Phosphorus Tailings-based Backfill Material Rheology And Transport Drag Reducer Mechanism

Phosphorus tailings is a solid waste produced in the process of phosphate ore dressing.The utilization rate of phosphorus tailings in China is low,and its storage will not only occupy a lot of land,but also have adverse effects on the surrounding environment.Raw material of phosphorus tailings filling are analyzed in this paper,the physical and chemical properties of fly ash,cement and rheology of the filling pulp,by rheological test,the sedimentation test,compressive strength test and numerical simulation of the additives on the properties of slurry flow,the influence law of compressive strength,optimize phosphate tailings filling material(PTFM)configuration parameters,The action mechanism of drag reducer was analyzed.The research results have guiding significance for improving the rheological properties of PTFM and improving its transportation efficiency.The results obtained are as follows:1.Bingham model was suitable for fitting the rheological curves of PTFM slurry prepared,and the fitting correlation coefficients were all greater than 0.961.PTFM slurry concentration has a great effect on its rheological properties,and the yield stress increases with the increase of slurry concentration.Adding CTAB can significantly change the rheological parameters of slurry.When the dosage of CTAB increases from 0 g/t to 600 g/t,the yield stress of slurry decreases from 30.61 Pa to10.97 Pa,and the plastic viscosity decreases from 0.44 Pa·s to 0.23 Pa·s.When the average particle size of phosphorus tailings decreases from 82.30 ?m to 46.58 ?m,the yield stress of slurry decreases from 16.96 Pa to 8.42 Pa.When the average particle size continues to decrease to 44.55 ?m,the yield stress of slurry increases to 12.96 Pa.With the decrease of the average particle size of phosphorus tailings,the plastic viscosity of slurry decreases first and then increases,but the change trend is not as significant as the yield stress2.The research results of the influence of drag reducer on PTFM transport characteristics show that:When the concentration of PTFM is 74%,the addition of drag reducing agent CTAB can increase the transport flow of phosphorus tailings slurry.When the addition amount of CTAB increases from 0 g/t to 600 g/t,the transport flow of phosphorus tailings slurry increases by 3.43 L/min.At the same time,the addition of CTAB can significantly reduce the viscosity of PTFM and phosphorus tailings slurry.3.The drag reduction mechanism analysis of PTFM slurry by CTAB shows that after adding CTAB,the surface of particles in the slurry has the same positive charge,and the electrostatic repulsion between particles increases and dispersions,thus reducing the viscosity of PTFM and phosphorus tailings.The compressive strength test results show that the compressive strength can be improved by controlling the addition amount of CTAB.Considering the conveying flow rate and compressive strength of PTFM slurry,the appropriate addition amount of CTAB is 600 g/t.4.The finite element software Ansys-fluent was used to simulate the conveying characteristics of PTFM slurry in the pipeline.The results show that the local resistance generated by PTFM flow in the pipeline can be concluded that the greater the concentration,the greater the local resistance,and the appropriate backfill concentration is 74%.As the initial flow rate of PTFM slurry increases,the local resistance gradually increases,and the appropriate initial flow rate is 1.8m /s.