| 摘要 |
PURPOSE:To obtain the titled molded article with a low residual sulfur content useful for gaskets, etc., by dipping graphite particles in a mixed solution of concentrated sulfuric acid and a strong oxidizing agent, washing the resultant intercalation compound with water and aqueous solution of sodium hydroxide and then water, and expanding and molding the washed compound. CONSTITUTION:Graphite particles, preferably natural scaly graphite from the viewpoint of ready availability is dipped in a mixed solution of concentrated sulfuric acid and strong oxidizing agent to form an intercalation compound. Various oxidizing agents including nitric acid may be used as the above-mentioned oxidizing agent, but a system of sulfuric acid and nitric acid is cited as a preferred example. 10pts.wt. graphite particles is treated with a mixed acid of 20- 50pts. wt. concentrated sulfuric acid and 5-20pts.wt. concentrated nitric acid, and then the treated graphite is separated in a suitable deacidifying apparatus. The separated graphite is then washed with 50-200pts.wt. 1-5wt% aqueous solution of sodium hydroxide and then with 100-200pts.wt. water and dehydrated to give a graphite intercalcation compound, which is subjected to the well- known expanding and molding steps to afford the desired expanded molded graphite article. |
