Superphosphate of lime is

Superphosphate of lime: It is a mixture of calcium dihydrogen phosphate and gypsum and is obtained by treating phosphate rock with conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$ 

${\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2+2{\mathrm{H}}_2{\mathrm{SO}}_4+5{\mathrm{H}}_2\mathrm{O}\to \underset{\text{Superphosphate of lime}}{\mathrm{Ca}{\left({\mathrm{H}}_2{\mathrm{PO}}_4\right)}_2.2{\mathrm{H}}_2\mathrm{O}}+2{\mathrm{CaSO}}_4.2{\mathrm{H}}_2\mathrm{O}$