Research of Suitable Material Layer Thickness for Lamination Comminution Based on Numerical Simulation of Real Failure Process Analysis
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摘要:
高压辊磨机以其独特的层压粉碎原理优势在金属矿山节能降耗中发挥着重要的作用，由于矿石力学性质、均质性、给矿粒度的不同，在相同设备中不同的床层厚度，会影响其层压粉碎效果。本文以鞍山式赤铁矿石为研究对象，基于矿石宏观力学性质及真实破裂数值模拟（RFPA），表征层压粉碎适宜颗粒床层厚度。首先进行矿石的抗压强度、抗拉强度试验，借助数值模拟表征矿石的均质度m。构建直径为10 mm赤铁矿颗粒、不同床层厚度的数值模型，在水平方向有约束条件下进行压载试验，模拟高压辊磨机的层压粉碎过程，通过应力传递、三维裂纹贯通破坏模式、相对粉碎能耗，确定适宜的料层厚度。结果表明，层压粉碎床层厚度为8层颗粒直径的粉碎形式表现为对角线贯通，有利于应力传递，促进整个床层颗粒产生粉碎，能量利用率高。本文的研究结果，为工业上确定高压辊磨机适宜的料层厚度提供研究基础。
Abstract:HPGR (High pressure grinding rolls) plays an important role in energy-saving and consumption-reduction in metal mines owing to its unique advantages in the lamination crushing principle. Given the differences in mechanical properties, homogeneity and particle size of feed ores, different material layer thickness in a same equipment affects HPGR lamination crushing performance. In this study, taking Anshan-type hematite ores as the research object, suitable particle layer thickness for lamination crushing was characterized based on the macro-mechanical properties and the numerical simulation of real fracture (RFPA) of ores. The tests of compressive strength and tensile strength of standard ore samples were first carried out, and the homogeneity m of ore was characterized by numerical simulation. Then, numerical models of variable layer thicknesses with Φ10 mm spherical hematite particles were configured, and the ballast tests were performed with horizontal constraint simulating the HPGR lamination comminuting process. Finally, an appropriate layer thickness was determined by analyzing the processes of stress transfer and three-dimensional crack penetration failure coupled with the relative energy consumption. It was shown that the fracture mode of configuration with a thickness of 8 layers was diagonal penetration, which was conducive to stress transfer promoting the comminution of particles in the whole bed with a high energy efficiency. Results provided a research basis for determining a suitable layer thickness of HPGR in industry.
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表 1 岩石单轴抗压强度试验结果
Table 1. Test results of rock uniaxial compressive strength
编号 直径/mm 高度/mm 横截面积/mm2 最大破坏载荷/kN 单轴抗压强度/MPa 轴向弹性模量/MPa 泊松比 1 49.72 100.20 1940.58 423.77 218.37 189037 0.3613 2 49.50 99.50 1923.45 470.25 244.48 156205 0.3584 3 49.52 100.10 1925.00 519.69 269.97 149780 0.3554 4 49.70 100.28 1939.02 560.64 289.13 163042 0.3291 5 50.06 100.10 1967.21 525.56 267.16 169326 0.3458 平均值 499.98 257.82 165477 0.3500 
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表 2 岩石单轴抗拉强度试验结果
Table 2. Test results of rock uniaxial tensile strength
试样
编号直径/mm 长度/mm 质量/g 密度/(kg·m−3) 破坏最大
载荷/kN岩石抗拉
强度/MPa1 50.08 25.26 169.87 3415.8 35.39 17.82 2 50.04 25.10 172.63 3498.8 33.54 17.01 3 49.60 25.06 169.74 3507.7 32.80 16.81 4 50.10 25.20 169.82 3420.3 30.70 15.49 5 49.70 25.24 169.30 3459.3 37.50 19.04 平均值 3460.4 33.40 17.23
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表 3 岩石数值模型试验结果
Table 3. Test results of Rock numerical model
m 抗压
强度σ/MPa弹性
模量 E/GPa细观抗压
强度σ0/MPa弹性
模量E0/GPa数值模拟
结果/MPa2.6 257.82 165.48 948.22 211.48 253.19 2.8 257.82 165.48 885.37 208.67 250.63 3.0 257.82 165.48 834.37 206.85 255 3.2 257.82 165.48 790.86 203.84 252 3.4 257.82 165.48 754.52 201.8 252.2
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