Rheological properties and resistance evolution of cemented unclassified tailings-waste rock paste backfill
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摘要: 為了研究全尾砂?廢石膏體的管道輸送特性,采用流變儀測試了不同尾砂?廢石質量比(尾廢比)及固體質量分數條件下膏體的流變特性,構建了綜合考慮密實度、灰砂比及體積分數的輸送阻力方程。將該方程代入Comsol軟件中進行模擬計算并與環管實測結果進行對比驗證,數值模型所測誤差均在7%以內,說明該模型用于計算全尾砂?廢石膏體的阻力特性是合理的,還模擬了不同濃度、尾廢比及初始速度條件下管道輸送阻力的變化特征。實驗結果表明:塑性黏度和屈服應力隨著粗骨料膏體固體質量分數和尾廢比的增加而增大;由于顆粒間的摩擦效應導致阻力損失隨尾廢比的增加呈先增大后減小的趨勢,阻力損失在尾廢比5∶5處取得最小值;固體質量分數增大導致水含量的降低,使粗骨料漿體難以流動,從而導致阻力損失快速增長;初始流速增加,顆粒運動變得不穩定,摩擦加劇,并于“拐點”—2.2 m·s?1處阻力損失的增長率大大提高。研究成果對于粗骨料膏體管輸系統的設計具有一定借鑒意義。Abstract: Coarse aggregate paste filling is the core direction of today’s mine development. The coarse aggregate filling can effectively reduce the discharge of the solid mine waste, which is conducive to the realization of safe, clean, and efficient mining of the deposit and can also reduce the production costs of infill mining and promote the coordinated development of green mining. To study the pipeline conveying characteristics of the tailing?waste rock paste, the rheological properties were tested by a rheometer under different tailing?waste rock ratios and solid content conditions. A resistance equation integrating the compactness, water?cement ratio, and volume concentration was constructed. This was then brought into the Comsol software for simulations and compared with the actual measurement results of the ring pipe. Errors measured by the numerical model are verified to be all within 7%, indicating that the model reasonably calculated the resistance characteristics of the tailing-waste rock paste. Variation characteristics of the pipeline conveying resistance under different solid contents, tailing?waste rock ratios, and initial velocity conditions were also simulated. Experimental results show that the plastic viscosity and yield stress increase with the solid content and tailing?waste rock ratio. Due to the friction effect between the particles, the resistance loss tends to increase and then decrease with the tailing?waste rock ratio. The increase in the solid content leads to a decrease in the water content of the paste, which consequently results in difficulty in the flow of coarse aggregate slurry and a rapid increase in the resistance loss. The initial flow rate increases, the particle motion becomes unstable, the friction increases, and the growth rate of the drag loss increases greatly after the “inflection point” of 2.2 m·s?1. It is recommended that the mine should be filled with a tailing?waste rock ratio of 5∶5 and an initial flow rate of 2.2 m·s?1. The results have certain reference significance for the design of a coarse aggregate paste pipeline conveying system, which helps the development of coarse aggregate paste conveying technology and also has a positive effect on reducing the pipeline conveying resistance and extending the conveying distance.
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表 1 充填材料化學成分
Table 1. Chemical composition of the filling material
Materials SiO2 CaO MgO Al2O3 Fe2O3 SO3 K2O TiO2 MnO Other Unclassified tailing 42.20 3.73 32.71 4.04 12.14 3.37 0.39 0.33 0 0.85 Waste rock 47.71 16.39 15.22 7.81 7.17 2.58 1.95 0.54 0.12 0.39 表 2 充填材料活性指標
Table 2. Activity index of the filling material
Materials Alkalinity rate Activity rate Mass index Activity Unclassified tailing 0.79 0.1 0.24 Low activity Waste rock 0.57 0.163 0.54 Low activity 表 3 混合骨料的堆積密實度
Table 3. Stacking compactness of the mixed aggregate
Tailing?waste rock ratio Density of mixed aggregate/(g·cm?3) Compactness,Φ 0∶1 2.826 0.476 1∶9 2.815 0.489 2∶8 2.801 0.508 3∶7 2.788 0.521 4∶6 2.774 0.542 5∶5 2.761 0.593 6∶4 2.752 0.614 7∶3 2.743 0.529 8∶2 2.732 0.501 9∶1 2.724 0.496 1∶0 2.715 0.464 表 4 流變測試方案
Table 4. Rheological test summary
Scheme Solid mass fraction/% Volume fraction/% Cement?sand mass ratio Water?cement mass ratio Tailing?waste rock ratio Bulk density 1–3 67 55.20% 1∶4 1.41 4∶6/5∶5/6∶4 0.542/0.593/0.614 4–6 69 52.39% 1∶4 1.57 4∶6/5∶5/6∶4 0.542/0.593/0.614 7–9 71 49.72% 1∶4 1.75 4∶6/5∶5/6∶4 0.542/0.593/0.614 10–12 73 47.19% 1∶4 1.94 4∶6/5∶5/6∶4 0.542/0.593/0.614 13–15 75 44.77% 1∶4 2.14 4∶6/5∶5/6∶4 0.542/0.593/0.614 16–18 77 42.47% 1∶4 2.35 4∶6/5∶5/6∶4 0.542/0.593/0.614 表 5 流變參數擬合結果
Table 5. Fitting results of rheological parameters
Tailing?waste
rock ratioSolid mass fraction /% Yield stress/Pa Plastic viscosity/(Pa·s?1) R2 4∶6 77% 184.3155 0.7424 0.9971 75% 85.8522 0.6476 0.9977 73% 61.3761 0.4344 0.9924 71% 43.5327 0.2677 0.9889 69% 26.9710 0.1815 0.9844 67% 18.0002 0.1422 0.9631 5∶5 77% 206.5693 0.8278 0.9743 75% 138.0741 0.7509 0.9993 73% 91.1335 0.6465 0.9992 71% 69.4989 0.4144 0.9927 69% 53.8325 0.2737 0.9876 67% 39.4085 0.1673 0.9798 6∶4 77% 236.9843 0.9017 0.9612 75% 172.7104 0.8651 0.9849 73% 118.8447 0.7526 0.9996 71% 81.1709 0.5074 0.9986 69% 63.0234 0.3453 0.9941 67% 46.6048 0.2311 0.9861 表 6 屈服應力擬合結果
Table 6. Yield stress fitting result
Tailing?waste rock
mass ratioFitting equation of the yield stress and
slurry volume fractionR2 Fitting equation of the yield stress and slurry
water?cement ratioR2 4∶6 ${\tau _0} = 0.0029{{\text{e}}^{20.49{C_{\text{v}}}}}$ 0.97 ${\tau _0} = 1384.01{(w/c)^{ - 5.10}}$ 0.97 5∶5 ${\tau _0} = 0.113{{\text{e}}^{13.91{C_{\text{v}}}}}$ 0.99 ${\tau _0} = 820.24{(w/c)^{ - 3.46}}$ 0.99 6∶4 ${\tau _0} = 0.196{{\text{e}}^{13.18{C_{\text{v}}}}}$ 0.99 ${\tau _0} = 894.21{(w/c)^{ - 3.28}}$ 0.99 表 7 參數擬合結果
Table 7. Parameter fitting result
Tailing-waste
rock ratioYield stress R2 Plastic viscosity R2 a b a1 b1 k 4∶6 1232.80 ?4.85 0.97 1.98 0.64 5.58 0.97 5∶5 799.77 ?3.21 0.99 3.84 2.39 2.72 0.99 6∶4 924.96 ?3.03 0.99 1.28 0.77 3.76 0.99 www.77susu.com -
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