KAINIT 



COMPOSITION OF SALTS CONTAINING CHIX>RIDS. 



495 



Potash Manure Salts. 



421. Detailed Description of the Principal Salts Used in the 

 Manufacture of Fertilizers. Some of the salts of potash such as 

 kainit, are used as fertilizers just as they are taken from the mine. 

 Others, such as carnallit and sylvinit, may be used directly as fer- 

 tilizer, but more commonly are subjected to a process of manu- 

 facture or concentration whereby other compounds are produced. 

 A description of the more important salts follows. 



422. Kainit. The most important of the natural salts of potash 

 for fertilizing purposes is the mixture known as kainit. It is 

 composed in a pure state of a molecule each of potassium, sul- 

 fate, magnesium sulfate, magnesium chlorid, and water. Chem- 

 ically it is represented by the symbols : 



K 2 SO 4 .MgSO 4 .MgCl 2 .H 2 O. Its theoretical percentage of pot- 

 ash (K 2 O), oxygen 1 6, is 23.2. 



Pure kainit, however, is never found in commerce. It is mixed 

 naturally as it comes from the mines with common salt, potassium 

 chlorid, gypsum, and other bodies. The content of potash in the 

 commercial salt is, therefore, only a little more than half that of 

 the pure mineral. In general it may be taken at 12.5 per cent., 

 of which more than one per cent, is derived from the potassium 

 chlorid present. The following analysis given by Maercker may 

 be regarded as typical: 4 



4 Die Kalidiingung, 2nd Edition, 1893 : 5. 



