282 AGRICULTURAL ANALYSIS 



such quantity as to interfere with the subsequent drying, grind- 

 ing, and marketing of the acid phosphate. 



For convenience, the following table may be used for calcula- 

 ting the quantity of oil of vitriol needed for the entire decomposi- 

 tion of each unit of weight of material noted. 



ONE PART BY WEIGHT OF EACH SUBSTANCE BELOW REQUIRES : 



Sulfunc Acid by Same Unit of Weight. 



At 48 B. At 50 B. At 52 B. At 54 B. At 55 B. 



Tricalcium phosphate I-59Q 1.517 1.446 1.382 1.352 



Iron phosphate 1.630 1.558 1.485 1.420 1.390 



Aluminum phosphate 2.025 I -93 T "839 1.756 1.721 



Calcium carbonate 1.640 1.565 1-495 1.428 1.411 



Calcium fluor id 2.006 2.010 1.916 1.830 1-794 



Magnesium carbonate 1.940 1.860 1-775 1.690 1.660 



Example. Suppose for example a phosphate of the following 

 composition is to be treated with sulfuric acid; viz., 89 



Moisture and organic matter 4.00 per cent. 



Calcium phosphate 55-oo " 



Calcium carbonate 3.00 " 



Iron and aluminum phosphate nearly all alumina 6.50 " 



Magnesium carbonate 0.75 " 



Calcium fluorid 2.25 " 



Insoluble 28.00 " 



Using sulfuric acid of 50 B., the following quantities will be 

 required for the weights mentioned: 



Kilos of acid required. 



Calcium phosphate, fifty -five kilos 83.44 



" carbonate, three and a half kilos 5.48 



" fluorid, two and a quarter " 4.52 



Aluminum and iron phosphate, six and a half kilos 12.55 



Magnesium carbonate, three-quarters of a kilo 1.40 



Total 68 kilos 107.39 



Since only a partial decomposition is attained in actual manu- 

 facture the quantity of 50 Beaume acid required is often less than 

 the weight of phosphate treated. 



243. Phosphoric Acid Superphosphates. If a mineral phosphate 

 be decomposed by free phosphoric acid in place of sulfuric acid, 

 the resulting compound will contain about three times as much 

 39 Wyatt, Phosphates of America, 4th Edition, 1892 ; 128. 



