FROM ORTHOCLASE FELDSPAR WHYTE 147 



the potassium aluminum sulphates obtained in solution are 

 separated by crystallization. A recovery of 90-92 per cent, of 

 the potash contained in the felspar is claimed. 



It is claimed that most of these methods give satisfactory 

 results, but the cost of extraction is too great to permit of com- 

 petition with the industries of Europe. 



The future then of the potash industry on the American Con- 

 tinent, depends on the discovery and development of an econ- 

 omical process of separation. 



Method. — In a foregoing paragraph several methods for de- 

 composing felspar are outlined, but the decisive objection to 

 these is their cost of operation, A cheap method is still being 

 sought. Rocks are being decomposed continuously in nature 

 in the general process of change and denudation. Statements of 

 geologists on this matter will be of interest. The Encyclopedia 

 Britannica says "It has been supposed that the alteration 

 of the granite or felspar has been effected mainly by meteoric 

 agencies, the carbonic acid having decomposed the alkaline 

 silicate of the felspar, whilst the aluminous silicate assumes a 

 hydrated condition and forms kaolin." It may be mentioned 

 that the formation of kaolin and of potash is brought about by 

 the same operation. 



With regard to kaolinization A. W. Graham says: — "The 

 ordinary effect of the atmospheric moisture on the rocks is the 

 attack upon the felspars producing kaolin or clay. This com- 

 monly takes place in the presence of CO2 . The formula for the 

 alteration of orthoclase felspar into kaolin, quartz, and potash 

 being 



2K Al Si3 Os + 2H2 O + CO2 -^H4 AI2 Si2 O9 +4Si02 +K3 CO3 



Bulletin 695, U. S. Geological Survey states, in effect, that 

 felspathic decay is not formed by ordinary weathering but by the 

 operation of thermal waters and gaseous emanations, and car- 

 bonated waters. While all these processes and others are oper- 

 ative yet the chief chemical activity is due to carbonic acid. 



The most important gaseous emanation referred to is probably 

 SO2 . There is a deposit of potash in Hungary supposed to have 

 been derived from orthoclase by the action of sulphurous eman- 

 ations of a neighboring volcano. 



Though nature works by means of these simple agents yet 

 progress is very slow. Many chemical reactions can be hastened 



