been rendered soluble on heating a given amount of feldspar at 

 1,000-1,050 'C. with varying amounts of calcium carbonate and 

 calcium chloride, and with calcium carbonate and sodium chloride. 

 The feldspar used in these experiments was ground to pass a 100- 

 mesh sieve and contained 13.72 per cent of K 2 O, and 2.18 per cent of 

 Na,O. 



Table II. Showing percentages of alkalies rendered soluble when feldspar is 

 ignited with varying amounts of calcium carbonate and calcium chloride, and 

 with calcium carbonate and sodium chloride. 



In these experiments the results show that while a considerable 

 portion of the potash was rendered available when using approxi- 

 mately the proportions of the reagents stated in the patents, the 

 total potash in the feldspar was not rendered soluble in this way at 

 the temperature specified. Thus, when 1 part of feldspar is ignited 

 with 1 part of calcium carbonate and 0.25 part of calcium chloride, 

 which is 0.05 part in excess of that equivalent to the alkalies in the 

 feldspar, only about 60 per cent of the potash in the feldspar is 

 rendered soluble. Increasing the proportions of calcium carbonate 

 and calcium chloride used produces a comparatively small increase in 

 the amount of soluble potash obtained, and complete decomposition 

 of the feldspar only takes place when one part is ignited, under the 

 conditions of the experiment, with about 1 part of calcium chloride 

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

 sium chloride. 



The results obtained on igniting feldspar with lime and sodium 

 chloride are in agreement with those published by Khodin, 1 the 



. Soc. Chem. Ind., 20, 439 (1901). 



[Cir. 71] 



