Closed Circuit Cone Crusher
In designing a closed-circuit crushing stage, the question of how much circulating load should be carried is a very important one. It not only has a direct bearing upon the capacity of the stage; it determines the amount of screening surface, and the elevating capacity necessary to handle the load in the circuit. There is no "blanket" answer to this question. It must be analyzed for each case, on the basis of the operating characteristics of the particular size and style of crusher that is being considered for the job.
Open Circuit VS Closed Circuit
"Stage-crushing," as we use the term here, applies to open-circuit reduction in a flow line comprising two or more crushing stages, with scalping between each stage, but without close-circuiting any stage upon itself; except, perhaps, the final one. Generally speaking, such an arrangement works out more efficiently than one in which each stage is run in closed circuit. There is nothing to be gained by sending oversize rock back to the crusher that let it go through once, unless the stage is the final "clean-up" stage in the flow line. The oversize should go on to a stage wherein the setting is smaller, and where these oversize pieces will be crushed by positive metal-to-metal contact. The scalping between stages in such a system should remove most of the material which is smaller than the setting of the next following stage.