| Tailings filling can not only save the storage cost and reduce environmental pollution, but also can effectively avoid geologic subsidence, etc. "Guiding opinions on further strengthening the supervision and administration of the tailings guidance" unveiled in 2012 expressly provide that the newly-built mines must argue whether the filling mining method is adopted, and the filling mining method should be given prior consideration. Under this background, the filling mining method in the ratio of mining applications gradually increases. In the filling system, the tailings pipeline system is one of the main links. In order to let pulp be conveyed to the filling station safely and economically. Taking the phosphate tailings of in a certain mine in Guizhou as test object, the optimization experiment on Friction Reducing Additive of phosphorus tailings pipeline transportation was carried out.(1)To investigate the effect of phosphate tailings properties on pipeline transportation,study on the rheological properties and composition characteristics and main rheological features and sedimentation characteristics of the phosphorus tailings were conducted, the results are as follows:Based on sieve analysis of phosphate tailings, the content of-75?m is 67.76%, the nonuniform coefficient is 2.96. The grain size is fine, the coarse fraction content is less and gradation is adverse, which isn't conducive to pipeline transportation directly.(2) At the same shear rate, the viscosity and pulp density of phosphate tailings were positively correlated, that is, the greater the concentration, the higher the viscosity. For pulp concentration is 75%, when the shear rate is 25 r/min, the viscosity is 2322.1 m Pa.s, it is not conducive to pipeline transportation with high concentrations of tailings.(3)The overall rate of natural sedimentation for Phosphate tailings pulp, and with the increase of pulp density and the decease of settling velocity, it is not easy to fill in the pipeline.Based on the analysis results of XRD, XRF, combined with the drag reduction agent chemical mechanism of drag reduction,selection of PEO,PAM, CTAB, 1831 and LAB as test reagents.To study the drag reduction effect and dosage of reagents,a drag reduction aqueous solution drag reduction test were conducted.The results show that the drag reduction effect of CTAB is the best which can up to 55.65%,then followed by PAM, the PEO, 1831, LAB.The five kinds of drag reduction agent have certain drag reduction effect,and can be considered as a subsequent phosphate tailings pipeline drag reduction agent.And five kinds of medicament optimum dosage concentrated in 300 ppm and 500 ppm.Experimental study on the drag reduction effect, the shear performance and corrosion resistance of PEO, PAM, CTAB, 1831 were conducted. the results show that the drag reduction effect of CTAB is the best which can up to 59.69%; CTAB, 1831, lauroylamidopropyl betaine has good shear resistance, while the drag reduction of PEO, PAM is irreversible; the corrosion of 1831 is the largest during test time, CTAB takes second place, the remaining drug have no obvious corrosion phenomenon.Through optimization experiment on drag reduction, CTAB is finally selected as drag reducing additive for phosphorus tailings pipeline transportation. In order to further study the drag-reduction characteristics of CTAB in phosphate tailings pipeline transportation with high concentrations, experiment on the drag reduction characteristics of the different reagent dosage under the condition of different ratio of phosphate tailings pulp with the concentration of 60% was conducted, results show that when the dosage of CTAB is 400 PPM, the molecular ratio of CTAB/Na Sal is 1, the drag reduction rate is maximum, which can up to 56.86%. |
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