The heart of this novel rotary contactor is the inclusion of a longitudinal partition plate and a series of guide plates. The contactor is kept horizontal, not inclined, and the placement of the guide plates can cause the solids to move in one direction or in the other. With this freedom of movement, one can achieve plug flow or recirculation of solids or any combination of these. Another advantage of this device is that it can hold more solids than the conventional unit, 20-40% versus 10%. The performance equations of this contactor are developed, and its uses in industry today are noted.