116 MANUFACTURE OF FERTILIZING MATERIALS 



of water and recovered from the solution, or 

 utilized there in any preferred way. 



From a comparative study which was made of 

 these patents it does not appear that the use 

 of sodium chloride has any advantage over 

 calcium chloride. The latter is a by-product 

 obtained in large quantities in the manufacture 

 of sodium carbonate, and is somewhat more ef- 

 fective than the former in bringing about com- 

 plete decomposition of the feldspar, but when 

 limited amounts of 'the reagents are used more 

 potash is rendered soluble with the use of sodium 

 chloride than with calcium chloride. 



In these experiments the results show that 

 while a considerable portion of the potash was 

 rendered available when using approximately 

 the proportions of the reagents stated in the pat- 

 ents the total potash in the feldspar was not 

 rendered soluble in this way at the temperature 

 specified. Thus, when 1 part of the 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 alkalis 

 in the feldspar, only about 60 per cent of the 

 potash in the feldspar is rendered soluble. In- 

 creasing the proportions of calcium carbonate 

 and calcium chloride used produces a compara- 

 tively 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 experi- 



