Experimental evaluation of the conjugate anvil hammer mill – Comparison of semi-confined to confined particle breakage

Abstract The Conjugate Anvil Hammer Mill (CAHM) was identified as a novel energy efficient technology by the Canadian Mining Innovation Council that has the potential to replace conventional crushers and Semi-Autogenous Grinding (SAG) mills. Discrete Element Method (DEM) modelling showed that the CAHM requires significantly less energy in comparison to existing comminution technologies including High Pressure Grinding Rolls (HPGR). However, experimental evidence was required to validate this potential and to address operational questions. In order to evaluate the CAHM, piston-die testing was conducted to represent the comminution conditions in the CAHM for comparison to the HPGR. Three piston-die conditions were tested including low pressure semi-confined compression as generated in the CAHM, low pressure confined compression, and high pressure confined compressions as generated in the HPGR. The particle breakage was investigated and compared in terms of applied force, energy consumption, product particle size reduction and particles’ surface area generation. Results showed that the CAHM test apparatus required a much lower force and produced a finer product particle size distribution and higher surface area when compared to low pressure confined compression. When compared to high pressure confined compression (HPGR), up to 37% and 22% energy savings were achieved by the CAHM for a soft gold ore and a harder copper ore, respectively. The results demonstrated that the CAHM technology has potential to improve energy efficiency in the comminution process.