Disclosed is a novel process for manufacturing stable, fluid highly concentrated dispersed aqueous suspensions of calcined clay. The process utilizes the micromixer described in U.S. Pat. No. 3,806,052 to Edward H. Cumpston, Jr. Dry calcined clay is fed to the inlet hopper of the micromixer and mixed with water and one or more conventional clay dispersants before the clay enters the centrifugal zone of the micromixer. A smooth but extremely dilatant paste is discharged from the mill after this first pass. The paste is then recirculated through the micromixer a plurality of times at a higher throughput rate than that used in the first pass.