A particulate cellulose derivative is obtained in a process of grinding and drying a moist cellulose derivative wherein A) a cellulose derivative having a moisture content of from 60 to 95 percent, based on the total weight of the moist cellulose derivative, is provided, B) the moist cellulose derivative is dried and partially ground in a gas-swept impact mill and C) the ground and partially dried cellulose derivative is contacted with an additional amount of a drying gas outside the gas-swept impact mill. The obtained particulate cellulose derivative has a high untapped bulk density and a good flowability.
