In this study, to obtain the contact parameters of particulate materials accurately and quickly in residual film mixture after sieving, the contact parameters of particulate materials were calibrated via a physical test and simulation test. By using the self-made dynamic angle of a repose measurement test bench, the dynamic angle of repose of the particulate materials was measured at 41.32°, and the standard deviation was 1.33°. A discrete element simulation of the dynamic angle of the repose test was performed via an EDEM screening experiment design through a simulation of a combination of different parameters, with the dynamic angle of repose as the response value. Through simulation experiments, three significant influencing factors, as well as the level range of each factor, were confirmed. By using the response surface experiment, a mathematical model of the dynamic angle of repose and the three most influential parameters was created. The analysis of variance showed that the determination coefficient R² and the correction determination coefficient R²_adj were 0.9824 and 0.9598, respectively. The model had a good fit. The variable coefficient was 2.06% and the lack of fit was non-significant, which showed that the regression model was very significant, and the dynamic angle of repose could be predicted according to the model. By solving the optimization for the mathematical model, the optimal combination of parameters with three important influencing factors were obtained. The results showed that the coefficient of the static friction between soil and soil was 0.38, the coefficient of the rolling friction between soil and soil was 0.08, and the coefficient of the static friction between cotton residue and cotton residue was 0.33. The relative error of the dynamic angle of repose between the simulation with the optimal parameter combination and the physical test value was 2.64%. The results could provide a reference for the calibration of the discrete element model parameters of other agricultural particulate material, as well as provide a theoretical basis for the design of related collecting and conveying machinery.

This study investigates the incomplete separation caused by the adhesion and bonding between residual film and soil, examines its adverse impacts on farmland soil remediation and environmental pollution, and proposes a multistage sieving roller device to achieve residual Film–Soil separation in the plough layer. The overall structure and working principle of the device were described, and the sieving process during operation was analyzed. The fragmentation characteristics of the film–soil composite under impact loading were investigated using an analytical approach. Based on the characteristic parameters of soil and residual film in the plough layer, the key structural parameters of the sieving rollers were determined. A test platform of the multistage sieving roller film–soil separation device was constructed, and physical experiments were conducted using the Box–Behnken response surface methodology. The rotational speed, gap, and inclination angle of the sieving rollers were selected as experimental factors, with the soil removal rate and film leakage rate as evaluation indices. Analysis of variance revealed high coefficients of determination (R²) for the soil removal rate (0.9909) and the film leakage rate (0.9927), demonstrating an excellent fit of the model. The optimal combination of parameters was determined as follows: a sieving roller rotational speed of 450 r·min⁻¹, a gap between the sieving rollers of 21.48 mm, and an inclination angle of 10° for the sieving rollers. Under these conditions, the soil removal rate reached 92.08%, and the film leakage rate was 5.74%, meeting the requirements for separating soil and residual film. This study presents a novel method and provides a technical reference for the efficient separation of residual film and soil in the plough layer, thereby contributing to an improved recovery rate of residual film. The growing urgency to mitigate farmland soil pollution has necessitated the advancement and widespread adoption of mechanized technologies and equipment for residual film recovery.