295 COTTER: SODA INDUSTRY OF SIND. 



According to Martin, Smith, and Milsom's Manual, 1 14J- tons 

 of coal are required to calcine every 100 tons of soda-ash produced 

 from bicarbonate of soda. 



Now 100 parts of trona correspond to 70-3 parts of soda-asb, 



according to the equation : — 



2Na 2 C0 3 , SNaHCO* 4H ft O-3Na a OO, +r>H„0 +OO r 

 452: 318 



that is 38-7 maunds of trona=27-2 maunds, or 1 ton, of soda-ash. 



That is for 3,870 maunds of trona or 100 tons of soda-ash, about 

 14*5 tons of coal are required, or 394-4 maunds, assuming that a 

 nearly similar quantity is required for trona as for bicarbonate. 



The cost of recovery of the trona from the bitterns is impossible 

 to estimate. I may mention however that at the Salt-Gardens at 

 Maurypur near Karachi, the recovery of salt from sea-water costs 

 in the present time (1918-19) of high prices, five annas per maund 

 according to information received from Mr. Thurley. The cost of 

 recovery of trona is of course a very different matter, but in general 

 principle the operations are similar, consisting as they do of the 

 concentration by solar evaporation of dilute solutions. 



The price of soda-ash produced artificially is Rs. 5-11 per cwt. 

 or about Rs. 4-5 per maund. The soda-ash produced from natural 

 trona would be less pure than the artificial article ; I do not think 

 one could aim at a purity of much over 90 per cent. In conse- 

 quence it could not command so high a price. Nevertheless even 

 if it fetched only Rs. 3-8 per maund, it seems possible that there 

 might be a final margin of profit sufficient to make it worth while to 

 develop^ the industry. 



Whatever be the future of the soda industry of Sind, it would 

 ^ . . certainly be advisable to work at least the 



Conclusion. . . J . 



existing dnands m a scientific manner, having 



regard to the principles of chemistry, and applying a knowledge of 



the fractional crystallisation of u triple M waters to practical 



purposes in the process of recovery of the trona. 



1 "The Salt and Alkali "Industry", by G. Martin, S. Smith, and F. Milsom, 1010, 

 y, 71. 



