Abstract:

From June 2017 to April 2018，frequent pipe plugging accidents occurred in the underground filling of Linglong gold mine，which required a lot of manpower and material resources to restore the pipeline，greatly reducing the filling efficiency.The pipe plugging accident has seriously affected the normal production of the mine and has become one of the factors restricting the development of mine filling technology.In the filling process，the mixing station for filling slurry is generally set on the ground.After the water，full tailings and material C are fully mixed in the mixing barrel，they are transported to the underground goaf through the filling pipeline.The temperature difference between winter and summer in northern China is 30 ℃ to 40 ℃.The hydration reaction of cement is greatly affected by the temperature when the slurry is stirred.When the filling slurry enters the underground through the pipeline，it will be affected by the ground temperature，resulting in the change of slurry temperature.Therefore，the rheological characteristics of the filling slurry in the pipeline are always changing.The rate of cement hydration is greatly affected by the temperature，so the fluidity of the filling slurry will change in different transportation time.Therefore，it is necessary to study the influence of temperature change on the flow performance of the filling slurry.However，there is relatively few research on the influence of temperature change on the hydration of cement.In this paper，the flow characteristics of the filling slurry with full tailings at 20 ℃，15 ℃，10 ℃ and 5 ℃ were studied.According to the actual situation of the mine and the past research in the laboratory，the design slurry concentration is 65% and 68% respectively，and the ash sand ratio is 1∶8 and 1∶12 respectively.The time when material C，tailing and water are mixed together is taken as the starting point of timing.The Origin software was used to process 13 440 experimental data，at each temperature，then we get the shear rate-shear stress curves of different slurry ratio，slurry viscosity coefficient，line graph of relationship between slurry yield stress and slurry temperature and slurry temperature relationship line chart.Through the analysis，the following conclusions are obtained：In the same reaction time，the viscosity coefficient decreases with the increase of temperature；In the same reaction time，the yield stress decreases first and then increases with the increase of temperature；When the yield stress is the lowest，the corresponding reaction temperature of slurry is 10 ℃；The best temperature for the preparation and transportation of the slurry is 10 ℃，at this time，the material resistance loss coefficient of slurry is the smallest.According to the results of this study，when the mine uses high-concentration full tailings filling slurry，the filling temperature can be adjusted appropriately to make the filling slurry reach the optimal state of rheological properties，thereby reducing the occurrence of pipe blockage accidents with the filling slurry.

Key words: filling slurry, rheological properties, temperature, viscosity coefficient, yield stress, advanced rheometer