POTASSIC MANURES 117 



merit, with about 1 part of calcium chloride 

 and about 2 to 3 parts of lime. When this pro- 

 portion of the reagents is used, considerable 

 variation in the temperature of ignition will 

 give the same results, and almost the entire 

 amount of the potash is rendered soluble at 

 a temperature below the melting-point of po- 

 tassium chloride. 



The results obtained on igniting feldspar 

 with lime and sodium chloride are in agreement 

 with those published by Rhodin, the author 

 of the patent covering this process, who only 

 claimed an extraction of about 14 per cent of 

 the potash in the feldspar when using the pro- 

 portion of the reagents stated in the patent. It 

 was pointed out, however, that a more favorable 

 result was obtained by using a larger amount 

 of salt with a smaller amount of lime. Thus, 

 when 100 parts of feldspar were ignited to 900 

 C. with 40 parts of salt, about 70 per cent of the 

 potash in the feldspar became soluble, which 

 agrees with the values given for approximately 

 this proportion of the reagents. 



Unless a large excess of calcium chloride 

 is used, when ignited with feldspar and lime, 

 no vitrification takes place on heating to a tem- 

 perature up to 1050 C. The ignited mass re- 

 mains in the form of a powder, and consequently 

 the soluble material present can be readily 

 leached out without the necessity of any previ- 

 ous grinding of the mass. The same statements 



