Norton — Action of Sodium Thiosulphate, etc. 115 



Art. XII. — The Action of Sodium Thiosulphate on Solu- 

 tions of Metallic Salts at High Temperatures and Pres- 

 sures ; by John T. Norton, Jr. 



[Contributions from the Kent Chemical Laboratory of Tale University — C.J 



The use of sodium thiosulphate as a substitute for hydrogen 

 sulphide in effecting precipitations and its application in the 

 case of arsenic, antimony, copper and platinum was suggested 

 by Himly* before the middle of the present century. Thirteen 

 years later Vohlf and Slater,;); independently, drew attention 

 to this use of sodium thiosulphate and extended the investiga- 

 tion to salts of tin, mercury, silver, gold, lead, bismuth and 

 cadmium. Slater in addition studied the action of sodium 

 thiosulphate upon chromic acid, molybdates, ferrous and ferric 

 ferrocyanides, ferric sulphocyanicle and potassium perman- 

 ganate. Following out these lines, the precipitation of copper 

 together with arsenic and antimony by treating with sodium 

 thiosulphate the hot solution containing sulphuric acid and the 

 separation of these elements from tin, zinc, iron, nickel, cobalt 

 and manganese has been advocated by Westmoreland§ ; and 

 quite recently Faktor[| has studied the action of sodium thio- 

 sulphate upon neutral salts of several of the elements men- 

 tioned, as well as the modifying influence of ammonium chloride 

 and other salts upon the course of the reaction. 



Subsequently to the work of Himly, Vohl, and Slater, Chan- 

 cel*[ developed his well-known method for the precipitation of 

 aluminum as the hydroxide and its separation from salts of iron 

 by boiling with sodium thiosulphate the nearly neutral solu- 

 tion, containing the salts of aluminum and iron, at suitable 

 dilution ; and upon an extension of the principle of Chancel's 

 separation of aluminum from iron, Stromeyer*"* founded his 

 well-known processes for the separation of titanium and zir- 

 conium from iron. The latter process appears to be fairly 

 trustworthy ; but of Chancel's method, although it has 

 met with wide acceptance, it was shown by Wolcott Gibbs 

 very soon after its announcementtf that it fails to bring about 

 complete separation of alumina within a reasonable period of 

 boiling, and this result has been confirmed by Zimmerman, %% 

 who has shown that the boiling must be continued fifteen 

 hours in order to complete the precipitation of the alumina. 



* Ann. Chem. (Liebig), xliii, 150. f Ann. Chem. (Liebig), xcvi, 237. 



% Chemical Gazette, 1855, p. 369. £ Jour. Soc. Chem. Ind., v. r 51. 



I Centralblatt, 1900, ii. 20. 67, 239, 594. *|Compt. rend., xlvi, 987. 

 ** Ann. Chem. (Liebig), cxiii, 127. \\ Zeitschr. anal. Chem., iii, 389. 



JJInaug. Diss., Berlin, 1887. 



