity of sun radiation); humidity; and wind pace. But industry experts reckon salt productivity can be increased to 90-100 tons/acre from the present 60 tons/acre, with the proper technological interventions and policy aid.
Improving quality
While the earlier technologies for caustic soda – using mercury or diaphragm cells – did not require high quality salt, that changed with the advent of membrane technology, which India’s industry enthusiastically followed. In these plants, the quality of salt no longer determine the efficiency of the overall procedure but, importantly, the lifespan of the expensive, imported membranes. Important parameters that membrane-qulaity salt needs to match include purity of sodium chloride, and the amounts of calcium, magnesium, sulphate, iodide, bromide, and total organic carbon (TOC). The chlor-alkali industry also specifies limits (in part per million) for elements like chromium, barium and aluminium. While a few upgrading of the brine is done through caustic soda units prior to pumping into electrolytic cells, it falls upon the salt industry to better its quality.
There are two stages of efforts taken to advance brine quality by salt producers: pre- and post-harvesting. The former includes the quality & management of brines and the processes adopted, while the latter includes mechanical washing and chemical treatments. A aggregate of both is needed to ensure the quality desired.
An essential element is to optimize methods to account for differences in brine quality – not just among States, but even within one. For example, brines in inland Rajasthan have better ranges of insolubles, sulphate, TOC, iodide, bromide, carbonates and bicarbonates, compared to ones from Gujarat, making the former unsuitable for caustic soda making.
Diversifying product slate
Salt producers ought to observe opportunities in higher value products inclusive of pharmaceutical grade salt – requirement for that is globally on the increase and supplier base is restricted to simplest about 25 manufacturers. Dialysis is the most crucial application for this top product, accounting for 75% of its requirement. India’s important salt players (and others) have also built giant sizeable for bromine, and similarly value addition opportunities are available downstream. The global requirement for bromine is growing at a CAGR of 4%, with Asia-Pacific growing at nearly twice the tempo. While the United States and Israel lead in bromine manufacturing, India is not a long way at the back of and has the capability to move up to number 2 spot, if not pole position, in the following couple of years.
The prospects for deliver of pure brine from salt works by pipelines to the chlor-alkali industry, in preference to transporting solid salt to be transformed into brine at the latter’s facilities, is also worthy of consideration.
Challenges ahead
In coming years, the salt industry will need to adapt to the changes added about by a warming planet. Changing weather patterns in Kutch and Bhavnagar, for example, have decreased the number of sunny days, and in a few years the number of days for salt harvesting has halved from 240 to 120. Combined with more rains, this has brought about lower overall productivity. More and severe cyclones are also landing in Gujarat.
If the Indian salt industry is to enhance its competitiveness in worldwide markets, it will need access to better infrastructure – within the form of roads, railways and ports.
The industry will even benefit from a modernization of rules and guidelines governing it. Many are archaic and framed at some point of British rule. The Indian Salt Manufacturers Association has been demanding the classification of salt as a seasonal agricultural product, in place of a mining product, as just 0.5% of total output comes from mining and the balance is produced from seawater or sub-soil water. There is merit to this demand.
