UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1179 
Washington, D. C. 
December, 1923 
INVESTIGATIONS OF THE MANUFACTURE OF PHOSPHORIC 
ACID BY THE VOLATILIZATION PROCESS 
WILLIAM H. WAGGAMAN, Scientist in Investigation of Fertilizer Resources; HENRY W.EASTERWOOD 
Chemist, and THOMAS B. TURLEY, Operation Engineer, Investigation of 
Fertilizer Resources. Bureau of Soils 
CONTENTS 
Page 
introduction 1 
Principles Involved in the Volatilization Process 2 
Advantages of the Volatilization Process 4 
Review of Methods for Producing Phosphorus and Phosphoric Add b; Volatilization 6 
The Use of the Electric Furnace in the Volatilization of Phosphoric Acid 9 
Coftrefl Electrical Precipitator . . . . , 10 
Larger Scale Experiments 11 
Electric Smelting of Mine-run Phosphates 13 
Theoretical Heat Balances ' 17 
The Use of the Fuel Furnace in the Volatilization of Phosphoric Acid 19 
Comparative Cost of the Thermal Unit Furnished by Electric Power and Fuel 20 
Preliminary Laboratory Experiments 24 
The Briquelting of Mineral Phosphates ,~~. . . 27 
Effect of High Temperatures on Various Briquetted Mixtures 32 
Larger Scale Experiments 37 
Present Furnace Equipment and Latest Results 39 
Discussion of Experimental Results 45 
Estimated Cost of Production 46 
Summary and Conclusions 48 
WASHINGTON 
GOTERNMENT PRINTING OFFICE 
1923 
