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首页> 外文期刊>Journal Of The South African Institute Of Mining & Metallurgy >Breakage mechanisms and an encouraging correlation between the Bond parameters and the friability value
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Breakage mechanisms and an encouraging correlation between the Bond parameters and the friability value

机译：断裂机理以及Bond参数与脆性值之间的令人鼓舞的相关性

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It is important to know the breakage mechanism in materials since this knowledge influences the results of subsequent grinding operations. There are two distinct failure mechanisms in breakage: one is tensile micro crack generation at low stresses, which leads to macroscopic failure by disintegration, and the other is formation of shear zones under heavier dynamic impact forces, which generates more fines as seen in crush zones in blasting. Tensile fracturing simply breaks the material into fragments. It is seen as the disintegration of the specimen into two or more separate fragments. This happens under the absence of lateral stresses and the material is free to expand. On the other hand, compressive-shear breakage produces finer fragments due to shear stresses. The first mechanism is observed in laboratory tensile and bending strength tests and the second mechanism is observed both in laboratory brittleness tests and in situ blasting operations under dynamic impact forces. The friability of rocks and ores can be determined by a brittleness test. A test apparatus to determine the friability value has been designed to suit limestone strength characteristics used in cement production. The friability and stored strain energy values of barite, marble, limestone and bauxite have been determined and compared with the corresponding Bond work index (W_i) and grindability index (G) of these materials. The physico-mechanical properties of the tested materials have also been determined to investigate their effect on friability and grinding. The relationships obtained between the indices were in surprisingly good agreement, with high correlations (0.99 and 0.97). The Bond work index and grindability index can therefore be estimated from the friability value, which can be determined more rapidly than the Bond test. But for certain rock types such as andesites the relationships does not hold.
机译：重要的是要知道材料的断裂机理，因为这种知识会影响后续研磨操作的结果。断裂有两种截然不同的破坏机理：一种是在低应力下产生拉伸微裂纹，这会因崩解而导致宏观破坏，另一种是在较大的动态冲击力作用下形成剪切区，这会在压碎区产生更多的细屑。在爆破中。拉伸断裂只是将材料破碎成碎片。这被视为将标本分解为两个或更多个单独的碎片。这是在没有侧向应力的情况下发生的，并且材料可以自由膨胀。另一方面，由于剪切应力，压缩剪切断裂产生更细的碎片。在实验室的拉伸和弯曲强度测试中观察到第一种机理，在实验室的脆性测试和动态冲击力下的现场爆破操作中观察到第二种机理。岩石和矿石的脆性可以通过脆性测试确定。已经设计出确定脆性值的测试设备，以适合水泥生产中使用的石灰石强度特性。确定了重晶石，大理石，石灰石和铝土矿的易碎性和储能应变能值，并将其与这些材料的相应邦定功指数（W_i）和可磨性指数（G）进行比较。还确定了被测材料的物理机械性能，以研究其对脆性和研磨性的影响。指数之间获得的关系出乎意料的良好一致性，具有很高的相关性（0.99和0.97）。因此，可以从脆性值估计出邦定工作指数和可磨性指数，该值可以比邦定测试更快地确定。但是对于某些岩石类型（例如安山岩），这种关系不成立。

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