Mr. J. Brown on the Products of the Soda Manufacture. S3 



This salt is then introduced into a reverberatory or car- 

 bonating furnace, where it is strongly heated. In this process 

 the sulphuret of sodium is converted into sulphate of soda, 

 and part of the hydrate of soda into carbonate. The salt 

 when removed from the furnace is ready for the market. In 

 Newcastle and some other places it is dissolved and carbo- 

 nated again, and when thus manufactured it contains less caustic 

 soda. 



Soda-ash thus prepared contains from 48 to 53 per cent, of 

 available alkali, that is, alkali combined with carbonic acid 

 and water, and yielded on analysis, — 



99-496 100-341 100-00 



IV. Formation and Analysis of Carbonate of Soda. 



The next stage of the process which comes under our con- 

 sideration is the carbonate of soda process. 



The carbonate of soda balls are lixiviated with water in the 

 same way as in the manufacture of soda-ash. The liquor from 

 the settler is pumped up into a pan, where it is evaporated till 

 it becomes nearly dry ; it is then taken out of the pan in co- 

 landers, thrown up in a heap and allowed to drain. The 

 sulphuret of sodium and caustic soda soon deliquesce and 

 drain out from the salt. 



This salt, after drying at 212°, gave when analysed, — 



Phil. Mas. S. 3. Vol. 34. No. 226. Jan. 1849. D 



