ABSTRACT

More efficient liberation of valuable minerals from gangue would bring enormous benefits to the comminution process and the downstream beneficiation processes. However, whether particle-bed breakage can improve liberation compared with traditional grinding has been controversial. In this study, three types of iron ores with 3–0.425 mm were comminuted to −0.425 mm via the piston-die compression unit or the dry ball mill at essentially the same grinding degrees. Liberation analysis was performed using Mineral Liberation Analyzer (MLA) for each breakage method and the size fraction product. Statistical methods based on bootstrap resampling and standardized mean differences (SMD) were used to quantitatively analyze the significance of differences in the liberation distribution of iron oxide minerals with different breakage methods. MLA tests showed that the particle-bed breakage did not significantly improve the liberation degree compared to the ball mill grinding; the maximum difference of the proportion of 80–100% liberated iron oxide mineral in a certain size fraction with the two breakage methods was only 5%. The SMD was less than 1.2 in most size/composition classes, which indicated that the difference in the liberation distribution of iron oxide minerals between the two breakage methods was not statistically significant in most size/composition classes. The particle-bed breakage slightly improved the liberation of iron oxide minerals compared to ball mill grinding at the particle size of the products close to the grain size of the iron oxide minerals in the feeds.

摘要

更有效地从脉石中释放有价值的矿物将为粉碎过程和下游选矿过程带来巨大的好处。然而，与传统研磨相比，颗粒床破碎是否可以改善释放度一直存在争议。在这项研究中，三种类型的铁矿石（3-0.425毫米）通过活塞模压缩装置或干式球磨机以基本相同的研磨度被粉碎至-0.425毫米。使用矿物释放分析仪 (MLA) 对每种破碎方法和尺寸分数产品进行释放分析。采用基于自举重采样和标准化均值差（SMD）的统计方法，定量分析了不同破碎方法下氧化铁矿物的释放分布差异的显着性。MLA试验表明，与球磨机研磨相比，颗粒床破碎并没有显着提高游离度；两种破碎方法在一定粒度级数中释放出的氧化铁矿物比例为80%~100%的最大差异仅为5%。在大多数尺寸/成分类别中，SMD 小于 1.2，这表明两种破碎方法之间的氧化铁矿物释放分布差异在大多数尺寸/成分类别中不具有统计显着性。与球磨机研磨相比，颗粒床破碎稍微改善了氧化铁矿物质的释放，产品的粒度接近进料中氧化铁矿物质的粒度。