A mathematical description is given of the sintering kinetics for an ensemble of particles on the basis of a unified phenomenological approach, which has been used in a computer model for spherical particle sintering. A series of computer experiments has been performed to check the fit of the model to the physical process. The sintered spherical particle packing has a cluster organization. It is confirmed that the mesostructure is inherited when monodispersed spherical particles are sintered. The computer experiment showed that the phase boundaries initiate macropore nucleation and growth. The sintering rate and the contact area are critical factors determining macropore size and position.