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Advances in high-pressure grinding roll (HGPR) technology since its first commercial application in the cement industry include new roll wear protection techniques and new confinement systems. The latter contribute to reductions in the edge effects in an attempt to reach a more homogenous product size along the rolls. Additional advances in this technology have been made in recent years, while modeling and simulation tools are also reaching maturity and can now be used to subject such novel developments to detailed scrutiny. This work applies a hybrid approach combining advanced simulations using the discrete element method, the particle replacement model and multibody dynamics to a phenomenological population balance model to critically assess two recent advances in HPGR technology: spring-loaded cheek plates and the offset roller press. Force and torque controllers, included in the EDEM 2022.1 software, were used to describe the responses of the geometries in contact with the granular material processed. Simulations showed that while the former successfully reduced the lateral bypass of the material by as much as 65% when cheek plates became severely worn, the latter demonstrated lower throughput and higher potential wear but an ability to generate a finer product than the traditional design. [ABSTRACT FROM AUTHOR]

Cost‐effective polymeric composites were successfully prepared by melt blending granitic quarry waste (GQW) with high‐density polyethylene (HDPE). The GQW is a waste generated during the production of manufacture fine aggregates (MFA) from crushed gneiss rock and contains significant amount of mica with iron in its structure. Different sieving and milling procedures were employed. The materials were characterized by mechanical and dynamic‐mechanical properties and scanning electron microscopy. Moreover, the influence of the GQW on the microwave absorbing properties in the X‐band frequency range was investigated. The presence of mica and iron compound in the GQW provides a dual function to the filler: toughening agent with microwave absorbing capacity. Indeed, the addition of 5 wt% of GQW previously sieved and milled by dry or wet‐grinding approach resulted in composites with outstanding toughness, modulus and elongation at break. Simulated RL studies revealed electro‐magnetic attenuation of −25 dB at 8.7 GHz. Such successful use of a waste generated in the production of a concentrate (MFA) not only contributes to the economics of the quarrying operation, but also to its environmental sustainability, since it replaces disposal of this product, which could lead to dust emissions, given its fine size and low moisture content. [ABSTRACT FROM AUTHOR]