CRUSHERS

Several types of crushers are modeled in MODSIM. In this module we will consider three types: primary crushers (gyratory and jaw crushers), secondary crushers (standard cone crushers) and tertiary crushers (short head cone crushers).

Primary Crushers

The models used for primary crushers are elementary and follow a method that has been traditionally used by crusher manufacturers. The product size distribution is assumed to follow a standard pattern which is normalized with respect to a single reference size on the curve which is often d80. The reference size is closely related to the open size setting of the crusher. The standard size distributions have been determined from many crushers operating in industry. In spite of the simplicity of this model, the results are adequate for many simulations since the product from these primary crushers is generally the feed to a further stage of crushing using standard or short head cone crushers. An improved form of the model developed by Csoke et al. is also available for primary crushers. The simulation of primary crushers is illustrated in exercise 3-3.

Standard and Short Head Cone Crushers

The models for both standard and short head cone crushers are based on the idea of internal breakage and classification developed by Whiten. This model allows calculations of realistic size distributions in the product given the size distribution in the feed and the closed side setting of the crusher. These models are described in Section 5.6 of the textbook and in Technical Notes 5: Models for Crushers.

The model for the standard cone crusher is demonstrated in exercise 3-4 and for the short head crusher in exercise 3-5.