Time 



Potash 



2 hrs. 



.132% 





.100% 



" 



.115% 



150 EXTRACTION OF POTASH 



Successive Treatment with CO2 

 Treatment 

 CO2 and Boiling, Atmos. Press., 



Certain deductions from these results are quite clear, while 

 others remain problematical. 



It seems that heat and agitation alone do not cause a measur- 

 able amount of decomposition, at least during a period of a few 

 hours. 



Considering the action of carbon dioxide it would appear at 

 first that the time factor, heat, and agitation make practically no 

 difference, the percentage of potash obtained being the same 

 with a variation of these agents. 



But when the preliminary experiment was made with a higher 

 pressure and intermittent boiling an increase of decomposition 

 was obtained, which suggested heat and pressure as being of 

 some importance. Accordingly the special piece of apparatus 

 previously described was procured, but the results were disap- 

 pointing. It is obvious that the pressure used had no effect, 

 and it was only when heat and agitation were employed that the 

 degree of disintegration was brought up to what might be termed 

 the normal amount. 



It was thought that if the felspar were sintered the crystalline 

 character of the mineral would be sufficiently destroyed to per- 

 mit of more decomposition. This was accordingly done, but 

 practically no change in the result was obtained. 



The idea was gradually being acquired that the sample of 

 orthoclase had previously undergone a certain degree of weather- 

 ing or alteration of some kind in consequence of which a small 

 percentage of the sample was subject to the action of carbon 

 dioxide while the rest was unaffected. To test this idea a series 

 of successive treatments was carried out. The sample was 

 treated for two hours at atmospheric pressure with heat and 

 agitation (boiling) and a continuous stream of carbon dioxide. 

 The residue was reground and the treatment repeated. Prac- 

 tically the same amount of decomposition was obtained each 

 time. This dispels the idea of prealteration and points to the 

 conclusion that the breaking down of the felspar is of a pro- 

 gressive nature. It may be mentioned here that on filtering 

 the reaction product a very fine clay light brown in color was 

 always left on the filter. The reason for its color is not apparent, 



