Two stage comminution

Abstract

A two-step method for separating mineral grains from their ores is practised by first applying a shock discharge directly through the ore sample producing shock waves emanating from along the discharge path and reflected shock waves (tension waves) from grain boundaries and other discontinuities in the ore, such tension waves resulting in tensile stresses in the ore greater than the strength of the boundary or discontinuity whereby to gross spall the sample generally along the discharge path and to microfracture the region near the discharge path. The second step comprises comminuting the microfractured ore by impact or non-impact means to further reduce the ore generally along microfractures wherein considerably less energy is expended in the second step than would be required to reduce the ore to the same condition without the first step. A second non-impact step is preferably the application of acoustic energy to the microfractured region of the ore resulting in enlargement of microfractures and subsequent spalling of these microfractured regions.

Dependencies are inferred from the claim text.