SFERISKA PERLOR MED HOG KOLHALT OCH FORFARANDE FOR DERAS FRAMSTELLNING

摘要

1457013 Cellular carbon beads BATTELLE MEMORIAL INSTITUTE 19 March 1974 [20 March 1973] 12199/74 Heading C1A [Also in Division C3] The invention comprises cellular spherical beads of high carbon content, containing a plurality of closed cells, wherein the walls of the peripheral cells form a continuous skin marking the limits of the external surface. The skin thickness is preferably 50-500 microns. In one form of bead there is a central part of cells with approximately constant dimensions, surrounded by a peripheral part in which the dimensions of the cells and the volume fraction which they occupy progressively decrease from the inside to the outside. The beads are produced by mixing at least one expansion agent with at least one organic precursor material which on carbonising is transformed into a rigid macromolecular material of the original shape; dividing the mixture into particles; separating the particles one from another and keeping them out of contact with any continuous solid surface; expanding the particles to cellular form and hardening them while still separated one from another and out of contact with any continuous solid surface (thus far the process is that of Specification 1457014; see Division C3) ; and carbonising, e.g. by heating to 1000‹-1200‹C for 1-24 hr in a non-oxidizing atmosphere such as argon or nitrogen.