Use of fracture mechanics parameters to characterize comminution

Abstract

This report is to investigate the use of fracture mechanics parameters (fracture toughness, specific work of fracture) to characterize comminution process. Comminution is a very important industrial process and is extremely low in efficiency. Establishment of a crushing index based on fracture mechanics principles is of great significance for improved machine design and enhanced efficiency. Single particle fracture study has been reviewed because it is considered the most elementary process in and provides the basis for comminution.

Rock fragmentation can be best described by fracture mechanics principles and concepts. The most fundamental concept in fracture mechanics is fracture toughness. Extensive review has been done on the fracture toughness application to rock fragmentation problems, and has found it has not been successfully used in comminution process. Further study is necessary to investigate the link between comminution and fracture toughens. Interrelation of fracture. toughness with other rock properties has been studied. Loading rate effects on fracture toughness has also been reviewed.

Fracture toughness testing for rock materials has also been studied. The SCB (Semi-Circular Bend specimen) method has been selected for its sound analytical background and ease of operation. A experimental proposal is made based upon the survey results. Single particle fracture is proposed to be conducted on the Allis-Chalmers High Energy Crush Test System, which, compared with other test apparatus, more closely simulates the actual crushers. Detailed procedures on how to use the test system has been given in the report.