During the high-pressure comminution process, rather than being crushed between the roller surfaces, individual grains or particles are, in effect, compacted to a dense flake through exposure to relatively high pressures. Following de-agglomeration, the flake normally shows a substantial amount of completed or cracking arising from the particle surfaces. This highly efficient comminution process requires considerably less energy compared to conventional crushers and mills, due to relatively uniform loading of the material in the compression zone and very short retention time. The system has minimal energy requirement for material transport in the HPGR.
The movement of the floating roller is based on the principle of high-pressure comminution with a roller press. In HPGRs, the roller gap adjusts itself automatically when subjected to a given pressure between the rollers. The extent of the roller movement at the gap is a function of the stiffness of the hydraulic system in relation to the reaction forces exerted by the processed material, and therefore varies accordingly. This design feature guarantees that during the comminution process, all the feed material passes through the roller gap under the same process conditions, thus ensuring that the HPGR output quality remains constant.
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