Research on Precise Classification Technology of Tailings Sand

It is difficult to achieve dry and precise classification for fine sand characterized by small particle size, high content of micro-powder, and unstable gradation. In this study, a rectangle swing screen assisted by airflow & ultrasonic was employed to achieve precise classification of fine tailings. Through detailed process calculations and sample analysis, the following conclusions can be drawn: The movement trajectory of the fine sand within the rectangle swing screen follows a 360° parabolic path. The current theoretical formula for calculating the resistance coefficient of the transitional flow field within the airflow-assisted rectangle swing screen should be revised. After pre-dried, the magnetic tailings, vanadium-titanium magnetic tailings and molybdenum tailings were precise classified by the new multi-field coupled classifiers. The new classifiers enables the production of products with a mixed-grade rate of less than 5%. The classification efficiency is influenced by the inclination angle of the screen, the length of the sieve, the air velocity, the ultrasonic amplitude & etc., and parameters can be reasonably set according to engineering requirements. Furthermore, the prepared products have been successfully applied in the production of dry-mixed mortar and can be manufactured on a batch scale. The dry-mixed mortar containing tailings has been applied in urban renewal projects and has achieved good results.