| 摘要 |
PURPOSE:To enable the removal of sulfur from expanded graphite, easily and effectively, by oxidizing the expanded graphite containing residual sulfur with air in a specific air atmosphere. CONSTITUTION:An expanded graphite containing residual sulfur is exposed to the atmosphere composed of air flowing at a rate of 0.1-10 liter/min 1g of the expanded graphite, at 400-650 deg.C for 0.2-15hr, to effect the oxidization of the expanded graphite with air. Usually, an expanded graphite contains about 800- 6,000ppm of residual sulfur, however, the sulfur content can be reduced to about 0-300ppm by the above process. The problem of the apparatus corrosion can be solved nearly completely at a maximum sulfur content of about 300ppm. When the expanded graphite is used in the application such as solid catalyst for which the presence of impurities is absolutely prohibited, it is necessary to keep the residual sulfur to 0ppm, and it can be achieved by carrying out the above air- oxidation process under controlled condition. |
