The Phosphates of America. 133 



really is can easily be shown by a few figures which, while not pre- 

 sented as the actual cost at which large and well-situated manu- 

 facturers could produce it, will suffice for purposes of illustration. 



Commencing with the cost of phosphoric acid and assuming 

 the factory to be located at a point within easy access by rail or 

 by water, or both, we may calculate that 



1 ton of 2000 pounds mineral phosphate, containing fifty 



to sixty per cent, phosphate of lime. will cost $4.00 



Grinding same to a fineness of 70 to 80 mesh. .. " 1.50 



2130 pounds chamber sulphuric acid of 50 B. at. say, 



$7.00 per ton will cost 7.50 



Labor of mixing and filtering, wear and tear, etc., cal- 

 culated at the rate of, say, $1 per gross ton of raw 

 material handled will cost 2.00 



Concentration, labor, wear and tear of plant, calculated 



at $1 per gross ton of raw material will cost 2.00 



Total net cost of producing, say, 1000 pounds 



of 45 B. phosphoric acid $17.00 



Cost of the 45 B. phosphoric acid per ton of 



2000 pounds $34.00 



Passing now to the manufacture of high-grade superphosphate 

 by decomposing the mineral phosphates with this acid instead of 

 with chamber sulphuric acid, we shall find that it works out thus: 



1 ton mineral phosphate, containing seventy-five to 

 eighty per cent, tribasic phosphate, and of about the 

 general composition shown in the examples selected 



for former calculations will cost $14.50 



Grinding same to 70 or 80 mesh " 1.50 



1 ton phosphoric acid of 45 B " 34.00 



Cost of mixing, manipulating, drying, pulverizing and 

 bagging the finished material, calculated at $2 

 per ton of material used. 5.00 



$55.00 



The net product of the mixture after allowing fifteen 

 per cent, for loss, by evaporation and in manufact- 

 ure, will be, say, thirty-four hundred pounds. It 

 will contain fifteen hundred and thirty pounds of 

 phosphoric anhydride (P 2 O 5 ) and costs $55.00 



Its cost per ton, ready for market, and containing forty- 

 five per cent, of mixed water-soluble and citrate- 

 soluble phosphoric anhydride will therefore be $32.50 



Or a little over 3^ cents per pound of phosphoric anhydride. 



