Precipitated Phosphate 



It is sometimes mixed with superphosphate, but 

 we do not recommend the mixture, because generally 

 it only represents a very small proportion of super- 

 phosphate to the bone flour. 



It is better to transform it mto superphosphate 

 of bone by means of sulphuric acid, when it con- 

 stitutes a phosphatic manure of the finest quality. 

 It is sometimes adulterated by the addition of 

 gypsum, mineral phosphates, or marl. 



Bone Ashes. 



Bone ashes come from the Argentine, and are 

 obtained by burning bones which are found there, 

 sometimes m very large beds. They contain on an 

 average 72 to 73 per cent, of tribasic phosphate. 

 In this capacity they ought only to be employed 

 on acid lands and should never be expensive. 

 Transformed into superphosphates, they make a 

 good manure, and should then be bought according 

 to the unit of soluble phosphoric acid. They 

 should always be bought on analysis, because they 

 generally contain many impurities. 



Precipitated Phosphate. 



This is a product obtamed by precipitating with 

 milk of lime the phosphate produced by treating 

 bones with hydrochloric acid. It is a fine white 

 powder containing about 40 per cent, phosphoric 

 acid. The process which is carried on in connection 

 with the gelatine industry is as follows. The mineral 

 matter of the bones is solubilised by means of a 

 considerable excess of hydrochloric acid. Little 

 by little milk of lime is added to this solution and 



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