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RESEARCH OF THE RHEOLOGICAL PROPERTIES OF PULPS IN THE SEPARATION OF MINERAL RAW MATERIALS

Artem Romashev

Abstract

Separation processes are highly influenced by medium in which separation is performed, particularly its rheological properties. One of the most important rheological parameter of medium is viscosity. Many researchers have noted the primary role of viscosity in separation processes. During classification of milled raw, with an increase in the viscosity of the medium (up to a certain limit), the overall productivity of the hydrocyclone increases and the distribution of liquid volumes leaving through the apex and vortex finder. During flotation process hydrocarbons which have different composition, structure and molecule size intensify hydrophobic properties of mineral with increasing of viscosity. Despite the importance of rheological properties in minerals processing the initialization of it causes difficulties. In particular, it was noted that the apparent viscosity of the slurry is usually measured at a certain shear rate and the final velocity of the ore particle is calculated from this value of viscosity, however this may be incorrect for non-Newtonian liquids for which viscosity is not a simple function and, in terms of process it is important that the viscosity experienced by the particle under the process conditions must be known. In this regard, the initialization and modeling of the mineral suspensions viscosity is an important task that promotes intensification of the separation process. In the paper the approach to modeling of rheological properties in ANSYS Fluent software is proposed. The standard k-? turbulence model for solution was applied. It is semi empirical and suitable for describing the flow of a non-Newtonian fluid. Also, the non-Newtonian Power Law (NNFPL) method was used in the simulation, which is more detailed than the User-Defined Function (UDF) approach, which directly describes the exponential viscosity-temperature relationship.

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