169 



Ordinary Meeting, January 21st, 1862. 



E. W. BiNNEY, F.R.S., F.G.S., Vice-President, in the Chair. 



William Arthur Darbishire, Esq., B.A., was elected an 

 Ordinary Member of the Society. 



A Communication, " On the Action of Nitrate of Sodium 

 on Sulphide of Sodium at Different Temperatures," by Dr. 

 Ph. Pauli, Union Alkali Works, St. Helens, Lancashire, 

 was read by Professor Roscoe. 



The mother liquor obtained in the manufacture of soda 

 ash contains, as is well known, large quantities of sulphide 

 of sodium. In order to oxidise that compound, nitrate of 

 sodium is used. As long as the boiling point of the liquid 

 is betw^een 280 — 290° F., the sulphide is quietly oxidised to 

 sulphate, nitrite of sodium being formed. 



But if the nitrate is added when the temperature of the 

 boiling liquid is about 310° F., a violent evolution of ammonia 

 takes place, according to the following equation — 



2NaS + NaNO 6 + 4H0 = 2NaS04 + NaH02 + NH3 



As the liquor contains a large amount of sulphide, the 

 quantity of ammonia is so considerable that it may prove 

 worth while to connect the evaporating pot with a tower 

 filled with coke, over which a stream of water or dilute acid 

 is running. 



If the nitrate be added when the liquor has been heated to 

 a temperature much above 310°, a violent evolution of pure 

 nitrogen occurs. 



o Na S + 4 N« NO 6 + 4 HO = 5 No SO 4 4- 4 Na O2 H + 4 N. 

 PfiOCEBDiNGs— Lit. & Phil. Society—No. 9.— Session 1861-62. 



