LABORATORY SEPARATION OF CLAYS BY HYDROCYCLONING

over the more commonly used sedimentation/decantation method for clay separation. Large amounts of relatively concentrated clay suspensions may be separated in a matter of minutes. In addition, no dispersing agents are required and the shear conditions encountered by the suspension during passage through the hydrocyclone l ad to particle disaggregation both in the silt and sub-micron size range. Formulae relating design factors of the hydrocyclone to separation performance xist but are of limited value as they are unable to predict the maximum particle size of the clay product or percentage r covery of any particular size of particle. Such data, determined from practical trials, are given for kaolinite, smectite and mixed-assemblage clay suspensions. Design limitations prevent the effective separation of clay products with 'cut-off ' sizes finer than 5 #m. The hydrocyclone, as a vehicle for solid-l iquid separations, has a range of uses which vary from de-watering and de-sliming to particle-size fractionation. Its fast throughput of slurry and capacity for dealing with suspensions of high solids content are exploited in various mineral dressing operations where removal of clay and other fines is a necessary prelimi-nary to treatment of cleaned or washed sands. Where the clay itself is the principal produc