We study the elastic scattering of quantum particles based on a real Hilbert space approach to quaternionic quantum mechanics (
QM) and derive expression for the wave function, the phase shifts, as well as the optical theorem for the case of a hard sphere scattering potential. The strong agreement between these new quaternionic results and the corresponding results in complex quantum mechanics reinforce the validity of the
QM generalization of ordinary complex quantum mechanics (
QM).