UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 312 



Contribution from the Bureau of Soils 

 MILTON WHITNEY, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



November 5, 1915 



PHOSPHATE ROCK AND METHODS 



PROPOSED FOR ITS UTILIZATION 



AS A FERTILIZER 



By 



WILLIAM H. WAGGAMAN and WILLIAM H. FEY 



CONTENTS 



Page 



Introduction 1 



Phosphate Deposits of the United States 3 

 Forms in wiiich Phosphoric Acid is Ap- 

 plied to Soils 8 



Processes for Treating Phosphate Rock 

 in the Manufacture of Phosphoric Acid 



and Phosphatic Fertilizers 8 



Processes for the Production of Phos- 

 phoric Acid or Soluble Phosphates by 

 Combined Heating and Acid Treatment 1 2 

 Double Decomposition by Means of an 



Alkali, an Alkali Salt, or Alkaline Earth . 12 

 Processes to be Used in Connection 

 with the Iron and Steel Industries . . 14 



Processes in which the Phosphorus or 

 Phosphoric Acid is Volatilized ... 



Processes Dealing with the Production 

 of Two or More Fertilizer Elements . 



Processes Dealing with the Production 

 of Available Phosphates by Electrolysis 



Processes for the Enrichment of Phos- 

 phates 



Mechanical Treatment of Phosphates . 



Miscellaneous Processes for the Produc- 

 tion of Available Phosphates .... 



Appendix: Classified Tabular List of 

 Patented Processes 



18 



19 



20 



20 



WASHINGTON 

 GOVERNMENT PBINTINa OFFICE 



191(5 



