The ore crushing and screening process involves crushing and screening ore. There are various types of crushing and screening processes, which can be distinguished based on the following three factors: the number of crushing stages, the configuration relationship between the crusher and screening machinery, and whether the oversize material is returned to the crusher for further crushing. Commonly used screening equipment in concentrators includes circular vibrating screens and linear vibrating screens.

Classification by Number of Crushing Stages: Based on the number of crushing stages, processes can be classified as single-stage, two-stage, three-stage, and four-stage crushing. Single-stage and four-stage crushing are rarely used except in very special cases. Two-stage and three-stage crushing are more common, especially the three-stage crushing process.

Classification by Configuration Relationship between Screening Machinery and Crusher: Based on the configuration relationship, processes can be classified into pre-screening, inspection screening, and pre-inspection screening. The types of screening are shown in the figure.

Based on whether the oversize product is returned to the crusher for further crushing, ore can be classified into two types: open-circuit crushing and screening processes and closed-circuit crushing and screening processes. Open-circuit crushing and screening is a process where the material is not returned, while closed-circuit crushing and screening involves returning the crushed product to the screening machinery for further screening. Closed-circuit crushing processes are used only for one stage of the crushing operation, providing ore with strict particle size control and uniform particle size distribution for grinding operations.

When the mine is small in scale, the raw ore particle size is small, and the equipment used is also small, a two-stage closed-circuit crushing and screening process can be used when the particle size of the crushed product from two stages meets the requirements of grinding operations. Two-stage open-circuit crushing and screening processes are mostly used in gravity separation plants. The second stage of crushing is used as raw material for a rod mill for coarse grinding before being supplied to the mineral processing operation; in effect, a rod mill replaces the third stage of crushing.

While three-stage open-circuit crushing and screening processes can meet the particle size requirements of crushing operations, the uniformity of the product particle size is difficult to guarantee, and therefore they are not widely used in mineral processing plants. The three-stage closed-circuit crushing and screening process not only meets the particle size requirements of grinding operations, but also ensures good particle size uniformity due to strict control of the product by the screen, which is beneficial for increasing the throughput and grinding efficiency of the ball mill. The three-stage closed-circuit crushing and screening process is currently the most widely used crushing and screening process.