Contribution from the Bureau of Soils 
MILTON WHITNEY, Chief 
Washington, D.C. Vv November 5, 1915 
PHOSPHATE ROCK AND METHODS PROPOSED FOR 
ITS UTILIZATION AS A FERTILIZER. 
By Witu1am H. WaGGaman and Wituiam H. Fry. 
CONTENTS. 
; Page. Page. 
BENG HONE eee) oceanic. 52 J-+esee en 1 | Processes in which the phosphorus or phos- 
_ Phosphate deposits of the United States..... 3 phoric acid is volatilized................... 15 
_ Forms in which phosphoric acid is applied to Processes dealing with the production of two 
3ST, DSS eS ee ee 8 or more fertilizer elements 2... --22.-..- 22.2 17 
Processes for treating phosphate rock in the Processes dealing with the production of avail- 
_ manufacture of phosphoric acid and phos- able phosphates by electrolysis.....-...-.- 18 
mepRatic fertilizers... ..o..25- ssc oe... e222 ee 8 | Processes for the enrichment of phosphates. - 19 
_ Processes for the production of. phosphoric Mechanical treatment of phosphates .....-.- 20 
acid or soluble phosphates by combined Miscellaneous processes for the production of 
___ heating and acid treatment................ 12 availablesphosphatesss. ese sen ees 20 
_ Double decomposition by means of an alkali, Appendix: Classified tabular list of patented 
Ms an alkali salt, or alkaline earth............- 12 ROCOSSES 2c aspen Sone eee es ae eae 21 
_ Processes to be used in connection with the 
o-aron and steel industries......-...:.....-.- 14 
INTRODUCTION. 
_ The basis of nearly all mixed fertilizers is water-soluble or so-called 
“available” phosphoric acid, which is produced by submitting bones, 
“a mineral phosphate (apatite or phosphorite), or some other phos- 
phate-bearing substance to a treatment by which the constitution of 
the original body is materially changed. ; 
Our supply of bones is entirely inadequate to meet the present 
“demands of the fertilizer industry, while apatite has proved objection- 
| able because of the difficulty and expense of mining the mineral and 
‘on account of the quantity of fluorine which it contains. By far the 
reater part of the phosphate fertilizer is derived from phosphorites 
r amorphous phosphate rock, of which there are enormous deposits 
n the United States. 
For many years the importance of the phosphate industry has been 
Towing steadily. At present the conditions in Europe incident to 
yar have temporarily curtailed the output of phosphate rock, in this 
untry as well as abroad, but on the termination of nhoguil hates the 
6819°—Bull. 312—15—1 
