Abstract: Dense ceramic material in the form of a block is made in a hot uniaxial press, particulate precursor material for the ceramic being supplied in cylindrical metal capsules having a convoluted or bellows-like side wall which are supplied in a stream with an elongated cylindrical spacer of greater diameter between adjacent metal capsules. Each spacer has a recessed end face for accommodating a corresponding end portion of a metal capsule so that the metal capsule is centered and there is restraint against radially outward expansion of the capsule under the heat and pressure which is applied. The apparatus is operated essentially continuously and the stream moves progressively upwardly so that the discharge of processed containers and spacers occurs at the upper end and capsules to be processed and spacers are inserted intermittently at the lower end.