It is stated in this document (https://www.thevespiary.org/rhodium/Rhodium/chemistry/tcboe/chapter3.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/tcboe/chapter3.html)
), about midway down the page under the heading "White Phosphorus", that the following reaction occurs when Calcium Phosphate and Silicon Dioxide are heated together at high temperatures:
2 Ca3(PO4)2 + 6 SiO2 --> 6 CaSiO3 + P4O10
It also says that when mixed with powder carbon and heated to 1450C, the phosphorus pentoxide reacts further to produce white phosphorus and carbon monoxide.
The question is simply this: At what temperature does the first step of the reaction occur? Or is the initial reaction the one which requires such high temps in the first place?
Thanks, SWID.
PostScript: SWID is aware that P2O5 is commercially available for reasonable prices. He just wants to make his own for fun. :P