This chemical equation represents a series of reactions involving various calcium compounds:

Ca(NO3)2 (calcium nitrate) is first decomposed into CaO (calcium oxide) and N2O5 (nitrogen pentoxide):
2Ca(NO3)2 → 2CaO + 4NO2 + O2

CaO then reacts with Ca(OH)2 (calcium hydroxide) to form Ca(OH)2 (calcium hydroxide):
CaO + Ca(OH)2 → 2CaO + H2O

Finally, CaO reacts with CaSO4 (calcium sulfate) to form calcium silicate and calcium sulfate:
CaO + CaSO4 → CaSiO3 + CaSO4

Overall, the series of reactions can be summarized as:
2Ca(NO3)2 + Ca(OH)2 + CaSO4 → 2CaSiO3 + 3CaSO4 + 4NO2 + O2 + H2O