US Patent 7981983 Slurry phase polymerisation process

A process for controlling a slurry phase (co-) polymerisation process in the presence of a polymerisation catalyst, which comprises maintaining the density SPAN of the polymer powder particles (defined as the absolute value of the density difference in g/cm3 between the average density of the polymer particles exiting the reactor with particle size above D90 and the average density of the material with particle size below D10) below 0.005, preferably below 0.003, more preferably below 0.0026, most preferably below 0.0023.