Abstract: Disclosed is an apparatus and method for use in particle blasting of particles that change state before the particle blasting, wherein the particles are cast or frozen in mould chambers to give the particles any desired shape. The apparatus for casting or freezing has a rotatable drum in the outer surface of which open mould chambers are formed, which chambers can be closed by the inner surface of a freezing cylinder, the freezing zone of which can be cooled by means of a cooling chamber provided with a cooling medium through supply and discharge tubes. The cast particles are released from the drum, the outer jacket of which may consist of an elastic material of rubber for facilitating the moulding, and then fall down into a discharge chamber, form which they are sucked into the particle-blasting pistol, through a particle discharge tube.