This paper introduces a methodology to determine the gravity-recoverable platinum group minerals (GRPGMs) of a stream, and behaviour of platinum group minerals (PGMs) in a ball mill-cyclone circuit. The GRPGM is determined by a modification of the method developed for gravity-recoverable gold (GRG). Mineral behaviour in the circuit employs element and GRPGM cyclone partition curves and cumulative element selection functions. The methodology is illustrated on the grinding circuit at Vale’s Clarabelle mill (Sudbury, Canada). As an example, GRPGM for platinum (Pt) in the ball mill-cyclone circulating load was about 80%. The cumulative selection functions of Pt and palladium (Pd) were ca. 1.3 times higher than the solids for size fractions above 212 μm, which moderated their buildup in the closed circuit, but were ca. 60% that of the solids below 212 μm which contributed to buildup of these sizes. The partition curves showed more than 90% of the Pt and Pd above ca 50 μm reported to the cyclone underflow. The buildup of PGMs in the circulating load and the high GRPGM offers an opportunity for gravity recovery.

本文介绍了一种确定流中可重力恢复的铂族矿物（GRPGM）以及球磨机-旋风分离器回路中铂族矿物（PGM）行为的方法。GRPGM是通过对重力可回收金（GRG）开发的方法进行修改而确定的。回路中的矿物特性采用元素和GRPGM旋风分离器分配曲线以及累积元素选择功能。该方法在Vale的Clarabelle工厂（加拿大萨德伯里）的研磨回路中进行了说明。例如，在球磨机-旋风分离器的循环负载中，铂（Pt）的GRPGM约为80％。Pt和钯（Pd）的累积选择函数约为。对于尺寸大于212μm的颗粒，其固体含量是固体的1.3倍，这虽然降低了其在闭合回路中的堆积量，但约为。低于212μm的固体的60％导致了这些尺寸的堆积。分配曲线显示，报告给旋流器底流的Pt和Pd超过50μm时，超过90％。循环载荷中PGM的堆积和高GRPGM为重力回收提供了机会。