A method to evaluate the overall breakage degree of pre-weakening processing and its applications

The product fineness indicator t₁₀ and the pre-weakening degree indicator percentage change of A * b value (C_Ab) were used to described the two aspects of the breakage result of processing with pre-weakening effect. However, there lacks a method to evaluate the ‘overall’ breakage degree with a single index. It was observed that when the high voltage pulse breakage (HVP breakage or HVPB) induced cracks inside pre-weakened particles were consumed during impact breakage, the breakage characteristics of the progeny particles are the same to raw ore particles. Based on this phenomenon, the concepts of equivalent size S_ie and equivalent size reduction t_10e are proposed. Raw ore particles of size S_ie is ‘equivalent’ to pre-weakened particles of size S_i in terms of their impact breakage product size distribution. Therefore the value of S_i and the consequently derived t_10e can be used to evaluate the overall breakage degree of pre-weakened particles. The calculation procedure of S_ie and t_10e is demonstrated in the context of HVP breakage. It is found that the impact breakage product of pre-weakened particles can be well predicted from S_ie. In addition to the evaluation of overall breakage degree of pre-weakening processing, this method also has potential to apply in the simulation of comminution circuits with pre-weakening processing and the development of breakage model for processing with pre-weakening effect.