Influence of ultrasonic treatment on the viscosity of aqueous-clay suspensions for sand-clay mixtures

The article considers the influence of the frequency and time of the ultrasonic treatment on the viscosity of the bentonite suspensions. The object of the study is the bentonite clay of Zyryansk deposit; on the basis of it water-clay suspensions were prepared. The suspensions were examined for conditional viscosity, which was determined by the viscometer VZ-2 and for the dynamic viscosity which was determined by using the rotary viscometer Brookfield Rheo V 2.8. In processing the dispersion system is divided into four zones: the zone of active dispersion of the solid phase, the transitional zone, wave and hydrodynamic coagulation zone and sustainable structural and rheological equilibrium state of the solid solution phase. It has been shown that the treatment of clay suspensions by the ultrasonic treatment depending on the time and processing power causes both dispersant and aggregated action. It is established that the water-bentonite clay suspensions are the thixotropic non-Newtonian fluids with pseudoplastic flow. The ultrasonic treatment during 15 minutes leads to the decrease in the relative viscosity of the suspensions by reason of formation of the periodic colloidal structures, after which the process of the autocoagulation begins. The ultrasonic treatment by field of 20 kHz during 1, 5 minutes leads to the decrease in the dynamic viscosity of the suspensions by reason of dispersion of the particles. The ultrasonic treatment by field of 50, 60 kHz during 1, 5 minutes leads to the increase in the dynamic viscosity of the suspensions by reason of coagulation of the particles. It is established that the stability of the activated coagulation system to mechanical stress is considerably smaller than the original bentonite clays that allows to realize for more uniform distribution of the clay minerals over the surface of the quartz sand and provides increasing the number of the cohesive and adhesive contacts and improving the physical and mechanical properties of the mixtures in forming.