Assessing vibrating viscometers in slurries

Bibliography: pages 49-50.A number of vibrating transducers for viscosity measurement described in the literature have been evaluated, with a view to developing an instrument for measuring gold-mine slurries. Appropriate electronic measuring methods are discussed, and related theory using a simple mathematical model is derived, and verified experimentally. A low frequency vibrating transducer is described which is capable of measuring apparent viscosities of slurries. Measurements made on Newtonian liquids at four different frequencies using the same transducer agree to ± 2%, and correlate closely with measurements made using a Redwood orifice viscometer. In order to determine the accuracy of the transducer for slurries, comparative measurements at four frequencies are used to obviate the need for a reference instrument. For a dilute (Newtonian) slurry, these measurements agree to ± 10%, but similar measurements on more concentrated (non-Newtonian) slurries show marked divergence of the curves at high frequencies. It is suspected that this behaviour is a property of the slurries, related in some way to their observed non-Newtonian behaviour. These results are of a qualitative nature, but point to the possible usefulness of the instrument for slurry measurement