Novel size segregation indices for multi-sized particle stockpiles

Abstract

Size segregation is an unavoidable problem in materials handling and storage. The size segregation in a stockpile will send different particle sizes to different locations in the stockpile. This phenomenon will result in the comminution process receiving varying feed sizes depending on the feeders' layout. The fluctuations in feed size will then impact the performance of comminution and downstream processes. Therefore, qualifying size segregation is an important topic for any research related to size segregation.Whilst size segregation is a recognised factor in operations, there is no mature index to quantify the degree of size segregation for multi-sized materials. In this research, after reviewing the existing size segregation indices and identifying their strengths and limitations, two novel-sized segregation indices are proposed for quantifying size segregation in stockpiles and bins. The proposed indices are based on the variation in the particle size distribution of different locations of a stockpile. The first index is an improvement to an existing index (Li et al., 2017). The authors propose the second index and it is based on the differences in the particle size distribution curves at each section of the stockpile or bin. A number of small-scale experiments have been conducted in the laboratory to investigate the suitability of the proposed indices and their advantages over the existing indices. These experimental results validate that the proposed indices are suitable for quantifying size segregation, and they perform better than the existing indices. As a result, the new size segregation indices can be utilised to quantify the segregation in stockpiles, which can then be used to model and predictor inform the downstream process for reacting and optimising the process.