| ABSTRACT:The mining conditions of ore body were complex with low grade in SuSong phosphate. Karst and fissure water were abundant and the rock mass was unstable. Besides, the storage capacity of tailings pond was limited and tailings discharge caused serious pollution to the surrounding environment. A reliable filling system was established to guarantee the need of filling, reduce the loss rate and dilution rate, improve the safety of mining, reduce the emissions of tailings, extend the service life of tailings pond, protect the surface environment. In this paper, according to the actual situation of SuSong phosphate, the research of key technologies with the high concentrations graded tailings backfill technology were conducted. A in-depth research concerning ratio parameters of graded tailings filling, the filling method and capacity, the filling station site, the slurry preparation and delivery system, the dehydration and sedimentation effects of horizontal silo and the reliability of pipeline transportation system with gravity is carried out on the basis of site investigation and laboratory testing, with the theory of fluid mechanics mathematical method and fluid simulation software as the main means. The main research content and conclusions are as follows:(1) The chemical and physical properties of full tailings and graded tailings are analyzed. By selecting the graded tailings as the filling aggregate,32.5ordinary portland cement as cementing material, contrast ratio is1:4, slurry concentration72%through the laboratory ratio testing.the results of flow performance testing show that the slurry of recommended ratio has a good performance with transportation, which is able to meet the requirements of pipeline.(2) By performing the balance calculation of mining and filling, the capacity of filling system of SuSong phosphate is80m3/h. Through calculation and analysis, the pipe gravity method is used and the horizontal sand positions is used to storage aggregate.(3) By site investigation and analyzing technical and economic indicators, AHP&EM-TOPSIS comprehensive evaluation system is established, the south air shaft is the best plan of station site. (4) By calculation, the slurry preparation system and pipeline transportation systems are studied to determine the size of horizontal horizontal silo, stable silo and cement silo and other major facilities to select the programs of sand feeding system, drainage system, slurry transport system and other systems.(5) On the basis of the interior settlement test, the sedimentation rate and the final concentration of graded tailings are tested to determine the dehydration structure of horizontal silo. And the horizontal silo is modeled with the Fluent software to simulate the enrichment process of tailings in the silo. The results show that the concentration of concentrated graded tailings in the silo is able to reach85%, which are in line with the results of laboratory tests to meet system requirements.(6) The comparison results of the critical velocity and work velocity of filling slurry show that the pipeline system is reliable. The simulation of slurry transport process is completed. The results show that the flow state of slurry is smooth, and the pressure loss is less than the gravitational potential energy to meet the gravity flow. |
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