A process for increasing the bulk density of an aerated powder is provided. The powder is placed in a container. The container is then closed and the gas pressure within the container is increased to a level above atmospheric pressure and at a rate sufficient to cause the powder to compact before a substantial portion of said pressurization gas diffuses into said powder. In one embodiment, the process is utilized to increase the bulk density of an aerated, free-flowing titanium dioxide pigment. Apparatus for carrying out the process is also provided.