In order to improve the calculation efficiency of a discrete element EDEM (Discrete Element Method) numerical simulation software for micron particles, the particle model is linearly enlarged. At the same time, the parameters of the amplified particles were calibrated according to the Hertz-Mindlin with JKR (Johnson-Kendall-Roberts) contact model to make the amplified particles have the same particle flow characteristics as the actual particles. Actual tests were utilized to gather the angle of repose of the microfine iron tailings, which was then used as a reference value for response surface studies based on the JKR contact model from six factors connected to the fine iron tailings particles. The Plackett-Burman test was used to identify three parameters that had a significant effect on the rest angle: static friction factor; rolling friction factor; and JKR surface energy. The Box-Behnken experiment was used to establish a second-order regression model of the rest angle, and the significant parameters and the optimized parameters were: surface energy JKR coefficient 0.459; particle-particle static friction coefficient 0.393; and particle-particle dynamic friction coefficient 0.393, with a dynamic friction coefficient between particles of 0.106. By entering the parameters into the discrete element program, the angle of repose generated from the simulations was compared with the real test values, and the error was 1.56%. The contact parameters obtained can be used in the discrete element simulation of the amplified particles of fine-grained iron tailings, providing an EDEM model reference for the numerical simulation of fine-grained iron tailings particles. There is no discernible difference between the actual and simulated angles.

The most efficient method for recovering microfine-grained hematite ore is flocculation flotation. Because the flocculation–bubble mineralization process in flocculation flotation has yet to be well investigated, a series of experimental investigations on hematite flocculation–bubble were conducted to better understand the hematite flocculation–bubble interaction process. The results show that as the flocculant size increases, the sliding time of the flocculant to the bottom of the bubble shortens, and the change in the instantaneous dynamic velocity is slower when the diameter of the fixed bead is 544.52 μm, which is more favorable to flocculant adhesion on the bubble surface. When the bubble diameter is 544.52 μm and the floc diameter is 39.65 μm, the shortest time is 49.5 ms, and the maximum value of instantaneous velocity is 28.67 μm·ms⁻¹. According to the force analysis of the floc on the bubble surface, when the particle size of the floc is 39.65 μm and the bubble diameter is 544.52 μm, the desorption force is 4.99 × 10⁻³ mN·m⁻¹ larger, and the adhesion force is 7.08 × 10⁻⁴ mN·m⁻¹ smaller. The smaller Bond constant Bo′ is 0.14. In that moment, the flocs in the sodium solution are very stable.