Changes in the ultrafine structure of anthracites upon heat treatment

✍ Scribed by S.P Nandi; V Ramadass; P.L Walker Jr.

• Publisher: Elsevier Science
• Year: 1964
• Tongue: English
• Weight: 873 KB
• Volume: 2
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(64)90034-x

✦ Synopsis

Changes in the ultrafine structure of three 200 x 325 mesh Pennsylvania anthracites, of VM ranging from 4.5 to 9.0 per cent, upon heat treatment in an oxygen-free atmosphere have been followed. After going through slight maxima at lower HTT, the total surface areas decreased sharply upon heat treatment at 900°C. Helium and mercury densities increased monotonically with increasing HTT. Unsteady-state diffusion of gases from the anthracites has been measured. The diffusion rate decreased sharply and continuously upon heat treatment at temperatures between 600 and 17OO"C, primarily because of a steady increase in activation energy for diffusion. The increase in activation energy is attributed to a continuous decrease in the size of the ultrafine pores with increasing HTT.