Comparison of ultra-flocculation reactors applied to fine quartz slurries

•Flocculation studies were carried in six different ultra-flocculation reactors at high shear rates.•The six ultra-flocculation reactors allow flocculation in times below of 10 s.•Results showed an average improvement in settling velocity and turbidity below 100 NTU compared with flocculation in cylindrical columns at low shear rate.