When it comes to the screening method of alluvial placer tin ore, shaftless trommel screen and cylindrical ore washing and screening machine are two common and effective equipment. Their screening principles and advantages are as follows:
Sieving principle:The shaftless trommel uses the self-weight and friction of the screen cylinder to screen the ore in layers through rotational motion, the large particles roll down along the screen, and the small particles fall into the collection chute below through the screen hole.
Advantages:
High efficiency: The rotary motion makes the screening speed fast and efficient, which is suitable for the screening of a large number of ores. Simple: simple operation, easy maintenance, easy to adjust and control screening parameters, suitable for on-site production environment. 
Sieving principle:The cylindrical ore washing and screening machine mixes the ore with water and puts it into the screening equipment, and separates the ore and water through the rotation and friction inside the equipment, so as to realize the integrated operation of ore washing and screening.
Advantages:
Multi-functional: The integrated washing and screening functions can complete the cleaning and coarse screening of ore at the same time, saving time and labor costs. Cleaning: The ore is cleaned by water washing, which effectively removes soil and impurities and improves the effect of the subsequent beneficiation process. Energy saving and environmental protection: water resources can be used in the washing process to reduce environmental pollution and meet the requirements of energy conservation and environmental protection. 
The application of these screening equipment is of great significance in the beneficiation process of alluvial placer tin ore, which can effectively improve the screening efficiency and reduce the energy consumption in the screening process, so as to achieve efficient utilization of resources.