Spatially permeable screening distribution characteristics of banana-type vibrating screen material groups and industrial application

Abstract

ABSTRACT Screening is a critical technology to achieve clean and effective use of coal. Due to their ability to achieve equal-thickness screening and excellent working efficiency characteristics, banana screens are widely utilized for material classification. The current work employs a vibration test and analysis system to investigate the laboratory-scale and industrial banana screens’ kinematic features. The screen surface’s amplitude gradients at the inlet and outlet ends of the laboratory and industrial scale banana screens were 0.5 mm and 7.5 mm, respectively, verifying the “strong-in, weak-out” transfer law of the vibration energy. The results of the 6 mm screening experiment in the laboratory indicated that the coal samples were concentrated in the middle of the screen surface with the highest screening efficiency of 95.05% and the lowest total mismatch content of 2.68%. A Birtley’s four-stage banana screen was utilized to classify the 6 mm raw coal during the on-site heavy media separation at the Tunbao coal processing plant. Besides, a better screening performance was obtained with an efficiency of 89.92% and total mismatch content of 5.31%. The differences in accuracy of the distribution rate curves were all less than 5%, indicating that the laboratory banana screen is a prominent guide for industrial applications.