Flocculation process of coal slime water based on flocculation kinetics and its research methods:a critical review

The flocculation-sedimentation of coal slime water is an important unit operation of wet coal preparation process.It is quite valuable to analyze and optimize the flocculation process and improve the flocculation efficiency which results in the improvement of the efficiency of coal preparation.From the perspective of flocculation kinetics, this paper reviews the effect of properties of suspended particles in coal slurry water, chemical system and fluid motion on the collision frequency, collision efficiency and crushing efficiency of flocculation process.The chemical mechanism of flocculation agent to promote flocculation of fine particles and the physical mechanism of turbulent vortex scale regulation to improve flocculation efficiency are summarized.The method of studying flocculation process of coal slime water from flocculation kinetics, computational fluid dynamics(CFD), population balance model(PBM) and discrete element method(DEM), are reviewed.The advantages and disadvantages of the methods are compared when applied to the research on the interaction between coal slime particles, flocculation flow field and coal flocculation.It is considered that the CFD-DEM coupling method is especially suitable for coal slurry water which is multi-component and multi-granular, and is an ideal method for studying the flocculation of coal slime water.