Patent Number: 046684441
Section: description

The following example explains the process of the invention in more detail. The process can comprise, consist essentially of or consist of the stated steps with the recited materials. Unless otherwise indicated all parts and percentages are by weight. DETAILED DESCRIPTION EXAMPLE Isotropic graphitized soft coal secondary pitch coke powder was treated with phenol formaldehyde in the ratio of 4:1 to 6:1, there was added to the resin between 3 and 10 weight percent of hexamethylenetetramine as hardening agent. Half shells having a green density of about 1.2 g/cm.sup.3 were preliminary pressed from the thus produced molding powder at elevated temperature (about 100.degree. C.). A further portion of the molding powder was mixed with coated particles and preliminarily pressed to spherical nuclei having a green density of likewise about 1.2 g/cm.sup.3 (based on the molding powder components). The preliminarily pressed portions were preheated to about 80.degree. C., assembled in the final mold matrix and final molded, whereby to harden the binder the temperature of the charge was increased up to 170.degree. C. After the final molding the elements were carbonized in known manner and finally calcined in a vacuum at temperatures up to 2000.degree. C. The elements thus produced on the average exhibited higher crush strengths than the conventionally produced elements. In the case of using floating matrices the anistropy of the elements defined as the quotient of the linear thermal coefficient of expansion parallel and perpendicular to the molding direction is about 1.2 and accordingly within the band width of the elements conventionally produced by quasiisostatic molds. It is not necessary to encase the coated particles during the molding process to avoid particle damage with these elements.