On the activation of Asturian anthracite following various pretreatments

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