Research on surface segregation and overall segregation of particles in a rotating drum based on stacked image

• Published in: Powder technology 2021-04, Vol.382, p.162-172
• Main Authors: Huang, Peng, Miao, Qiuhua, Ding, Yifei, Sang, Gao, Jia, Minping
• Format: Article
• Language: English
• Subjects: Ball mill; Diameters; Discrete element method; Image analysis; Image processing; Mixing and segregation; Object recognition; Particle segregation; Qualitative analysis; Rotation; Segregation index; Stacked image
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2020.12.063

At present, image recognition methods have been widely used in the research on measuring particle mixing and segregation in rotating drums. However, currently commonly used methods tend to study mixing and segregation from the perspective of the radial surface of the particles, but rarely from the perspective of the axial surface. Whether the data obtained from the particle surface (radial segregation or axial segregation) can reflect the degree of mixing and segregation of the entire particle system (overall segregation) is still a question worth studying. In this work, an image analysis method based on stacked images to measure the degree of surface segregation is proposed. The drum length to diameter ratio (L/D) and particle filling rate are used as operating parameters. And the discrete element method (DEM) verified by experiments has studied the difference between the surface segregation and the overall segregation of the binary particle groups (different particle sizes) in the rotating drum. This paper compares the qualitative characteristics (particle segregation characteristic patterns) and quantitative characteristics (particle segregation degree) of surface and overall mixing and segregation in detail. The results show that for short drums, radial segregation index can be used to quantify the overall degree of segregation. While for long drums, axial segregation index can be used to quantify the overall degree of segregation. [Display omitted] •An image-stacked method to measure particle segregation degree is proposed.•The overall and the axial segregation index reach the maximum meanwhile.•Radial segregation index can quantify overall segregation process for short drums.•Axial segregation index can quantify overall segregation process for long drums.