154 



STASSFUET SALTS 



were worked as a source of potash compounds, and now enormous 

 quantities are annually raised and furnish almost all the potash required 

 in the arts as well as in agriculture. 



The chief compounds are classed under the following mineralogical 



names :- 



Sylvine, KC1. 



Sylvinite, a mixture of sylvine, rock-salt and kainite. 

 Carnallite, MgCl 3 .KC1.6H a O. 

 Schonite (Picromerite), MgSO 4 .K 2 SO 4 ,6H 2 O. 

 Kieserite, MgSO 4 .H 2 O (mixed with carnallite). 

 Kainite, MgS0 4 .KC1.3H 2 O, or MgSO 4 .K 2 S0 4 .MgCl .6H 2 O. 

 Polyhalite, K 2 SO 4 .2CaSO 4 .MgSO 4 .H 2 O. 



The substances do not occur in the pure form indicated by these 

 formulae, but are more or less mixed with each other and especially 

 with rock-salt. Carnallite is, by far, the most abundant. 



The output of Stassfurt salts is now regulated by a syndicate, who 

 limit the production and fix the prices of the various salts. 



In 1898 the quantities, in tons, produced and sent out to the various 

 countries were as follows : 



Of the 70,877 tons of chloride used in .Germany only about 1528 

 tons were employed in agriculture, the rest being used as the raw 

 material for the production of other potash salts. Of the 107,107 tons 

 exported, however, about 64,000 tons were employed for agricultural 

 purposes, the extra cost of this material over the raw products, kainite, 

 etc., being compensated by the greater cheapness of its transport, owing 

 to its high potassium content. The same is true of potassium sulphate, 

 which in Germany is chiefly used in the preparation of alum, not more 

 than a third of the quantity given in the table being used as a fertiliser, 

 while of that exported more than seven-eighths of the total is employed 

 in agriculture. 1 



1 Sammel-Ausstellung der Deutschen Chemischeu Industrie, Paris Exhibition, 

 1900. 



