The two stages of rock breaking and grindings are the most composing part of all the other operations in the ore beneficiation plants so that they are highly valued and emphasized. The equipment investment amount of this production line is extremely high, the electricity consumption is also huge, and the maintenance and repair cost is also very high, and what is more, the granularity of the final products of the rock crushing operation directly influences the efficiency of the rock grinding and the cost of the ore beneficiation operation. For this reason, how to improve the efficiency and the output of the rock breaking and grinding operation has always been the important link for the ore dressing plants in order to reduce the energy consumption and the operational cost and improve economic benefits. rotary kiln,ball mill,Mineral Processing  At present, the majority of the ore dressing plants in our country adopts three-stage rock crushing technology, however, the four-stage and two-stage rock crushing technology are also used in some plants. Among them, the fine crushing work often adopts the closed circuit rock crushing, as for which, the product granularity of the fine crushing work is controlled by the closed circuit examination screening device, and generally speaking, the rock particles bigger than 20mm will be sent back the fine crushing equipment until the granularity of the products is qualified. In addition, many circulate belt conveyors are needed in this production line which directly increases the investment in the equipment and the workshop and the equipment maintenance cost. Especially when the rain reason comes, the rocks will become so moist that they will bond together, and the examination screening efficiency will be lowered which will increase the workload of the belt conveyors and further decrease the rock breaking efficiency. As for the open circulate rock breaking technology, since there are still many big-sized rocks in the final products crushed by the fine crushers, they will seriously reduce the rock grinding efficiency of the grinding machine after they go into the rock grinding equipment. Generally speaking, the granularity of the materials they are fed into the grinding machine in the ore dressing plants is about 20mm.