9. The purpose of sometimes adding exothermic materials to sand is
A. To heat the core
B. To produce directional solidification by the generation of heat
C. To heat the sand
D. To dry the mould
9. The purpose of sometimes adding exothermic materials to sand is
A. To heat the core
B. To produce directional solidification by the generation of heat
C. To heat the sand
D. To dry the mould