Study and application of the technology for high-efficiency desliming and dewatering of coarse slime

High ash of screen oversize and the presence of oversize particle in undersize material are a long-standing vexing trouble faced by coal preparation plant in coarse slime desliming and dewatering process. Based on analysis of the patterns of both liquid and solid phases passing through screen plate and the 3-mass vibration theory, an intelligent 3-mass desliming-dewatering fine screen is successfully developed. The screen has been introduced by several coal preparation plant for optimization of the screens originally used for such purpose. Field application of the screen shows that the higher the acceleration of screen surface, the higher the speed at which the liquid phase passes through the screen; the finer the particle size, the higher the hydrophilicity becomes and a higher vibration intensity is required for the finer size to pass through the screen because of the aggregation and deaggregation affect; for effective sizing of wet fine material, the screen needs to operate preferably with a high frequency and a small amplitude; the 3-mass fine screen developed can operate with a vibration frequency as high as 50 Hz, doubling that of ordinary screen; when the screen mesh is in vibration at such a high frequency, the screen frame remains motionless and only the vibrator and vibrating shaft undergo a slight vibration motion; the screen is high reliable in operation and its energy consumption is 50 percent or even less than conventional high-frequency screen; the screen is suitable for desliming and ash reduction of cleaned coarse slime, recovery of hard-to-float fine coal, sizing of ultrafine coal slime, dewatering of magnetic tailings of middling and refuse, and effective reduction of ash and moisture of slime product for improvement of economic performance of coal preparation plant.