Abstract Numerous studies have reported the so-called fish-hook effect on granulometric efficiency curves of hydrocyclones. This effect has been reported since laser diffraction particle size analysers started to be used. In this work a 15-mm-diameter Bradley hydrocyclone has been used to separate a suspension of calcium carbonate 1,2% in volume to analyse the fish-hook effect. The Malvern Mastersizer 2000 particle size analyser has been used and both Fraunhofer's and Mie's light scattering theories have been assessed. It has been concluded that the fish-hook effect is a result of using Fraunhofer's correlation to determine the size of particles which are knowingly out of its range of validity (diameters smaller than 50 μm) or using Mie's correlation with inappropriate particles' imaginary refraction indexes (IRI). A method to determine the appropriate IRI in the Malvern Mastersizer 2000 is also presented. The fish-hook effect is therefore a misuse of laser diffraction particle size analysers.

中文翻译：

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水力旋流器粒度效率曲线中的鱼钩效应：激光衍射粒度分析仪的误用

摘要 大量研究报道了所谓的鱼钩效应对水力旋流器粒度效率曲线的影响。自从开始使用激光衍射粒度分析仪以来，就已经报道了这种效应。在这项工作中，一个 15 毫米直径的布拉德利水力旋流器被用来分离体积为 1.2% 的碳酸钙悬浮液，以分析鱼钩效应。已使用 Malvern Mastersizer 2000 粒度分析仪，并评估了 Fraunhofer 和 Mie 的光散射理论。已经得出的结论是，鱼钩效应是使用弗劳恩霍夫相关性来确定明知超出其有效性范围（直径小于 50 微米）的粒子的大小或使用米氏相关性与不适当粒子的虚折射指数的结果(IR)。还介绍了一种在 Malvern Mastersizer 2000 中确定适当 IRI 的方法。因此，鱼钩效应是对激光衍射粒度分析仪的误用。