ON THE ACTIVATION OF ASTURIAN ANTHRACITE FOLLOWING VARIOUS PRETREATMENTS

An Asturian anthracite has been subjected to different pretreatments a nd subsequently activated by steam at 850 degrees C to a total burn-of f of 55 percent. The physical properties (micropore sizes and distribu tions, external surface areas, etc.) of the solids are compared with t hose of the carbon obtained by direct activation. Although the yield i s generally low, it appears that better results are obtained by activa tion following preoxidation in air al 270 degrees C for 3 days. In the case of pretreatments with a mixture of nitrogen, air, and water vapo r at 450 degrees C, the subsequent activation is less efficient. The m icropore volumes and the pore size distributions are similar to those observed for soft precursors, but al a much lower degree of burn-off.