BIWETTED ULTRAFINE SOLIDS AND STRUCTURE FORMATION IN OIL SANDS FINE TAILINGS

A high water holding capacity of oil sands fine tailing has been attri buted to the presence of ultrafine ( < 0.2 mu m) clay fractions. On th e basis of hydrophobic character two major types of ultrafines are rec ognized: associated with a significant coverage or organic matter and preferentially hydrophilic solids. The effect of biwetted solids on th e colloidal stability of ultrafine clays in aqueous suspensions has be en studied by dynamic light scattering and H-2 n.m.r. methods. The org anic matter associates with the surfaces of the biwetted solids is bel ieved to be responsible for their accelerating effect on aggregation. The results indicate that prevention, or reduction, of the amount of b iwetted solids entering the tailings pond could be beneficial.