High-efficient thickening techniques for solid-liquid separation circuits

The principles and techniques of high-efficient flocculation with adding polyacrylamide solution as the flocculation agent for some uranium leach slurry in high-efficient thickeners were discussed. The investigation showed that the most important factors in thickening techniques were dilution of the polyacrylamide flocculant, appropriate dilution of leach slurry and optimum agitation for mixing to disperse the flocculant throughout the slurry without degrading floccules. For the developed high-efficient thickeners much considerations were took to the clarity of the overflow by way of the special design of the central feeding well in the thickener so as to form a stable thick percolating layer during solid-liquid separation. The φ 1200 mm and φ 2300 mm high-efficient thickeners with accompanying two-cylinder diaphragm pumps as well as automatic controlling system were successfully developed and have been put into commercial test in a uranium mine. As a result, the processing capability per unit area of each high-efficient thickener was 8-11 times higher than that of the conventional one. The technical performances were greatly improved with solid content mostly far less than 175 ppm in the overflow, 45-52% solid in the under flow with consumption of polyacrylamide 34-130 g/t