A carbonaceous material of a grain size below 100 Mu is mixed with a reversibly softening binding agent at a temperature above the softening point of the binding agent and in the presence of water or water vapor. There results a doughy mass which is comminuted to the desired grain size. The comminuted material is then subjected to a preliminary low temperature carbonization followed by carbonizing or coking the material and then activating it. The process permits obtaining of small size substantially ballshaped adsorption coke in a highly economical manner.