Abstract

Objective In industrial sectors such as mineral resource development and metallurgy， material crushing serves as a critical process，and crushing efficiency directly affects the energy consumption of the entire production line.The double-roll crusher，as the core equipment for achieving medium and fine crushing of ores in mineral processing， primarily relies on the squeezing and shearing forces of its two rolls to perform crushing operations. In actual production， the particle size distribution of the crushed product not only directly affects mineral separation efficiency but also serves as a core indicator for evaluating crusher performance and capacity. Therefore， investigating the particle size distribution of crushed materials under different operating parameters of the double-roll crusher is of significant importance. To optimize the particle size distribution of crushed materials and enhance crusher productivity， this study determines the maximum theoretical feed particle size for double-roll crushers based on force characteristics and bite angle analysis. It further explores the influence of tooth roll structural parameters， operating conditions， and feed density on the final particle size distribution. The research methodology and conclusions facilitate the regulation of product particle size distribution and the optimization of crusher performance， thereby achieving efficient crushing operations with double-roll crushers.

Methods This study employed a coordinated research framework integrating discrete element method （DEM） simulations with systematic laboratory experiments. A rigorous mechanical analysis of the double-roll crushing principle was first conducted to define operating conditions， ensuring experimental reliability. The maximum theoretical feed particle size was derived based on the critical engagement angle. Subsequently， a numerical model was constructed using EDEM software， integrating the Tavares crushing model to accurately reproduce the dynamic evolution of the crushing process and quantitatively characterize the properties of the crushed product. This model simulated the dynamic crushing process of material particles and particle-equipment interactions. It was then employed to investigate the influence of various kinematic and structural parameters， roll gap， and rotational speed on the final particle size distribution. To complement the numerical simulation results， the third phase involved laboratory testing to independently examine the influence of feed density on the particle size distribution and crushing characteristics of the crushed product. Finally， through comprehensive quantitative analysis of both simulated and experimental datasets， the interaction mechanisms among roll gap， rotational speed， and material density were elucidated. This analysis revealed the collective influence of these factors on the product particle size distribution and equipment processing capacity， as well as the underlying patterns affecting the post-crushing particle size distribution.

Results and Discussion Based on the established simulation model and experiments， computational results indicated that crushed products were predominantly concentrated within the particle size range close to the roll gap dimension， demonstrating that the roll gap exerted a dominant constraining effect on the particle size distribution. When the roll gap size decreased from 3 mm to 1 mm， the negative cumulative yield rate for the 1~3 mm particle size increased by 22.5%， and the average product particle size decreased significantly from 2.89 mm to 1.56 mm. Regarding processing capacity， this study found that while increasing rotational speed initially enhanced throughput effectively， the rate of output growth gradually stabilized as speed continued to rise. This phenomenon indicated that although high rotational speeds initially increased material feed rates， mechanical limitations and particle slippage at extreme speeds hindered linear growth in processing capacity. Furthermore， increased feed density intensified interactions between particles during crushing. Enhanced material compaction promoted finer particle content while effectively reducing the proportions of coarse particles. A denser material bed elevated inter-particle stress， thereby enhancing the crushing ratio. However， excessively small initial feed particle size weakened inter-particle forces due to poor meshing， thereby reducing the crushing efficiency of the double-roll crusher.

Conclusion This study investigates the influence of different structural configurations and material parameters on the particle size distribution of products from double-roll crushers. Through a combined approach of numerical simulation and experimental research， analysis of structural and feed parameters indicates that the roll gap size is the key factor determining the proportion of particle size distribution. Reducing the roll gap alters the proportion of dominant particle sizes in the product， enhancing the fineness of the crushed materials， but this effect has a threshold. Increasing the rotational speed of the double-roll crusher initially raises output.However， beyond a certain speed， the rate of output increase diminishes， limiting the effectiveness of further speed increases. Increasing material density intensifies inter-particle compression and crushing， further refining crushed particles and enhancing the crushing ratio. Crushed products tend to concentrate heavily within the particle size range close to the roll gap dimension. Modifying material density has a limited impact on the proportion of the main particle size in the crushed product， and the roll gap dimension remains the primary determinant of this proportion， consistent with simulation results. Excessively fine particle size reduces the forces between particles， diminishing the crushing efficiency of the rolls on ore particles and hindering material fragmentation. Therefore， proper control of material particle size is essential for enhancing crushing efficiency.

Keywords： double-roll crusher； particle size distribution； discrete element method； crushing performance

Get Citation:LIU Quan， CAI Gaipin， WU Changping， et al. Particle size distribution characteristics of double-roll crusher products［J］. China Powder Science and Technology， 2026， 32（3）： 1-11.

Received:2025-11-24, Revised: 2025-12-31, Online: 2026-02-01.

Funding： The research was supported by the National Natural Science Foundation of China (Grant No. 52364025).

DOI：10.13732/j.issn.1008-5548.2026.03.015

CLC No:TB44          Type Code: A

Serial No:1008-5548（2026）03-0001-11