Yu Tiantian1，2，Xiao Gang1，2，3， Chen Zejia3，4，Hu Yun1，Zhou Lei1，2
1.School of Advanced Manufacturing， Nanchang University， Nanchang 330031， China； 2.Huizhou Jinyuan Intelligent Robot Co.， Ltd.， Huizhou 516006， China； 3.Jiangxi Copper Technology Research Institute Co.，Ltd.，Nanchang 330096，China；4.College of Mechanical and Vehicle Engineering， Hunan University， Changsha 410082， China
Abstract
Objective Photoelectric sorting is a core technological means in the mineral processing field to improve ore grade and recovery rate， which requires materials to pass through the sorting area in a uniform and stable single layer. However， traditional spreading systems rely on the inertia and gravity of material throwing， lacking active control of the flow trajectory， leading to lateral particle size and density segregation， significantly reducing sorting accuracy. The objective of this paper is to solve the problems of uneven spreading and easy overlapping and stacking of materials on the belt during ore photoelectric sorting， to design a reciprocating spreading device， and to determine its optimal structural parameters for enhancing sorting efficiency and accuracy.
Methods The mixing mechanism of the “feeding-rectifying-uniform spreading” three-stage coupling process of the reciprocating spreading device was analyzed， and the mechanical model of particles driven by the crank-link mechanism was studied. A three-dimensional model of the reciprocating spreading device was established in EDEM using the discrete element method （DEM）. Material parameters and contact models of ore particles （density 2 500 kg/m³） and the device were set. Under a rotational speed of 40 r/min and a generation rate of 6~18 kg/s， the spreading process was simulated at different spreading plate movement frequencies （0.4， 0.5， 0.6 Hz），spreading plate spacings （100， 200， 300 mm）， and conveyor belt inclination angles （10°， 25°， 40°）. The particle mass in each grid cell at each time step was exported from EDEM， and the standard deviation of cumulative particle mass was calculated using MATLAB as the uniformity evaluation indicator. Finally， a three-factor， three-level orthogonal experiment was conducted to determine the optimal structural parameters， and the optimization effect was verified by comparing with a control group without spreading plates.
Results and Discussion The results indicated that the uniformity change during the reciprocating spreading exhibited distinct characteristics at different stages.The standard deviation fluctuated greatly in the initial stage（indicating system instability），gradually stabilized in the intermediate stage， and finally remained at a low level. Spreading plate spacing， conveyor belt inclina-tion angle， and spreading plate movement frequency each exerted different effects on spreading uniformity. A spacing of 200 mm achieved a better spreading performance （standard deviation 0.382 1） than other spacings， a spacing of 100 mm easily caused particle jamming and blockage， while a spacing of 300 mm led to excessive dispersion of falling trajectories and edge accumulation. An inclination angle of 40° effectively suppressed edge accumulation， outperforming other angles. An angle of 10°resulted in static friction dominance， causing particle retention， while a larger angle exacerbated conveyor belt wear. The optimal spreading effect was achieved at a frequency of 0.4 Hz， which， when combined with a spacing of 200 mm and an inclination of 40°， achieved a dynamic balance between the sweeping rhythm of the spreading plate and material flow. Excessively high frequency caused particle splashing and diffusion， while too low frequency resulted in uneven material distribution.
Conclusion A three-level， three-factor orthogonal experiment is conducted with spreading plate spacing， movement frequency， and conveyor belt inclination angle as factors， and the standard deviation of particle mass at the discharge outlet is used as the evaluation indicator. Range analysis of the nine experimental groups shows that the influence of the factors on spreading uniformity， in descending order， is： spreading plate spacing > conveyor belt inclination angle >spreading plate movement frequency. The optimal spreading performance of the reciprocating spreading device is achieved at a spreading plate spacing of 200 mm， a movement frequency of 0.4 Hz， and a conveyor belt inclination angle of 40°， with a standard deviation of 0.342 2. Compared with the control group （standard deviation 0.423 3） without the distribution bin and spreading plates， the relative improvement in spreading uniformity is 19.16%， demonstrating a significant improvement.
Keywords： discrete element method； uniform spreading； parameter optimization； orthogonal experiment
Get Citation:Yu Tiantian， Xiao Gang， Chen Zejia， et al. Optimization design of reciprocating spreading process based on EDEM simulation［J］. China Powder Science and Technology， 2026， 32（6）： 1-13.
Received：2026-03-06， Revised： 2026-05-18，Online： 2026-06-30。
Funding： The research was supported by the National Key R&D Program of China (Grant No. 2023YFC3904200),the National Natural Science Foundation of China (Grant No. 52471055), and the Key R&D Program of Jiangxi Province (Grant No. 20243BBG71033).
CLC No.：TB4； TD45
Type Code：A
Serial No.：1008-5548（2026）06-0001-13
