Determination of characteristic properties of mineral suspension for calculating the particle velocity

Abstract

Calculations of hydraulic devices for separating mineral suspensions and extracting valuable components and waste are based on determining the speed of constrained deposition and surfacing of particles. When determining the speed, it is necessary to know such characteristics of the suspension as viscosity, porosity, density. The article offers a method for analytical calculation of these indicators. Its peculiarity is that the definition of these characteristics is associated with only one parameter – the volume density of the medium (substance). It is easily determined in practice by weighing a sample of suspension in a container of a known volume. This method is illustrated by the characteristics of two water-based mineral suspensions: with a solid particle density of 2.55 g / cm3 (ash and slag waste from a thermal power plant) and a density of 2.0 g/cm3 (crushed tuff). For these suspensions, the approximate dependences of these characteristics on the density of the medium (substance) are established. It is established that the application of the most common suspension model in the form of a discrete cellular structure provides acceptable limitations of the studied characteristics. The obtained values are within the scope of typical indicators of mineral pulps in the working zone of hydro-classifiers and hydro-separators. However, a number of well-known formulas for the speed of restricted movement that use this model are unacceptable for calculating hydraulic devices since they take into account inflated values of characteristics. The described method can be used for dispersed systems of two or more phases, for example, using weighted average values of components. The proposed method for calculating the characteristics of suspensions is suitable for practical use, given that the hydraulic apparatus receives already classified raw materials and the particles have a small variation in shape and size. The obtained analytical dependences of suspension characteristics on density are used for calculating speed of both constrained and free movement of particles, which is the basis for determining technological and design parameters in the design of hydraulic devices and apparatuses.