Ca3(PO4)2 + 5C + 3SiO2
2P + 5CO + 3CaSiO3
or2Ca3(PO4)2 + 10C + 6SiO2
P4 + 10CO + 6CaSiO3

Calcium phosphate react with carbon (coke) and silicon dioxide to produce phosphorus, carbon dioxide and calcium silicate. The reaction proceeds in electric furnaces at a temperature of 1500°C without air.