<p>Mixing apparatus having an elongated cylindrical mixing chamber with an inlet end and an outlet end and an elongated closed jacket surrounding and spaced from the mixing chamber. The jacket is divided into a number of annular chamber each of which is in communication with the mixing chamber through a ring of inlet passages extending through the wail of the mixing chamber. Each inlet passage in each ring of inlet passages is at an angle toward the outlet end of the mixing chamber and is angularly skewed relative to the axis of the mixing chamber. A throat nozzle is located at the inlet end of the mixing chamber to supply material to the mixing chamber.</p>